JPWO2006014028A1 - Sweet potato stem and leaf extract and use thereof - Google Patents

Abstract

An object of the present invention is to obtain a polyphenol-containing extract having various physiological functions such as antioxidant activity, tyrosinase inhibitory activity, hepatoprotective activity, absorption inhibition of sugar and neutral fat, etc. from an inexpensive raw material by a simple method. And Specifically, the above-mentioned problems are solved by a polyphenol-containing water-soluble sweet potato foliage extract obtained from sweet potato foliage, a method for producing the same, a functional food containing the sweet potato foliage extract, a functional material, an antioxidant, and a hepatoprotectant. , A tyrosinase inhibitor, a sugar absorption inhibitor, a neutral fat absorption inhibitor, and the like.

Description

  The present invention relates to a water-soluble sweet potato stem-and-leaf extract containing polyphenol and a method for producing the same. The present invention also provides a functional food / beverage product, functional material, pharmaceutical product, antioxidant, hepatoprotectant, tyrosinase inhibitor, sugar absorption inhibitor, neutral fat absorption inhibitor comprising the sweet potato foliage extract as an active ingredient. It also relates to agents for preventing and treating obesity, antidepressants, anti-fatigue agents, deodorants, fats and oils and fat-containing foods. Furthermore, this invention relates to the food / beverage products containing the said sweet potato foliage extract.

Polyphenol compounds are widely contained in plants as plant secondary metabolites, and it is known that their types are diverse. These polyphenol compounds have been studied in the field of pharmacy for a long time because of their various physiological activities, and in recent years, they have attracted attention in the field of food chemistry.
Among them, tea polyphenols (catechins), which have recently been concentrated on research, include antibacterial, antiviral, antioxidant, antimutation, anticancer, platelet aggregation suppression, blood pressure increase suppression, blood cholesterol reduction, It has been recognized that it has a very wide range of physiological effects such as anti-caries, anti-allergy, intestinal flora improvement, deodorization (Japanese Patent Laid-Open Nos. 63-214183, 2-6499, and 4-178320). JP 2002-326932 A).
On the other hand, for sweet potatoes, a Brazilian varieties called "Simon-mochi", products of tuberous root powder and their stems and leaves made into tea are sold as health foods. There is a report that investigated the polyphenol content and antioxidant activity of freeze-dried hot water extract of Simon bud leaves and identified chlorogenic acid and caffeic acid as components of polyphenol by HPLC analysis (Journal of Japan Society for Food Science and Technology (2002), 49 (10), 683-687).
Moreover, about the component contained in the sweet potato leaf native to Brazil, from a sweet potato leaf alcohol extract, quercetin-3-glucoside (quercetin-3-glucoside), kaempferol-4 ', 7-dimethyl ether (kaempferol-4', 7-dimethyl) ether), ombuin, quercetin, quercetin-3 ′, 4 ′, 7-trimethyl ether (quercetin-3 ′, 4 ′, 7-trimethyl ether), β-sitosterol and sucrose There are reports that seven components of (sucrose) have been isolated (Zhongcaoiao (1994), 25 (4), 179-81). As flavonoids of Chinese sweet potato leaves, quercetin-3-o-β-D-glucopyranosyl- (6 → 1) -o-α-L-rhamnopyranoside (quercetin-3-o-β-D-glucopyranosyl- (6 → 1) -o-α-L-rhamnopyranoside), kaempferol-4,7-dimethyl ether, quercetin-3-o-β-D-glucoside (quercetin-3-o-β) -There is also a report that D-glucoside and quercetin were isolated by HPLC (Journal of Instrumental Analysis (1996), 15 (1), 71-74), while the leaf lyophilized powder of 60 kinds of sweet potatoes methanol When the polyphenol component was identified by HPLC analysis of the extract, it was reported that the main component was caffeic acid and five derivatives thereof, and the same component was detected in all varieties (Journal of Agricultural and Food Chemistry (2002). ), 50, 3718-3722).
Regarding the functionality, there is a report that the ground potato crushed material has the effect of suppressing blood glucose level increase and blood pressure increase (Kyushu Okinawa Agricultural Research Center, [Online], [Search August 4, 2004], Internet, <URL:
http: // konarc. naro. affrc. go. jp / press / 200404024 / index. html>. Moreover, it has been reported that the ethanol extract of above-ground sweet potato has α-amylase inhibitory activity, α-glucosidase inhibitory activity, and ACE inhibitory activity (Japanese Patent Laid-Open No. 2004-75638).

Currently, most of the cultivated sweet potatoes are used for food and processing of tuberous roots. On the other hand, the stems and leaves are only partially edible, but most are unused. Attempts have been made to identify the polyphenol component of sweet potato leaves, but the reported components vary from literature to literature, and there is no consensus. In addition, no attempt has been made to obtain a water-soluble extract suitable as a functional food material from sweet potato stems and leaves.
Polyphenols contained in plants are known to have a wide range of physiological effects, and are extracted from plants such as tea and applied to functional foods. In order to adapt to functional foods, the concentration to exert the functionality is important. In addition to the increase in cost when the effective concentration in the case of exhibiting functionality is increased, the taste of polyphenol may become a problem and may be difficult to use in foods. Polyphenols are known to have many strong bitter tastes like tea catechins, and those that exhibit functionality even at low concentrations are required. In addition, extracts containing polyphenols such as ginkgo biloba extract and soybean isoflavone may be sparingly soluble in water, but those having good water solubility are required for addition to beverages and the like.
In order to produce a polyphenol-containing extract more efficiently and economically, the present inventors screened various raw materials, examined a method for producing a polyphenol-containing extract, and further obtained the polyphenol thus obtained. The physiological action of the contained extract was examined. As a result, we extract sweet potato stems and leaves as raw materials, extract them using a water-containing organic solvent to obtain water-soluble components, and purify the polyphenol fraction to efficiently extract polyphenols at high concentrations and excellent water solubility. I found that I can get well. Moreover, when the physiological effect of the said extract was investigated, it discovered that it had the high activity which exceeded a prediction significantly, and reached | attained this invention.
That is, the present invention provides a water-soluble sweet potato foliage extract containing polyphenol, a method for producing the same, uses of the sweet potato foliage extract, and the like as described below.
(1) A water-soluble extract derived from sweet potato foliage, wherein the polyphenol content is 10% or more.
(2) The sweet potato stem and leaf extract according to (1) above, wherein the polyphenol content is 20% or more.
(3) The sweet potato shoot extract according to (1) or (2) above, which contains at least quercetin-3-glucoside as a component of polyphenol.
(4) The sweet potato foliage extract according to any one of (1) to (3) above, wherein the content of quercetin-3-glucoside in the polyphenol is 1% or more of the sweet potato foliage extract.
(5) The sweet potato shoot extract according to any one of (1) to (4) above, which contains at least quercetin-3-glucoside and 3,5-dicaffeoylquinic acid as components of polyphenol .
(6) A water-soluble extract derived from sweet potato foliage, which contains at least quercetin-3-glucoside and 3,5-dicaffeoylquinic acid as polyphenol components.
(7) A sweet potato foliage extract derived from a sweet potato foliage, which contains at least quercetin-3-glucoside, chlorogenic acid and 3,5-dicaffeoylquinic acid as polyphenol components.
(8) A water-soluble solution containing polyphenol, comprising a step of extracting sweet potato stems and leaves with a water-containing organic solvent, and a step of removing the organic solvent from the extract obtained by the extraction step to obtain a water fraction. Method for producing sweet potato stem and leaf extract.
(9) The production method according to (8), further comprising a step of purifying polyphenol after the step.
(10) The production method according to (8) or (9) above, which comprises, as a previous step, any one of drying, pulverization, heating, roasting of sweet potato foliage, or a combination thereof.
(11) The production method according to any one of (8) to (10) above, wherein the hydrous organic solvent is ethanol and the content is 40 to 90%.
(12) The production method according to any one of (8) to (11) above, wherein the ethanol content is 60%.
(13) A water-soluble sweet potato shoot extract containing polyphenols obtainable by the production method according to any one of (8) to (12) above.
(14) It can be obtained by the production method according to any one of (8) to (12), has a polyphenol content of 10% or more, and contains at least quercetin-3-glucoside as a component of the polyphenol. Water-soluble sweet potato stem and leaf extract characterized by
(15) A water-soluble sweet potato stem and leaf extract obtainable through a step of water-extracting sweet potato stems and leaves, having a polyphenol content of 10% or more and containing at least quercetin-3-glucoside as a component of the polyphenol A water-soluble sweet potato shoot extract characterized by the above.
(16) The above (1), (2), (3), (4), (5), (6), (7), (), wherein the sweet potato variety belongs to white sweet potato 13) The water-soluble sweet potato shoot extract according to (14) or (15).
(17) The above-mentioned (1), (2), (3), (4), (5), (6), (7), (13), ( 14) The water-soluble sweet potato shoot extract according to (15) or (16).
(18) The above (1), (2), comprising a step of any one of drying, pulverization, heating, roasting of sweet potato foliage, or a combination thereof in the previous stage of the production process of the sweet potato foliage extract , (3), (4), (5), (6), (7), (13), (14), (15), (16) or (17) water-soluble sweet potato foliage extract .
(19) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or a functional food or drink comprising the sweet potato stem and leaf extract according to (18) as an active ingredient.
(20) It has one or more functions of antioxidant, liver protection, tyrosinase inhibition, sugar absorption inhibition, neutral fat absorption inhibition, obesity prevention / improvement, antidepressant and anti-fatigue. Functional food and drink.
(21) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or a functional material comprising the sweet potato stem and leaf extract according to (18) as an active ingredient.
(22) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or a pharmaceutical product comprising the sweet potato foliage extract according to (18) as an active ingredient.
(23) Described in (22) having one or more of the following effects: antioxidant, liver protection, tyrosinase inhibition, sugar absorption inhibition, neutral fat absorption inhibition, obesity prevention / improvement, antidepressant, anti-fatigue Pharmaceutical products.
(24) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or an antioxidant comprising the sweet potato shoot extract according to (18) as an active ingredient.
(25) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or a deodorant comprising the sweet potato stem and leaf extract according to (18) as an active ingredient.
(26) Water-soluble sweet potato stem and leaf extract containing polyphenol, or (1), (2), (3), (4), (5), (6), (7), (13), ( 14), (15), (16), (17) or an oil and fat-containing food deterioration preventive agent comprising the sweet potato shoot extract as an active ingredient.
(27) Drinking water containing 0.01 mg / ml to 30 mg / ml of a water-soluble sweet potato shoot extract as a polyphenol content.
(28) (1), (2), (3), (4), (5), (6), (7), (13), (14), (15), (16), (17) ) Or a food or drink containing the water-soluble sweet potato stem and leaf extract according to (18).
(29) Soft drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, tea drinks, concentrated drinks, nutrition drinks, alcoholic drinks, fats and oils, processed foods, noodle breads, seasonings, confectionery (water confectionery, jelly, The food or drink according to (27) or (28) above, which is a yogurt, gummi) or nutritional supplement.
ADVANTAGE OF THE INVENTION According to this invention, the polyphenol containing water-soluble sweet potato stalk-and-leaf extract which has various beneficial activity for a human body can be provided. Since the extract of the present invention is water-soluble, there is an advantage that it can be ingested after being dissolved in various beverages, for example.
Moreover, according to the method for producing a polyphenol-containing sweet potato foliage extract of the present invention, a polyphenol-containing extract can be efficiently obtained without using special materials or facilities.
Furthermore, the sweet potato foliage extract of the present invention has activities or actions such as antioxidant activity, tyrosinase inhibitory activity, hepatoprotective action, sugar and neutral fat absorption inhibiting action, etc., and thus functions having such activity or action. It is useful as a functional food, drink, functional material, medicine, and the like.

FIG. 1 is a liquid chromatography chart of a sweet potato stem and leaf extract obtained from the stem and leaf of sweet potato.
FIG. 2 is a liquid chromatography chart of a sweet potato stem and leaf extract obtained from sweet potato leaves.
FIG. 3 is a graph showing the antioxidant effect of a sweet potato shoot extract in the rat liver injury model administered with APPH in Example 9. (A) shows the measurement result of urinary 8-OHdG, and (b) shows the measurement result of thiobarbituric acid reactant (TBARS) in the liver homogenized sample.
FIG. 4 is a graph showing the sugar absorption inhibitory action of sweet potato stem and leaf extract in the rat sugar tolerance test of Example 11.
FIG. 5 is a graph showing the results of a comparison test with the guava leaf extract on the blood glucose elevation inhibitory effect of Example 11.
6 is a graph showing the neutral fat absorption inhibitory action of sweet potato stem and leaf extract in the rat fat tolerance test of Example 12. FIG.
FIG. 7 is a graph showing the results of a comparative test with the green tea extract for the fat absorption inhibitory effect of Example 12.
FIG. 8 is a graph showing the deodorizing effect of the sweet potato foliage extract of Example 16. The results for ammonia (a), mercaptan (b), and trimethylamine (c) are respectively shown.
FIG. 9 shows the state of fat cells of Example 17.
10 is a graph showing the average time of EDB and IMO of mice in the forced swimming test of Example 18. FIG.
FIG. 11 is a graph showing the deterioration time of fats and oils at the concentration of the stem and leaf extract of sweet potato of Example 19.

Hereinafter, the present invention will be described in detail.
(Polyphenol-containing water-soluble sweet potato stem and leaf extract)
The 1st aspect of this invention is a water-soluble extract derived from a sweet potato foliage, Comprising: It is related with the sweet potato foliage extract characterized by including polyphenol. In the present specification, “sweet potato” refers to a plant belonging to the genus Sweet potato of the convolvulaceae family, and any variety can be used as long as it belongs to this genus, such as white yutaka, koganesengan, SUKUH, purple tanegashima, potato potato Among them, the sweet potato of the variety belonging to white sweet potato is preferable. White sweet potato refers to sweet potatoes whose white root skin is almost free of anthocyanins and is white. More preferred is Shiroyutaka. In the present specification, “sweet potato foliage” is used to mean a material containing at least leaves, preferably both foliage, of the above-ground part of sweet potato. Especially preferred are leaves only. Since sweet potato foliage is usually discarded for no use, the use of such materials is also significant in terms of resource reuse. The sweet potato foliage used here may be a fresh material or a dry material. A dry material is preferred, and as a drying method, suitable means such as sun drying, hot air drying, freeze drying and the like can be selected as appropriate, but sun drying is preferable. The sweet potato stems and leaves can be crushed in consideration of extraction efficiency. It is also possible to increase the taste and flavor of the extract by appropriately roasting the sweet potato stems and leaves. Since the sweet potato stem and leaf extract of the present invention is water-soluble, there is an advantage that it can be taken and dissolved in various beverages, for example. Here, “water-soluble” means that at least 100 mg, preferably 1 g, more preferably 10 g, particularly preferably 50 g or more can be dissolved in 1 L of water at room temperature.
The sweet potato foliage extract of the present invention contains a polyphenol derived from sweet potato foliage as an active ingredient. The sweet potato stem and leaf extract of the present invention is preferably 10% or more, preferably 15% or more, more preferably 20% or more, still more preferably 25% or more, particularly preferably 30% or more of the total nonvolatile component weight in terms of catechin. Of polyphenols. The upper limit of the polyphenol content is not particularly limited, but the sweet potato shoot extract of the present invention usually contains up to about 60% polyphenol. The polyphenol content may be expressed in terms of gallic acid. Examples of the polyphenol component derived from the stem and leaves of sweet potato include quercetin glycosides such as quercetin-3-glucoside and quercetin-3-galactoside, chlorogenic acid, 3,4-dicaffeoylquinic acid, and 3,5-dicaffeoyl Examples thereof include caffeic acid derivatives such as quinic acid, 4,5-dicaffeoylquinic acid, and 3,4,5-tricaffeoylquinic acid. In addition, in the polyphenol derived from the stem and leaves of sweet potato, an unidentified polyphenol component may be contained, but the present invention does not exclude such an unidentified polyphenol component. Among the polyphenols, quercetin-3-glucoside is a preferable polyphenol component because of its good absorption into the body (Oltof MR. Et al., J Nutr. 2000 May; 130 (5): 1200-1203, Morand C. et al., Free Radical Res. 2000 Nov; 33 (5): 667-76.). Therefore, in a preferred embodiment of the present invention, the water-soluble sweet potato extract of the present invention has at least quercetin-3-glucoside as a constituent component of the polyphenol component in the water-soluble sweet potato stem and leaf extract, and more preferably Are preferably those containing quercetin-3-glucoside and 3,5-dicaffeoylquinic acid. More preferably at least quercetin-3-glucoside, chlorogenic acid and 3,5-dicaffeoylquinic acid, particularly preferably at least quercetin-3-glucoside, quercetin-3 galactoside, chlorogenic acid and 3,5-dicaffeic acid It is desirable to contain oil quinic acid. It is desirable that the content of quercetin-3-glucoside in the polyphenol is 1% or more, preferably 2% or more, more preferably 3% or more, particularly preferably 5% or more in the sweet potato extract. The upper limit of the quercetin-3-glucoside content is not limited, but the sweet potato shoot extract of the present invention usually contains up to about 30% quercetin-3-glucoside in the polyphenol. Sweet potato leaves contain a lot of quercetin glycosides such as quercetin-3-glucoside and -galactoside, so if you extract using a raw material with a high percentage of leaves, you get a fraction that contains a lot of quercetin glycosides be able to. Quercetin-3-galactoside has been heretofore unknown as a component of sweet potato foliage and is one of the components that characterize the sweet potato foliage extract of the present invention. The content of 3,5-dicaffeoylquinic acid in the polyphenol is preferably 1% or more, more preferably 2% or more, and particularly preferably 3% or more. It is also desirable to contain chlorogenic acid. Moreover, the sweet potato shoot extract of this invention may contain subcomponents, such as amino acids, such as phenylalanine and a tryptophan, organic acids, polysaccharides, and glycolipids other than polyphenol. Examples of organic acids include quinic acid, polysaccharides include, for example, oligosaccharides, and glycolipids include, for example, yarapine. Components other than these polyphenols are also preferable constituents of the sweet potato stem and leaf extract of the present invention. . Quantification of these polyphenol components or subcomponents can be performed, for example, by high performance liquid chromatography (HPLC).
The production method of the sweet potato foliage extract of the present invention is not particularly limited. From the viewpoint of extraction efficiency, extraction with a water-containing organic solvent described later is preferable, but it can also be obtained by water extraction. Hot water, hot water, or cold water can be used for water extraction, and the target components are extracted by putting the foliage in water at a target temperature and immersing it for a certain period of time. The foliage is preferably dried and crushed in advance. As extraction temperature, for example, in the case of hot water, 60-100 ° C, preferably 60-80 ° C, in the case of hot water, 30-60 ° C, preferably 50-60 ° C, in the case of cold water, 0-30 ° C, preferably Although it is 10-30 degreeC, the hot water extraction is preferable from the point of extraction efficiency. The extraction time is not particularly limited, but in the case of hot water, it is 10 to 150 minutes, preferably 20 minutes to 70 minutes. It is preferable to extract over a long time as the extraction temperature is lowered. Can also be extracted over a day. Further, the extraction can be performed under pressure during extraction, and it is desirable to perform the extraction under pressure particularly when the extraction temperature is lowered. After extraction, the extract can be cooled to remove the precipitate and obtain a sweet potato shoot extract. For drip extraction, place the foliage on a cloth or paper filter, pour hot water from above, and filter. It can be selected as appropriate according to the desired taste, flavor and aroma. In addition, the purification process described later may be added, but before the purification by the column, a step of diluting the extract, or an accelerator for removing the precipitate (organic acid, ethanol, etc.) is added when removing the precipitate. It is desirable to add a process for facilitating column purification, such as a process of performing the process. The obtained aqueous solution of sweet potato foliage extract may be further concentrated and used, or may be dried to remove water to obtain a powdery sweet potato foliage extract.
(Production method of sweet potato stem and leaf extract and extract obtainable by the production method)
The second aspect of the present invention includes a step of extracting sweet potato stems and leaves with a water-containing organic solvent, a step of removing the organic solvent from the extract obtained by the extraction step to obtain a water fraction, and purifying polyphenol from the water fraction. The present invention relates to a method for producing a polyphenol-containing sweet potato shoot extract characterized by comprising a step. The third aspect of the present invention relates to a sweet potato foliage extract obtainable by this production method.
Hereinafter, preferred embodiments of the respective steps in the production method of the present invention will be described.
(Extraction process)
First, in the production method of the present invention, sweet potato foliage is subjected to extraction using a water-containing organic solvent. As described above, the sweet potato foliage used here may be a fresh material or a dry material, and is preferably pulverized in consideration of extraction efficiency. The extraction method used here is not particularly limited, and a known method such as cooling, digestion or refluxing can be used under standing or stirring conditions. For example, a water-containing organic solvent is added to a crushed dried sweet potato foliage, they are mixed, and extracted while being immersed or heated under reflux. The amount of the water-containing organic solvent to be added is not particularly limited, but when using a dry material, add a water-containing organic solvent having a capacity of at least 3 times the volume of the material, and when using a fresh material, a volume of at least 5 times the volume of the material. Is desirable.
Here, the water-containing organic solvent used for extraction is not particularly limited as long as it can extract polyphenols from sweet potato stalks and leaves. For example, a mixed solution of water and a hydrophilic organic solvent is used. The organic solvent content in the mixed solution is, for example, 40 to 90% by volume, preferably 40 to 80% by volume, and more preferably 50 to 80% by volume. Examples of the hydrophilic organic solvent include monovalent lower alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and t-butanol; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and the like. Polyhydric alcohols; cellosolves such as methyl cellosolve and ethyl cellosolve; ethers such as dioxane and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone. In the present invention, water-containing alcohols (ethanol, methanol, etc.) can be particularly preferably used. The present inventors have found that the extracted polyphenols decompose and disappear with time when the water content of the hydrous alcohol that is the extract at the time of extraction is large. In addition, when the alcohol concentration is too high, the yield decreases, and the smell and taste tend to deteriorate. That is, the hydrous alcohol (for example, ethanol) used in the extraction step of the present invention is preferably 40 to 90% by volume, more preferably 50 to 80% by volume of alcohol (for example, ethanol). In particular, 60% by volume or more of ethanol is desirable. The extraction as described above is performed, for example, at 10 to 70 ° C., preferably 40 to 60 ° C., for 1 hour to 48 hours, preferably 2 hours to 10 hours.
Next, the organic solvent is removed from the extract obtained as described above to obtain a water fraction. The method for removing the organic solvent can be used by those skilled in the art depending on the type of hydrous organic solvent used, such as distillation of the organic solvent by concentration under reduced pressure, fractionation of the organic solvent with a non-hydrophilic organic solvent (eg, hexane, etc.). The method can be selected as appropriate. When hydrous ethanol is used, the alcohol is preferably distilled off by concentration under reduced pressure. The removal of the organic solvent is preferably performed until the ratio of water in the solution is at least 70%. The extract obtained by removing the organic solvent thus obtained will be referred to as a water fraction. In the step of obtaining the water fraction, components that are insoluble or hardly soluble in water are precipitated or fractionated, so that the water fraction is in a state where sweet potato stem and leaf components that are insoluble in water are removed. Therefore, it is considered that this step contributes to increase the water solubility of the sweet potato shoot extract of the present invention. In order to promote precipitation of components that are insoluble or hardly soluble in water, the water fraction may be allowed to stand or an operation of adding several times the amount of water may be performed. The precipitated water-insoluble or hardly soluble component may be removed by an appropriate means such as removal by decantation, fractionation by non-hydrophilic organic solvent (eg, hexane etc.), filtration.
(Purification process)
Next, the polyphenol of the water fraction obtained as described above is purified. Purifying polyphenol here means increasing the proportion of polyphenol in the total content of non-volatile components in the sample. Specifically, purification can be achieved by removing various nonvolatile components other than polyphenols from the water fraction. In the finally obtained sweet potato stem and leaf extract (usually in the form of a powder from which volatile components such as water have been removed), the content of polyphenols in all non-volatile components is 10% or more, preferably 20% or more. If so, the polyphenol fraction shall be purified. For purification, that is, removal of non-volatile components other than polyphenol, a known method such as a method using an adsorbent is used. For example, polyphenol is adsorbed on the adsorbent by passing the above water fraction through a column packed with an adsorbent capable of selectively adsorbing and eluting polyphenols, and purified polyphenol is eluted with an eluent after washing. A batch method may be used instead of the column. Alternatively, a method may be used in which a hydrophilic organic solvent such as ethanol is added to the water fraction to precipitate and remove non-volatile components (such as polysaccharides) that are hardly soluble in the organic solvent. A combination of such precipitation removal method and column purification may be used.
As the adsorbent used here, for example, a synthetic adsorption resin of a crosslinked styrene-based porous polymer, an anion exchange resin, octadecyl group chemically bonded silica gel (ODS), or the like can be used. Examples of commercially available synthetic resin adsorbents include, for example, Diaion HP-20, HP-21, HP2MG, SP207, SP825, SP850 from Mitsubishi Kasei Corporation; Amberlite XAD-2, XAD-4 from Rohm and Haas XAD-7, XAD-26, and the like can be used. Conditions for carrying out the purification method using the adsorbent can be easily set by those skilled in the art. When a manual is attached to a commercially available adsorbent, the adsorption operation can be performed according to the instructions of the manual.
After the adsorption, impurities and the like are usually washed and removed by passing a washing solution through the column. As the cleaning liquid, water (preferably distilled water), 1 to 10% by weight ethanol aqueous solution, or the like is suitably used. Usually, it is better to pass a cleaning solution of about 1 to 10 times the amount of resin. After washing, the polyphenol-containing fraction can be eluted and collected by passing the eluate through a column. As the eluent, for example, a water-containing organic solvent such as water-containing alcohol, water-containing acetone, water-containing acetonitrile or the like can be used. A particularly suitable eluent is 20% or more of an aqueous ethanol solution or 100% ethanol. Usually, the flow rate of the eluate is preferably about 2 to 6 times the amount of resin.
The polyphenol-containing fraction thus obtained is concentrated under reduced pressure (or concentrated to dryness) to distill off the organic solvent, whereby an aqueous solution of sweet potato stem and leaf extract can be obtained. Further, the water content of the aqueous solution of the sweet potato shoots and leaves extract is removed by spray drying or freeze drying to obtain a powdered sweet potato shoots and leaves extract. If necessary, the powder may have a uniform particle size using a pulverizer or may be a fine powder. Further, powder auxiliary agents such as dextrin can be added for spray drying or freeze drying, and stabilizers, excipients, and the like can be added to the obtained powder. The composition thus obtained, that is, a liquid preparation or a powder preparation, contains a sweet potato foliage extract-containing functional food and drink, a functional material, a pharmaceutical preparation, an antioxidant, a hepatoprotectant, a tyrosinase inhibitor, It can be used as a sugar absorption inhibitor, a neutral fat absorption inhibitor, a prophylactic / therapeutic agent for obesity, an antidepressant, an anti-fatigue agent, a deodorant, an oil and fat, and a food containing fat and oil.
The third aspect of the present invention is a sweet potato foliage extract obtainable by the above production method. If it is the same as a sweet potato foliage extract obtained by the said manufacturing method, even if it is obtained by a different manufacturing method, it is contained in the sweet potato foliage extract of this invention. Whether or not they are the same can be confirmed by, for example, whether or not they have the characteristics described in the first aspect of the present invention. That is, a preferred form of the sweet potato shoot extract obtainable by the above production method is the water solubility, polyphenol content, polyphenol component, polyphenol which can be obtained by the above production method and described in the first aspect of the present invention. It is a sweet potato stem and leaf extract characterized by the content of various components in it.
(Use)
According to a fourth aspect of the present invention, there is provided a pharmaceutical, a functional food / beverage product, a functional material, an antioxidant, a liver comprising the sweet potato foliage extract described in the first aspect or the third aspect of the present invention as an active ingredient. Contains protective agent, tyrosinase inhibitor, sugar absorption inhibitor, neutral fat absorption inhibitor, prevention / treatment agent for obesity, prevention / treatment agent for metabolic syndrome, antidepressant, anti-fatigue agent, deodorant, fats and oils It relates to food deterioration inhibitors. Furthermore, it is related with the food / beverage products containing the said sweet potato stem and leaf extract. As the method for producing the sweet potato foliage extract used here, the above production method is preferable, but the method is not particularly limited, and any known method can be used. A preferred embodiment of the sweet potato foliage extract used here is a sweet potato foliage extract having the characteristics described in the first aspect or the third aspect of the present invention.
1. Antioxidant
The antioxidant ability of the sweet potato shoot extract of the present invention has been confirmed by various antioxidant ability experiments in Example 8 described later. Therefore, the sweet potato shoot extract of this invention can be used as an active ingredient of an antioxidant.
It has been confirmed that the antioxidant of the present invention has an action of eliminating active oxygen even in vivo by an experiment using the rat of Example 9. Therefore, the antioxidant of the present invention can be used for the prevention or treatment of various diseases and symptoms involving active oxygen. Diseases involving active oxygen include diseases that involve lipid peroxides such as cancer, allergy, and arteriosclerosis that can be induced by active oxygen. Symptoms involving active oxygen include various symptoms associated with aging, spots, wrinkles, rough skin, and the like.
2. Hepatoprotectant
The hepatoprotective action of the sweet potato foliage extract of the present invention has been confirmed by experiments using rats of Example 9 described later. Therefore, the sweet potato foliage extract of the present invention can be used as an active ingredient of a hepatoprotectant.
The hepatoprotective agent of the present invention can be used for the prevention or treatment and amelioration of diseases and symptoms associated with insufficiency or decline in liver function. Examples of such a disease associated with liver function failure or reduction include liver cirrhosis, viral hepatitis, fulminant hepatitis, liver cancer such as liver cancer, liver damage and exhaustion, and the like. Symptoms related to liver function failure or decline include hangover, alcoholic hepatitis, malaise, fatigue, poor circulation, and the like. In order to prevent these diseases and symptoms, it is preferable to improve the liver function by ingesting the hepatoprotective agent of the present invention in advance or during normal times.
3. Tyrosinase inhibitor
It has been confirmed by the tyrosinase inhibitory activity test described in Example 10 below that the sweet potato shoot extract of the present invention has tyrosinase inhibitory activity. Tyrosinase, also called polyphenol oxidase, is an enzyme that inactivates polyphenols and exacerbates skin melanogenesis and food browning. Therefore, the sweet potato shoot extract of the present invention can be used as an active ingredient of a tyrosinase inhibitor.
The tyrosinase inhibitor of the present invention can be used for the prevention or treatment and amelioration of diseases and symptoms involving tyrosinase. Examples of symptoms involving such tyrosinase include skin melanin generation, sunburn, and pigmentation. Moreover, by ingesting the tyrosinase inhibitor of the present invention, the generation of melanin in the skin can be suppressed, and a whitening effect can be expected. Therefore, the sweet potato foliage extract of the present invention can also be used as an active ingredient in cosmetics or functional foods having a whitening effect.
4). Sugar absorption inhibitor
It has been confirmed by experiments using rats described in Example 11 described later that the sweet potato extract of the present invention has a sugar absorption inhibitory action. Therefore, the sweet potato foliage extract of the present invention can be used as an active ingredient of a sugar absorption inhibitor.
Since the sugar absorption inhibitor of the present invention has the action of suppressing sugar absorption and suppressing an increase in blood sugar level, it can be used for the prevention or treatment and improvement of diseases and symptoms related to sugar ingested in the human body. it can. Examples of such diseases involving sugars include diabetes, obesity, diabetic complications, and the like. Moreover, since the sweet potato foliage extract of this invention has the effect which prevents the hyperglycemia after a meal, it can become a functional food material with appeal to the person who is worried about a blood glucose level.
5. Neutral fat absorption inhibitor
It has been confirmed by experiments using rats described in Example 12 that the sweet potato stem and leaf extract of the present invention has a neutral fat absorption inhibitory action and an absorption delay action. Therefore, the sweet potato shoot extract of this invention can be utilized as an active ingredient of a neutral fat absorption inhibitor.
Since the neutral fat absorption inhibitor of the present invention has an action of suppressing neutral fat absorption, it can be used for the prevention or treatment and improvement of diseases and symptoms associated with an excess of neutral fat. Examples of such diseases include hypercholesterolemia, hyperlipidemia, ischemic heart disease, cerebrovascular disorder and the like. Moreover, the sweet potato foliage extract of this invention can become a functional food material with appeal to the person worried about body fat.
6). Obesity prevention / treatment agent
The sweet potato foliage extract of the present invention has an adipocyte differentiation and hypertrophy inhibitory effect, as confirmed by the in vitro rat mesentery-derived white adipocyte differentiation and hypertrophy suppression test described in Example 17. Yes. Therefore, the sweet potato foliage extract of the present invention can be used as an active ingredient of an adipocyte differentiation and hypertrophy inhibitor, and therefore can be used as a prophylactic / therapeutic agent for obesity. Furthermore, since the sweet potato stem and leaf extract also has the above-described sugar absorption inhibitory action and neutral fat absorption inhibitory action, the synergistic effect of these actions can be expected to prevent and treat obesity.
The prophylactic / therapeutic agent for obesity of the present invention can be used for the prevention or treatment and improvement of diseases and symptoms associated with obesity. Examples of such diseases include arteriosclerosis, hypertension and diabetes. Moreover, the sweet potato foliage extract of this invention can become a functional food material appealing to the person worried about obesity and body fat.
7). Prevention and treatment of metabolic syndrome
As described above, the sweet potato stem and leaf extract of the present invention can prevent and ameliorate hyperglycemia symptoms by suppressing sugar absorption, and can prevent and ameliorate hyperlipidemia, especially hypertriglycerideemia, by suppressing neutral fat absorption. Thus, it can also be used as an active ingredient of a preventive / therapeutic agent for metabolic syndrome because it has an action for preventing / treating obesity due to an action of inhibiting adipocyte differentiation and hypertrophy. Metabolic syndrome is mainly due to the accumulation of visceral fat, and multiple risk factors such as obesity, diabetes, hyperlipidemia, and hypertension accumulate, resulting in arteriosclerosis and coronary artery disease (final events such as myocardial infarction and brain It refers to a condition that increases the risk of developing (infarction). This is one of the diseases that are regarded as a problem in modern society where various lifestyle-related diseases tend to develop due to disturbance of eating habits. Since the sweet potato stem and leaf extract of the present invention has a plurality of actions effective for preventing and improving metabolic syndrome, it can be a functional food material appealing to those who are concerned about metabolic syndrome.
8). Antidepressant
It has been confirmed by examination of the antidepressant action by the mouse forced swimming method described in Example 18 that the sweet potato foliage extract of the present invention has an antidepressant action. Therefore, the sweet potato shoot extract of this invention can be utilized as an active ingredient of an antidepressant. It also reduces stress and can be expected to relax.
Since the antidepressant of the present invention has an antidepressant action, it can be used for prevention or treatment and amelioration of depression and symptoms associated with depression. In addition, the sweet potato shoot extract of the present invention can be a functional food material that has appealing power for people who are concerned about depression and modern people with much stress.
9. Anti-fatigue
It has been confirmed by the examination of the anti-fatigue action by the mouse forced swimming method described in Example 18 that the sweet potato stem and leaf extract of the present invention has an anti-fatigue action. Therefore, the sweet potato shoot extract of this invention can be utilized as an active ingredient of an anti-fatigue agent.
For example, it is expected to prevent, reduce, and improve physical and mental fatigue, such as reducing physical fatigue caused by prolonged exercise, and relaxing mood to make it difficult to feel mental stress and fatigue. . The sweet potato foliage extract of the present invention can be a functional food material that appeals to athletes who are constantly subject to physical fatigue, and those who are likely to feel physical and mental fatigue due to long working hours.
10. Deodorants
It has been confirmed by the test described in Example 16 that the sweet potato stem and leaf extract of the present invention has a deodorizing effect on causative substances such as bad breath, body odor, and fecal odor of humans and pets. Therefore, the sweet potato foliage extract of the present invention can be used as an active ingredient of a deodorant.
Sweet potato stem and leaf extract can be used for deodorizing human and pet bad breath, body odor, fecal odor, food and drink, etc., and it can be used in a very wide range of applications among deodorizing substances. Can be a substance.
11. Deterioration preventive agent for oils and fats and oil-containing foods
It has been confirmed by the oil and fat stability test described in Example 19 that the sweet potato foliage extract of the present invention is effective in preventing the deterioration of oils and fats and oil-containing foods. Therefore, the sweet potato foliage extract of the present invention is useful as a deterioration preventing agent that suppresses the deterioration of fats and oils, and particularly as a deterioration preventing agent for animal fats and oils. It can be added to various types of fats and oils, including processed foods (fried potatoes, snacks, cup noodles, etc.) that use animal lipids such as pork fat and lard, and can be applied to prevent the deterioration of fats and oils. In order to prevent the deterioration of food fats and oils, it is possible to add powdery sweet potato stem and leaf extract to the fats and oils, or to mix and emulsify an aqueous solution of the sweet potato stem and leaf extract into the fats and oils. In addition, by adding powdered sweet potato foliage extract to deep-fried clothing such as tempura flour, bread crumbs, flour, etc., or mixing it into food ingredients processed with fats and oils, the food is cooked with fats and oils and fats deteriorate. Can also be prevented. The amount added to the food fat is not particularly limited, but is preferably 10 ppm or more, more preferably 200 ppm or more, and particularly preferably 500 ppm or more. The upper limit is not limited, but the sweet potato stem and leaf extract is processed into soft capsules, and 50 It is also possible to add a sweet potato stover extract of about% by weight.
12 Pharmaceuticals, functional foods and drinks and functional materials
The sweet potato foliage extract of the present invention has activities or actions such as antioxidant activity, hepatoprotective action, tyrosinase inhibitory activity, sugar and neutral fat absorption inhibitory action, etc., and has an excellent function as a functional material. . Therefore, the sweet potato shoot extract of this invention can be utilized as an active ingredient of a functional material.
The functional material can be used for various purposes as a functional material and raw material. The form is not particularly limited, and the active ingredient may be only the sweet potato stem and leaf extract, or may be in a state mixed with other functional materials and raw materials. It can take. In Example 20, it was confirmed that granules, tablets and gummi were produced from sweet potato foliage extract as a raw material, and were easy to use as a functional material.
Daily intake that is expected to be effective in food applications as a functional material is 0.1 mg / kg or more per day for an adult, preferably 1 mg / kg or more, more preferably 10 mg / kg or more, and particularly preferably 30 mg / kg. That's it. Although the upper limit of the daily intake is not particularly limited, for example, it is within an allowable range up to about 2000 mg / kg. However, the range of preferable intake may naturally vary depending on the product form and individual characteristics.
As a functional material, it can be used for food antioxidants, food pigment stabilizers, deodorants and the like because it has an antioxidant effect as a use other than ingestion as food. Moreover, since it has tyrosinase inhibitory activity, utilization as cosmetics can be considered. The cosmetic can be produced according to a conventional method. Cosmetics are not limited to general skin cosmetics, but include quasi-drugs, designated quasi-drugs, external medicines, etc., and the dosage form is arbitrarily selected according to the purpose. be able to. That is, dosage forms such as creams, ointments, emulsions, solutions, gels, and forms such as packs, lotions, powders, and sticks can be used. The blending amount of the extract is preferably 0.0001 to 1.0%, particularly preferably 0.001 to 0.1% in terms of component solid content, based on the total amount of the cosmetic.
The functional food or drink comprising the sweet potato foliage extract of the present invention as an active ingredient is provided by formulating the sweet potato foliage extract of the present invention into an appropriate formulation or adding it to the food or drink. The pharmaceutical which uses the sweet potato foliage extract of this invention as an active ingredient is provided by formulating the sweet potato foliage extract of this invention in a suitable formulation.
Oral forms such as powders, granules, capsules, pills, tablets and other solid preparations, liquids such as liquids, suspensions and emulsions, etc. An administration agent is mentioned. This orally-administered agent is an excipient, disintegrant, binder, lubricant, surfactant, alcohol, water, water-soluble polymer, sweetener, flavoring agent generally used depending on the form of the orally-administered agent. In addition, it can be produced by adding a sour agent or the like. The sweet potato shoot extract varies depending on the use and form in the preparation for oral administration, but is generally contained in an amount of 0.1 to 100% by weight, particularly 1 to 80% by weight.
In addition, when the sweet potato foliage extract of the present invention is administered as a pharmaceutical, its dosage varies depending on its action, target disease, administration subject, administration route, etc. For example, in an adult generally weighing 60 kg, The content is about 1 mg to 2000 mg per day, preferably about 10 mg to 500 mg, more preferably 30 mg to 300 mg.
When a functional food or drink is provided by adding a sweet potato foliage extract to a food or drink, the sweet potato foliage extract is added to food or beverage so as to exhibit its functionality. The sweet potato foliage extract of the present invention has the property of suppressing excessive absorption of carbohydrates and neutral fat in the diet and production of lipid peroxide in the liver, and is also promising for a calorie diet. Products containing a lot (fruit juice, juice, beer, alcoholic beverages, chocolate, cookies, honey products, strawberries, gum, jelly, ice cream, yogurt, Japanese confectionery / Western confectionery), raw materials rich in neutral fat (fish oil, margarine, dairy products) Processed foods using butter, egg yolk oil, mayonnaise, salad oil, dressing), fried food products that generate a large amount of lipid peroxide (tempura, potato chips and other snacks, fried rice crackers, instant noodles), and sugar / neutral Ingredients that reduce fat absorption and decrease body fat (green tea, mulberry leaf tea, guava, tomorrow, soy protein, soy milk, chitin, chitosan, a Gin acid, it is effective to mix the oligosaccharide-dextrin dietary fiber) functionality enhancement for products using. Furthermore, umami, isomerized linoleic acid, sesamin, vitamin E, CoQ10, alpha lipoic acid, carnitine, amino acids (valine, leucine, isoleucine, arginine, theanine, histidine), ginseng (Ezocogi, Red ginseng, Western ginseng), organic Acids (vitamin C, vinegar, citric acid), vitamin B group, sardine, ants, placenta, pepper, black pepper, carotenoids (lycopene, astaxanthin, lutein), isoflavones, mushrooms, seaweed-derived polysaccharides (Agaricus, fucoidan), Nutritional supplements that combine substances selected from various herbs (ginkgo leaves, pine bark, grape extract), berries (blueberries), and lipids (EPA, DHA) are also effective. As an addition amount to foods, beverages, etc., it is preferable to contain so that the daily intake of the sweet potato stem and leaf extract is 1 mg / kg or more, preferably 30 mg / kg or more per adult day. Although the upper limit of the daily intake is not particularly limited, for example, it is within an allowable range up to about 2000 mg / kg. However, the range of preferable intake may naturally vary depending on the product form and individual characteristics.
13. Food and drink
The water-soluble sweet potato foliage extract of the present invention has a polyphenol content of 0.001 mg / ml to 30 mg / ml, preferably 0.01 mg / ml to 30 mg / ml, more preferably 0.01 mg / ml to 10 mg / ml, most Preferably, it can be used as a food or drink containing 0.01 mg / ml to 3 mg / ml. According to the present invention, it is possible to increase the polyphenol content in the sweet potato stem and leaf extract, and therefore, it is possible to obtain a drinking water containing polyphenols derived from sweet potato stem and leaf at a high concentration. In terms of palatability, the polyphenol content is desirably about 3 mg / ml or less, and in order to exert the medicinal effects / functions of the sweet potato stem and leaf extract, it is efficient to contain about 0.01 mg / ml or more. It is. From these points, more preferably 0.05 mg / ml to 2.5 mg / ml, still more preferably 0.1 mg / ml to 2.5 mg / ml, and particularly preferably 0.3 mg / ml to 2 mg / ml. The amount can be appropriately increased or decreased depending on the type of food or drink to be processed. In addition, the sweet potato stem and leaf extract aqueous solution can be processed into jelly and other sweets, the sweet potato stem and leaf extract powder can be mixed with processed foods such as noodles and instant foods, and can be used as a dietary supplement. . Food and drink products include soft drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, tea drinks, concentrated drinks, nutrition drinks, alcoholic drinks, fats and oils, processed foods, noodle breads, seasonings, confectionery (water confectionery, Jelly, yogurt, gummi), dietary supplements, and the like. It is preferable that the amount of polyphenol derived from sweet potato foliage per time is adjusted to about 1 mg to 2000 mg, preferably about 5 mg to 500 mg, more preferably about 10 mg to 300 mg.

表１からわかるようにエタノール濃度４０％以上であればポリフェノールが３００ｍｇ以上抽出されていることがわかる。また、乾固重量あたりのポリフェノール重量の割合についてはエタノール濃度６０％が最大で２３．６％となった。
次に抽出液中のポリフェノールの安定性を調べた。安定性については抽出直後のポリフェノール濃度と１２日間室内に放置した後のポリフェノール濃度を比較し濃度の低下率を安定性の指標とした。結果を表２に示す。

表２からわかるようにエタノール濃度が低下すると１２日後のポリフェノール濃度が低下することが分かった。このことから抽出液については少なくとも４０％以上、好ましくは６０％以上のエタノール濃度が適当であると考えられる。また、エタノール濃度が高い場合（８０％）は葉緑素などの成分や油分なども抽出されることが観察され、かつポリフェノールの収量も若干低下することを考慮すると、８０％より高いエタノール濃度で抽出を行うことは利点がないと思われる。
実施例２ ポリフェノールの純度向上法の検討
機能性食品において機能性成分の純度を、コストをかけずに上げることは重要なことである。例えば不純物の中に渋みなど、好ましくない成分が含まれている場合があり、純度を上げることにより、相対的に好ましくない成分を少なくできるからである。そこで、サツマイモの茎と葉に分けて抽出を実施し、さらに濃縮後、時間とともに発生する沈殿を除去する方法を検討した。検討条件として、下記の項目で検討した。
（ａ）サツマイモの茎を分離し、６０％エタノールを用いた実施例１の手法でポリフェノール画分を得、その画分の乾固重量あたりのポリフェノール量つまり純度を調べた。ただし、実施例１のヘキサン分画は省略した。
（ｂ）サツマイモの葉を分離し、６０％エタノールを用いた実施例１の手法でポリフェノール画分を得、その画分の乾固重量あたりのポリフェノール量つまり純度を調べた。ただし、実施例１のヘキサン分画は（ａ）と同様省略した。
（ｃ）サツマイモの葉を分離し、６０％エタノールを用いた実施例１の方法で抽出し、２００ｍｌの濃縮液を得、その濃縮液を３日間静置した後、３日間で生成した沈殿を除去したものをＨＰ−２０カラムに通し実施例１と同じようにポリフェノール画分を捕集した。そして、その画分の乾固重量あたりのポリフェノール量つまり純度を調べた。ただし、実施例１のヘキサン分画は（ａ）と同様省略した。
（ｄ）サツマイモの葉を分離し、６０％エタノールを用いた実施例１の方法で抽出し、２００ｍｌの濃縮液を得、その濃縮液に約４倍容量のエタノールを加え３日放置した。３日間で生成した沈殿を除去した後、再びロータリーエバポレーターでエタノールを除去した後、ＨＰ−２０カラムに通し実施例１と同じようにポリフェノール画分を捕集した。そして、その画分の乾固重量あたりのポリフェノール量つまり純度を調べた。ただし、実施例１のヘキサン分画は（ａ）と同様省略した。
その結果を表３に示す。

表３からわかるように葉から抽出した場合、ポリフェノール量を茎と比べ１０倍程度効率よく抽出でき、カテキン換算として算出したポリフェノール純度も高いことが分かる。また、実施例１の方法で抽出、濃縮を行った後、静置することで純度が向上することが分かった。また、放置する際に、エタノールを加えた場合の方が純度として５６．４％と高い値になった。このことは（ｃ）の静置する条件ではエタノール濃度が低いため、一部分解、消失を考慮する必要があると考えられる。以上のことから濃縮後に静置処理を行い沈殿の生成を待った後にその沈殿を除去することにより、通常は２０％から３０％のポリフェノール純度（カテキン換算）であるものを６０％程度まで向上可能なことがわかった。
実施例３ 液体クロマトグラフィーによる成分の検索
６０％エタノールを用いた実施例１の手法でサツマイモ茎葉もしくは葉より抽出分画したポリフェノール画分（サツマイモ茎葉抽出物）を液体クロマトグラフィーで成分を検索した。条件を下に示す。
条件：カラム： Ｓｈｉｍａ−ｐａｃｋ ＶＰ−ＯＤＳ（島津製）
カラム温度： ４０℃
溶離液： Ａ液４．５ｍＭクエン酸水：アセトニトリル：イソプロパノール
１００：１０：３
Ｂ液６ｍＭクエン酸水：アセトニトリル：イソプロパノール
１００：４７：３
溶離液勾配： 時間 Ａ／Ｂ
０ｍｉｎ ８５／１５
４０ｍｉｎ ０／１００（リニアグラジェント）
５０ｍｉｎ ０／１００
６０ｍｉｎ ８５／１５（リニアグラジェント）
図１にサツマイモ茎葉から６０％エタノールを用いて実施例１の方法で得たサツマイモ茎葉抽出物の液体クロマトグラフィーのチャートを示した。ピークの解析から、当該抽出物には、ケルセチン−３−グルコシド、ケルセチン−３−ガラクトシド、クロロゲン酸および３種のジカフェオイルキナ酸（３，４−ジカフェオイルキナ酸、３，５−ジカフェオイルキナ酸、４，５−ジカフェオイルキナ酸）が含まれていることが分かった。また、図２にはサツマイモ葉から６０％エタノールを用いて実施例１の方法で得たサツマイモ茎葉抽出物の液体クロマトグラフィーのチャートを示した。葉のみを用いた抽出物においては特にケルセチン−３−グルコシドやケルセチン−３−ガラクシドが多く含まれていることが分かった。
実施例４ ８０％エタノールを用いたサツマイモ茎葉抽出物の製造
以下の手法でサツマイモ茎葉抽出物を製造した。
（１）サツマイモの乾燥茎葉２．２２ｋｇを２０Ｌの抽出器に入れ、８０％のエタノールを１３．２Ｌ加え加温抽出（７５℃）を２時間行い、ヌッチェにより濾過し、抽出液を約１０Ｌ得た。
（２）さらに同様な操作を３度行い。抽出液４０Ｌを得た。抽出液を減圧下約１／７まで濃縮した。
（３）ヘキサン８．０Ｌ加え脂溶性成分を分離した後、ヘキサン層を除去した。
（４）水層部分は、減圧下さらに溶液が約５Ｌ程度になるまで溶媒を留去した。
（５）濃縮溶液に水を５Ｌ加えた。希釈溶液に不純物が下層にたまったため、デカンテーションにより不溶物を除去した。
（６）上澄み液を吸着樹脂（ＨＰ２０）３Ｌに通液した後、水４Ｌにて樹脂を洗浄した。
（７）樹脂から９０％エタノール１０Ｌを用いて吸着物を溶離させた。
（８）溶出液は減圧下溶媒を留去乾固させ、噴霧乾燥機により粉末サンプル５４．４３ｇ（収率２．４５％）得た。
得られた粉末サンプル（サツマイモ茎葉抽出物）のポリフェノール含量はカテキン換算で約３４％、ポリフェノール中のケルセチン−３−グルコシド含量は５．６％であった。また、液体クロマトグラフィーにて実施例３と同様にケルセチン−３−グルコシド、ケルセチン−３−ガラクトシド、クロロゲン酸およびジカフェオイルキナ酸が含まれていることを確認した。
実施例５ ６０％エタノールを用いたサツマイモ茎葉抽出物の製造
乾燥サツマイモ茎葉１．５ｋｇを粉砕し、６．１Ｌの６０％エタノールを添加し２時間以上抽出を行い、１次抽出液を搾汁し３．５Ｌを回収した。１次搾汁液と同量の６０％エタノールを添加し、１２時間以上置いた後、２次抽出液を搾汁し３．３４Ｌを回収した。１次抽出液と２次抽出液を合わせてロータリーエバポレーターで約１／３量（２．３Ｌ）に減圧濃縮した。壁面に付着した油性成分はデカントで除去し、得られた水溶液に２倍量の１００％エタノールを添加し、１２時間以上放置した。沈殿物（多糖類等と思われる）をデカントで除去し、上澄みをロータリーエバポレーターで約１／７量（９９０ｍｌ）に減圧濃縮した。得られた水溶液をＤＩＡＩＯＮ ＨＰ２０（三菱化学）カラムに通した。カラム容量の５倍量の水で洗浄した後、カラム容量の２倍量の９０％エタノールで溶出し、溶出液をスプレードライヤーで乾固し、サツマイモ茎葉抽出物を得た。乾燥茎葉からの抽出物収率は０．６６％、抽出物中のポリフェノール含量は４１．３％、ポリフェノール中のケルセチン−３−グルコシド含量は３．０％であった。また、液体クロマトグラフィーにて実施例３と同様にケルセチン−３−グルコシド、ケルセチン−３−ガラクトシド、クロロゲン酸およびジカフェオイルキナ酸が含まれていることを確認した。
実施例６ 抽出方法の比較
６０％エタノール抽出、熱水抽出、水抽出についてケルセチン−３−グルコシド抽出量の比較を行った。
（１）６０％エタノール抽出
乾燥サツマイモ茎葉を６０％エタノールで抽出し、ロータリーエバポレーターで濃縮後ＨＰ２０カラムにかけ、９０％エタノールで溶出した画分を乾固し、ケルセチン−３−グルコシド抽出量を測定した。
（２）熱水抽出およびエタノール沈殿
乾燥サツマイモ茎葉を９０℃の熱水で抽出し、２倍量の１００％エタノールを添加後、生じた沈殿を除去し、ロータリーエバポレーターで濃縮後ＨＰ２０カラムにかけ、９０％エタノールで溶出した画分を乾固し、ケルセチン−３−グルコシド抽出量を測定した。
（３）熱水抽出
乾燥サツマイモ茎葉を９０℃の熱水で抽出し、ロータリーエバポレーターで濃縮後ＨＰ２０カラムにかけ、９０％エタノールで溶出した画分を乾固し、ケルセチン−３−グルコシド抽出量を測定した。
（４）水抽出
乾燥サツマイモ茎葉を水で抽出し、２倍量の１００％エタノールを添加後、生じた沈殿を除去し、ロータリーエバポレーターで濃縮後ＨＰ２０カラムにかけ、９０％エタノールで溶出した画分を乾固し、ケルセチン−３−グルコシド抽出量を測定した。結果を表４に示す。

ケルセチン−３−グルコシドの抽出量は、６０％エタノールが優れていることが分かった。また、熱水抽出または水抽出は、カラム精製過程で、エタノールに溶けない物質が精製を阻害するので、カラム精製する場合には、工夫を要することが分かった。
熱水抽出によって、大量にエタノールに不溶な成分が抽出される。この物質は、カラム精製過程で、９０％エタノールによって溶出する際に不溶化すると考えられ、カラムを水で洗浄したにもかかわらず、９０％エタノールでの溶出の際に、強固に樹脂に結合して、褐色の色が抜けなくなる。これはカラムの再生に影響すると予想された。ついで、熱水抽出液や水抽出液に２倍量の１００％エタノールを加え、６７％のエタノール濃度にすると、もやもやとした粘着性のある沈殿物が多量に析出した。この沈殿物をろ過した後にカラム精製を実施するとカラムへの色素沈着は観察されなかった。しかしながら、熱水抽出および水抽出にカラム精製過程を加えた製法は、ケルセチン−３−グルコシド抽出量は６０％エタノール抽出に劣り、また、結局エタノールを使用せねばならず、工程削減の効果も得られないので６０％エタノール抽出と比較して、抽出効率の点からは優位性は低いと判断される。
実施例７ 各種サツマイモ品種の茎葉成分の比較
実施例１ないし６で使用したサツマイモ品種シロユタカと、コガネセンガン、ＳＵＫＵＨ、種子島紫およびシモンイモの４品種について茎葉に含まれるポリフェノール成分の比較を行った。シロユタカ、コガネセンガン、ＳＵＫＵＨ、種子島紫は乾燥サツマイモ茎葉を６０％エタノールで抽出しろ過したサンプルをＨＰＬＣ分析に供した。シモンイモについては市販のお茶（茎葉を使用したお茶）を６０％エタノールで抽出しろ過したサンプルをＨＰＬＣ分析に供した。
その結果、シロユタカと他の４品種においてクロマトグラフィーで検出される成分の種類に大きな差はなく、含有される物質の種類は同等であると考えられたが、各成分の含有割合は、品種によって若干異なっている。また、シロユタカ葉のみを用いたサツマイモ葉抽出物は、他の品種の抽出物と比較して、ケルセチン−３−グルコシドを多く含み、望ましいことが分かった。
実施例８ 抗酸化能の確認
サツマイモ茎葉抽出物を用いて抗酸化能を測定した。
（１）スーパーオキシド消去活性
実施例４で得たサツマイモ茎葉抽出物のスーパーオキシド消去活性を電子スピン反応（ＥＳＲ）法で測定した。結果は３．９×１０^４単位／ｇ（Ｊ．Ｂｉｏｌ．Ｃｈｅｍ．，２４４，６０４９（１９６９）に定義された単位）となりサツマイモポリフェノールに抗酸化能があることが確認できた。抗酸化能としては高いレベルであるものの、抗酸化能が非常に高いと言われるピクノジェノール（１．６×１０^５単位／ｇ）と比べると４分の１程度であった。
（２）ＤＰＰＨラジカル消去能
実施例４で得たサツマイモ茎葉抽出物および実施例２で得た茎のみの抽出物または葉のみの抽出物についてＤＨＨＰラジカル消去能を電子スピン反応（ＥＳＲ）法で測定した。実施例４で得たサツマイモ茎葉抽出物は６５３μｍｏｌ／ｇ、実施例２で得た茎のみの抽出物は３０４μｍｏｌ／ｇ、実施例２で得た葉のみの抽出物は１２７３μｍｏｌ／ｇであった（活性は、サンプル１ｇあたりのトロロックスμｍｏｌ相当量で表示）。市販のお茶粉末では５１５μｍｏｌ／ｇ程度と言われており、サツマイモ茎葉抽出物はお茶粉末と同等かそれよりも優れた活性を示した。
（３）ヒドロキシラジカル消去能
実施例４で得たサツマイモ茎葉抽出物および実施例２で得た茎のみの抽出物または葉のみの抽出物について、過酸化水素−２価鉄イオン系にて発生させたヒドロキシラジカルの消去能をＤＭＰＯを用いたスピントラッピング法で測定した。実施例４で得たサツマイモ茎葉抽出物は１０．８ｍｍｏｌ／ｇ、実施例２で得た茎のみの抽出物は１６．８ｍｍｏｌ／ｇ、実施例２で得た葉のみの抽出物は１４．４ｍｍｏｌ／ｇであった（活性は、サンプル１ｇあたりのマンニトールｍｍｏｌ相当量で表示）。市販のお茶粉末では９．３ｍｍｏｌ／ｇ程度と言われており、サツマイモ茎葉抽出物はお茶粉末と同等かそれよりも優れた活性を示した。
実施例９ サツマイモ茎葉抽出物の肝保護作用
サツマイモ茎葉抽出物を食品や飲料で摂取した際に、成分が腸管から吸収され血液に移行し、実際に体内でフリーラジカルを消去できるかどうかについて確認した。サツマイモ茎葉抽出物を投与したラットと非投与のラットを用いてラジカルイニシエーターである２，２’−アゾビスアミジノプロパン二塩酸塩（ＡＡＰＨ）を腹腔に投与し、その影響を調べた。試験の材料と方法を下記に示す。
（ａ）供試動物
種：ラット、系統：ＳＤ、性別：オス、入荷時週齢：６週齢
（ｂ）試験群の設定
コントロール群：５匹、１ｍｇ／ｋｇ投与群：５匹、３０ｍｇ／ｋｇ投与群：５匹
（ｃ）試験項目および方法
・体重、摂餌量測定：サツマイモ茎葉抽出物の投与は７日間とし、一般状態についての観察体重および摂餌量は毎日午前１０から１１時の間に測定した。飼料および給水は自由摂取とした。
・実施例４で得たサツマイモ茎葉抽出物を蒸留水にて溶解し、サツマイモ茎葉抽出物の摂取量が１日あたり１ｍｇ／ｋｇ、または３０ｍｇ／ｋｇとなるよう胃ゾンデを用いて経口投与した。Ｃｏｎｔｒｏｌ群については生理食塩水を１０ｍＬ／ｋｇを投与した。７日目の投与においては、ＡＡＰＨ投与１２時間前にサツマイモ茎葉抽出物および生理食塩水を投与した。
・ＡＡＰＨの投与は生理食塩水を用いて５０ｍｇ／ｋｇ Ｂ．Ｗに調製し、ラットに腹腔内投与した。
・尿サンプルはＡＡＰＨ投与後より解剖時まで、代謝ケージを用いて採取した。採取した尿については不純物を濾過した後、分析に供するまで−８０℃下に保存した。
・解剖については、ＡＡＰＨ投与終了後より１２時間の絶食を行い、ペントバルビタール系麻酔薬麻酔下において腹大動脈から採血した。血液は遠心分離（４℃、３０００ｒｐｍ、２０分）して血清を採取し、分析に供するまで−８０℃下にて凍結保存した。次に肉眼的観察を行った後、脱血処理を施した後に肝臓を摘出し、重量を測定した。重量測定後は、分析に供するまで−８０℃下にて凍結保存した。
・生化学検査として、血清については総蛋白、アルブミン、総コレステロール、ＨＤＬ−コレステロール、ＬＤＬ−コレステロール、リン脂質、過酸化脂質、ＡＳＴ、ＡＬＴを分析し、尿については８−ＯｈｄＧ（８−Ｈｙｄｒｏｘｙ−ｄｅｏｘｙｇｕａｎｏｓｉｎｅ）を分析した。
・肝臓中の過酸化脂質の測定は、摘出し凍結させた肝臓を解凍後、氷冷下でホモジナイズし、菊川の方法（日本生化学会編 基礎生化学実験法 第５巻 脂質・糖質・複合糖質 東京化学同人）に基づき、チオバルビツール酸（ＴＢＡ）試験より測定した。なお、結果については各試料中のタンパク質あたりのＴＢＡＲＳ（ｎｍｏｌ／ｍｇ ｐｒｏｔｅｉｎ）（チオバルビツール酸反応物：ｔｈｉｏｂａｒｂｉｔｕｒｉｃ ａｃｉｄ ｒｅａｃｔｉｖｅ ｓｕｂｓｔａｎｃｅｓ）として算出した。
・統計処理として、試験結果は平均値±標準誤差で表し、有意差検定はＳｔｕｄｅｎｔ’ｓ−ｔ ｔｅｓｔを用いた。
結果
（Ａ）一般状態および体重推移
一般状態においては、全例において異常は認められなかった。ＡＡＰＨ投与前７日間の体重推移では、Ｃｏｎｔｒｏｌ群、１ｍｇ／ｋｇ群およぴ３０ｍｇ／ｋｇ群のいずれの群においても顕著な差は認められなかった。ＡＡＰＨ投与後の状態観察では、投与後、各群において被毛が逆立つ特有の反応が観察された。サツマイモ茎葉抽出物投与群に関しては、その状態からの回復がＣｏｎｔｒｏｌ群に比較して早期であった。
（Ｂ）摂餌量
試験期間中の摂餌量においては、１ｍｇ／ｋｇ群で１日目にＣｏｎｔｒｏｌ群に対して有意に増加したが、正常範囲の摂餌量であること、翌日より各群間に顕著な差が認められなかったことから、一過性の症状と思われた。
（Ｃ）肝臓重量
肉眼的観察においては、Ｃｏｎｔｒｏｌ群で暗黄赤褐色を呈し、軽度に腫大していたのに対してサツマイモ茎抽出物群については正常に近い赤褐色の色調であった。特に、１ｍｇ／ｋｇ群では３０ｍｇ／ｋｇ群よりも、より正常に近い状態を示した。触診では、Ｃｏｎｔｒｏｌ群では柔らかく各葉の先端部位が鈍角であるのに対して、サツマイモ茎葉抽出物投与群の肝臓は弾力性に富み、各葉の先端部位は鋭角であった。肝臓重量はＣｏｎｔｒｏｌ群４．３８３±０．２０９ｇに対して、１ｍｇ／ｋｇ群では３．９１１±０．２４９ｇ、３０ｍｇ／ｋｇ群では４．０３３±０．３１６ｇとサツマイモ茎葉抽出物投与群で低い値を示した。
（Ｄ）血清およぴ尿中生化学検査
・血清総蛋白：Ｃｏｎｔｒｏｌ群４．８８±０．１０ｇ／ｍＬに対し、１ｍｇ／ｋｇ群５．０４±０．０５ｇ／ｍＬ、３０ｍｇ／ｋｇ群５．００±０．０５ｇ／ｍＬと高い値を示した。
・血清アルブミン：Ｃｏｎｔｒｏｌ群２．７０±０．０５ｇ／ｍＬに対し、１ｍｇ／ｋｇ群２．９０±０．０７ｇ／ｍＬ、３０ｍｇ／ｋｇ群２．７４±０．０５ｇ／ｍＬと１ｍｇ／ｋｇ群でやや高い値を示した。
・血清総コレステロール：Ｃｏｎｔｒｏｌ群４０．１８±５．５５ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群５５．７４±２．９３ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群４８．４０±６．４１ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群でやや高い値を示した。
・血清ＨＤＬ−コレステロール：Ｃｏｎｔｒｏｌ群１６．２０±１．４６ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群２２．２０±０．５８ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群１８．２０±２．２９ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群でやや高く、特に１ｍｇ／ｋｇ群で高い値を示した。
・血清ＬＤＬ−コレステロール：Ｃｏｎｔｒｏｌ群２．８８±１．２９ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群５．６０±１．２９ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群４．００±１．３０ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群でやや高く、特に１ｍｇ／ｋｇ群で高い値を示した。
・血清リン脂質：Ｃｏｎｔｒｏｌ群７１．９８±４．９０ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群８４．０４±４．１６ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群８１．４０±４．６８ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群でやや高く、特に１ｍｇ／ｋｇ群で高い値を示した。
・血清過酸化脂質：Ｃｏｎｔｒｏｌ群０．８４±０．１２ｎｍｏｌ／ｍＬに対し、１ｍｇ／ｋｇ群０．６８±０．０７ｎｍｏｌ／ｍＬ、３０ｍｇ／ｋｇ群０．５８±０．０２ｎｍｏｌ／ｍＬとサツマイモ茎葉抽出物投与群で低く、特に３０ｍｇ／ｋｇ群で低い値を示した。
・血清ＡＳＴ：Ｃｏｎｔｒｏｌ群２０４．６４±５５．８５ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群９９．７２±２３．９３ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群１４８．４０±４１．２４ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群で低く、特に１ｍｇ／ｋｇ群で低い値を示した。
・血清ＡＬＴ：Ｃｏｎｔｒｏｌ群７０．３６±１７．５６ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群３９．５２±５．８６ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群４９．００±１０．５８ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群で低い値を示した。
・尿中８−ＯＨｄＧ：Ｃｏｎｔｒｏｌ群４１．５６±４．９０ｍｇ／ｍＬに対し、１ｍｇ／ｋｇ群２１．６０±２．７５ｍｇ／ｍＬ、３０ｍｇ／ｋｇ群１９．８８±１．８５ｍｇ／ｍＬとサツマイモ茎葉抽出物投与群で有意（ｐ＜０．０５）に低い値を示した。結果を図３（ａ）に示す。
・肝臓ＴＢＡＲＳ：Ｃｏｎｔｒｏｌ群０．４８６±０．０３５ｎｍｏｌ／ｍｇ ｐｒｏｔｅｉｎに対し、１ｍｇ／ｋｇ群０．２９６±０．０２５ｎｍｏｌ／ｍｇ ｐｒｏｔｅｉｎ、３０ｍｇ／ｋｇ群０．２８６±０．０２０ｎｍｏｌ／ｍｇ ｐｒｏｔｅｉｎとサツマイモ茎葉抽出物投与群で有意（ｐ＜０．０１）に低い値を示した。結果を図３（ｂ）に示す。
抗酸化作用を検討する指標として、ＡＡＰＨ投与後より解剖時までの１２時間採取した尿申の８−ＯＨｄＧ、肝臓中ＴＢＡＲＳについて測定した結果、尿中の８−ＯＨｄＧならび肝臓中ＴＢＡＲＳは、Ｃｏｎｔｒｏｌ群に比較して、サツマイモ茎葉抽出物投与群が有意に低い値を示した。解剖時の肉眼的観察では、特に１ｍｇ／ｋｇ群でその状態が良好であり、肝臓重量についても低い値を示した。さらに、血清生化学検査値では、同様にサツマイモ茎葉抽出物投与群で良好であり、肉眼的観察同様に３０ｍｇ／ｋｇ群よりも１ｍｇ／ｋｇ群でその傾向を示した。３０ｍｇ／ｋｇ群では、血清過酸化脂質ならびに尿申８−０ＨｄＧが１ｍｇ／ｋｇ群よりも低い値であった。
以上の結果から、サヅマイモ茎葉抽出物は、ラジカル開始剤ＡＡＰＨを腹腔内に投与することによる生体内脂質過酸化を誘発させたモデル動物において、高濃度摂取では血清過酸化脂質、肝臓中ＴＢＡＲＳおよぴ尿中８−ＯＨｄＧ等の過酸化物の産生を有意に抑制する抗酸化作用を示し、また、低濃度摂取では高濃度よりも緩やかな抗酸化作用を示すとともに、肝臓の障害を軽減し肝臓を保護する作用をもつ素材であることが確認された。
（上記結果に関する考察）
上記実験結果は実に驚くべきものであった。つまりここで用いたサツマイモ茎葉抽出物中のポリフェノール類はカテキン換算の含量として約３０％であり、体重６０ｋｇの人に換算すると０．３×１ｍｇ／ｋｇ×６０ｋｇ＝１８ｍｇとなる。ポリフェノール成分として１日わずか２０ｍｇ程度の摂取量で機能性を発揮すると予想される。一方、最近脚光を浴びている茶カテキンを比較するとその機能性を発揮する量として人で５００ｍｇという値が公表されている（バイオサイエンスとインダストリー Ｖｏｌ．６１ Ｎｏ．１１ ２００３）。茶カテキンの機能性としては体脂肪低減作用であり、本発明のサツマイモ茎葉抽出物とは機能性が異なるが、ポリフェノールの有効濃度が茶カテキンより１桁低く、高活性であることはわれわれの予想を越えるものであった。また、２００４年度の日本農芸化学会で九州沖縄農業研究センターのグループから紫サツマイモの塊根から調製したアントシアニンを含むサツマイモジュースの四塩化炭素投与による肝機能障害軽減効果に関し報告があった。発表の紫サツマイモのジュースには１２０ｍｌで１２．６ｇの紫サツマイモ成分が含まれており、投与量としてはアントシアニン換算で１日５０ｍｇ／ｋｇとなるようであったが、本発明のサツマイモ由来茎葉抽出物の機能性効果はそれと比較して十分に高いと考えられる（２００４年度日本農芸化学会 大会要旨集 ３Ａ１７ｐ１０）。
実施例１０ チロシナーゼ阻害活性の確認
実施例４で得たサツマイモ茎葉抽出物を用いてチロシナーゼ阻害活性を測定した。その測定方法を下記に示す。
（ａ）反応試薬
・チロシン溶液（０．５ｍｇ／ｍＬ）：チロシン２５ｍｇを蒸留水にて５０ｍＬにメスアップし、測定に使用した。
・チロシナーゼ溶液（２５００Ｕ／ｍｇ）：マッシュルーム由来のチロシナーゼ（２５００Ｕ／ｍｇ）６ｍｇを蒸留水にて１００ｍＬにメスアップし、測定に使用した。
・１／１５Ｍリン酸緩衝液（ｐＨ６．８）：リン酸二水素カリウム０．９０７２ｇ蒸留水にて１００ｍＬに、リン酸水素ナトリウム２．３８７６ｇを蒸留水にて１００ｍＬにメスアップした。次に、各々等量を混合した後、ｐＨが６．８であることを確認し測定に使用した。
・５０ｖ／ｖ％エタノール溶液：エタノールおよび蒸留水を等量混合し測定に使用した。
（ｂ）試料対象物の調製
実施例４で得たサツマイモ茎葉抽出物１０ｍｇを５０ｖ／ｖ％エタノール溶液１０ｍＬに溶解し、原液とした。次にその原液を用いて、１／１５Ｍリン酸緩衝液（ｐＨ６．８）にて０．００５ｍｇ、０．０１ｍｇ、０．０５ｍｇ、０．１ｍｇ、０．５ｍｇの量になるよう希釈し、反応に使用した。
（ｃ）チロシナーゼ活性測定
下記の反応系を調製後、３７℃で１時間インキュベートし、４７５ｎｍの吸光度を測定した。対照（Ａｂ）はチロシン溶液（０．５ｍＬ）、リン酸緩衝液（４．０ｍＬ）、チロシナーゼ溶液（０．５ｍＬ）を加え、５．０ｍＬとする。一方、検体（Ａｔ）はチロシン溶液（０．５ｍＬ）、リン酸緩衝液（２．０ｍＬ）、チロシナーゼ溶液（０．５ｍＬ）、各試験溶液（２．０ｍＬ）を加え５ｍＬとする。
（ｄ）チロシナーゼ活性抑制率の算出は下記の計算式で求めた。
抑制率＝（Ａｂ−Ａｔ）／Ａｂ×１００
また、試験対象物のチロシナーゼ５０％抑制濃度（ＩＣ_５０）を算出した。
サツマイモ茎葉抽出物のチロシナーゼ阻害活性を美白作用が知られるコウジ酸やアスコルビン酸と比較して測定した。その結果を表５に示した。

表５からサツマイモ茎葉抽出物のチロシナーゼ活性抑制作用について、ｉｎ ｖｉｔｒｏによるチロシナーゼ活性測定を行ったところ、０．０５ｍｇでチロシナーゼ活性抑制率が６６．４０％とコウジ酸、アスコルビン酸と比較して高い活性を示した。また抑制率の結果からは、ＩＣ_５０は０．０３７ｍｇと推定された。
実施例１１ 糖吸収抑制効果の確認
実施例４で得たサツマイモ茎葉抽出物を用いて動物実験で糖の吸収抑制作用について、グルコース投与による糖負荷試験を行った。試験の材料と方法を下記に示す。
（ａ）供試動物
種：ラット、系統：ＳＤ、性別：オス、入荷時週齢：４週齢
（ｂ）試験群の設定
コントロール群：５匹、３０ｍｇ／ｋｇ投与群：５匹
（ｃ）試験項目および方法
・体重については、予備飼育期間中のみ毎日午前１０から１１時の間に測定した。なお、糖負荷試験は前日の体重を考慮して、４群に群分けを行った。
・サツマイモ茎葉抽出物は蒸留水にて各濃度に調製し、胃ゾンデを用いて経口投与した。
・糖負荷試験は、試験前日より１８時間絶食後、グルコースを２ｇ／ｋｇ経口投与し、投与前（０分）、投与後３０、６０、９０、１２０分に眼窩静脈叢より採血し、血糖測定機を用いて測定した。なお、サツマイモ茎葉抽出物はグルコース負荷３０分前に投与した。また、各測定値をもとに１２０分間のΔ血糖面積値（ＡＵＣ：ｍｇ／ｄＬ・ｈｒ）を下記の計算式より算出した。
計算式
ＡＵＣ（０−Ｔ４）＝Ｃ１Ｔ１／２＋（Ｃ１＋Ｃ２）（Ｔ２−Ｔ１）／２＋（Ｃ２＋Ｃ３）（Ｔ３−Ｔ２）／２＋（Ｃ３＋Ｃ４）（Ｔ４−Ｔ３）／２
Ｃ１：０分から３０分時の血糖上昇値
Ｃ２：０分から６０分時の血糖上昇値
Ｃ３：０分から９０分時の血糖上昇値
Ｃ４：０分から１２０分時の血糖上昇値
Ｔ：経過時間（ｈｒ） Ｔ１：０．５ｈｒ、Ｔ２：１．０ｈｒ、Ｔ３：１．５ｈｒ、Ｔ４：２．０ｈｒ
・統計処理として、試験結果は平均値±標準誤差で表し、有意差検定はＳｔｕｄｅｎｔ’ｓ−ｔ ｔｅｓｔを用い、」対照群に対しｐ＜０．０５で有意とした。
サツマイモ茎葉抽出物の糖負荷試験の結果について表６に示した。

表６の結果を、グラフとして図４に示す。グルコース投与３０分後において、すべての群で血糖値が最も上昇したが、サツマイモ茎葉抽出物投与群は対照群と比較して有意な上昇抑制が認められた。６０分後においても、対照群に対して低値を示し、有意差も認められた。グルコース負荷１２０分間のΔ血糖面積値（ＡＵＣ：ｍｇ／ｄＬ・ｈｒ）では、対照群が最も高い値を示し、サツマイモ茎葉抽出物投与群は有意に低値を示した。以上により、サツマイモ茎葉抽出物の糖吸収抑制作用が確認された。
さらに、上記と同様の条件で、血糖上昇抑制効果について、グアバ葉抽出物との比較試験を行った。試験群は、サツマイモ茎葉抽出物３０ｍｇ／ｋｇ群、１００ｍｇ／ｋｇ群、グアバ葉抽出物１００ｍｇ／ｋｇ群および対照群とし、ラット各５匹で行った。各試験対象物は生理食塩水にて調製し、対照群は生理食塩水のみの投与とした。
上記と同様、試験対象物を投与後、グルコース２ｇ／ｋｇ経口投与して、上記と同様の採血スケジュールで採血を行い、血糖値を測定した。各測定値をもとに経時的な血糖濃度のグラフを図５に示した。
グルコース投与３０分後において、全ての群で血糖値が最も上昇したが、サツマイモ茎葉抽出物群およびグアバ葉抽出物群は、対照群と比較して血糖値上昇の直線の傾きが緩やかであり、各群とも糖吸収を抑制していることが推認された。サツマイモ茎葉抽出物３０ｍｇ／ｋｇ群は、グアバ葉抽出物１００ｍｇ／ｋｇ群と同程度の血糖値の推移を示し、サツマイモ茎葉抽出物の３０ｍｇ／ｋｇ群と１００ｍｇ／ｋｇ群とでは、用量依存的に血糖値上昇抑制を示した。以上より、サツマイモ茎葉抽出物は、グアバ葉抽出物と比較して、より強力な血糖上昇抑制作用を有していることが示唆された。
実施例１２ 脂肪吸収抑制作用の確認
実施例４で得たサツマイモ茎葉抽出物を用いて動物実験で脂肪吸収抑制作用について、大豆油投与による脂肪負荷試験を行った。試験の材料と方法を下記に示す。
（ａ）供試動物
種：ラット、系統：ＳＤ、性別：オス、入荷時週齢：４週齢
（ｂ）試験群の設定
コントロール群：５匹、３０ｍｇ／ｋｇ投与群：５匹
（ｃ）試験項目および方法
・体重については、予備飼育期間中のみ毎日午前１０から１１時の間に測定した。なお、脂肪負荷試験は前日の体重を考慮して、４群に群分けを行った。
・サツマイモ茎葉抽出物は蒸留水にて各濃度に調整し、胃ゾンデを用いて経口投与した。
・脂肪負荷試験は、試験前日より１８時間絶食後、植物（大豆）油を２ｇ／ｋｇ経口投与し、投与前（０分）、投与後３０、６０、１２０、１８０、２４０、３００分に眼窩静脈叢より採血した。その血液は遠心分離（４℃、３０００ｒｐｍ、２０分）して血漿を採取し、市販キットを用いてトリグリセライド濃度を測定した。なお、サツマイモ茎葉抽出物は植物油投与直前に投与した。また、各測定値をもとに３００分間のΔ中性脂肪面積値（ＡＵＣ：ｍｇ／ｄＬ・ｈｒ）を下記の計算式より算出した。
計算式
ＡＵＣ（０−Ｔ４）＝Ｃ１Ｔ１／２＋（Ｃ１＋Ｃ２）（Ｔ２−Ｔ１）／２＋（Ｃ２＋Ｃ３）（Ｔ３−Ｔ２）／２＋（Ｃ３＋Ｃ４）（Ｔ４−Ｔ３）／２＋（Ｃ４＋Ｃ５）（Ｔ５−Ｔ４）／２＋（Ｃ５＋Ｃ６）（Ｔ６−Ｔ５）／２
Ｃ１：０分から３０分時の中性脂肪上昇値
Ｃ２：０分から６０分時の中性脂肪上昇値
Ｃ３：０分から１２０分時の中性脂肪上昇値
Ｃ４：０分から１８０分時の中性脂肪上昇値
Ｃ５：０分から２４０分時の中性脂肪上昇値
Ｃ６：０分から３００分時の中性脂肪上昇値
Ｔ：経過時間（ｈｒ） Ｔ１：０．５ｈｒ、Ｔ２：１．０ｈｒ、Ｔ３：２ｈｒ、Ｔ４：３ｈｒ、Ｔ５：４ｈｒ、Ｔ６：５ｈｒ
・統計処理として、試験結果は平均値±標準誤差で表し、有意差検定はＳｔｕｄｅｎｔ’ｓ−ｔ ｔｅｓｔを用い、」対照群に対しｐ＜０．０５で有意とした。
サツマイモ茎葉抽出物の脂肪負荷試験の結果について表７に示した。

表７の結果を図６に示す。植物油投与６０分において、サツマイモ茎葉抽出物投与群は血中中性脂肪濃度の上昇傾向は認められるものの、対照群に対し有意に低値を示した。１２０分後では、対照群の６０分時とほぼ同値であったが、サツマイモ茎葉抽出物投与群は低値を示しているものの、サツマイモ茎葉抽出物投与群はこの時点が最も上昇していることから、脂肪吸収の遅延作用があるものと推察される。
植物油投与１８０分、２４０分後では、サツマイモ茎葉抽出物投与群は対照群と比較して低い値を示し、１８０分時では有意差も認められた。３００分後においては、群間差は認められなかった。以上からサツマイモ茎葉抽出物の脂肪吸収抑制作用が確認された他、吸収遅延作用も有する可能性が考えられる。
さらに上記と同様の条件で、脂肪吸収抑制作用について、緑茶抽出物（ポリフェノール含量３０％）との比較試験を行った。試験群は、サツマイモ茎葉抽出物３０ｍｇ／ｋｇ群、１００ｍｇ／ｋｇ群、緑茶抽出物３０ｍｇ／ｋｇ群および対照群とし、ラット各５匹で行った。各試験対象物は生理食塩水にて調製し、対照群は生理食塩水のみの投与とした。上記と同様、試験対象物を投与後、食後に植物（大豆）油を２ｍｇ／ｋｇ経口投与し、上記と同様の採血スケジュールで採血を行い、トリグリセ

ｍｇ／ｄＬ・ｈｒ）を上記のとおり計算し、図７に示した。
サツマイモ茎葉抽出物投与群および緑茶抽出物（ポリフェノール含量３０％）投与群はいずれも対照群と比較して、大豆油の摂取により増加する血液中の中性脂肪の量を有意に低下させた。サツマイモ茎葉抽出物と緑茶抽出物の各３０ｍｇ／ｋｇ投与群とを比較すると、サツマイモ茎葉抽出物のほうが、血液中の中性脂肪低下作用が大きいことが分かる。また、サツマイモ茎葉抽出物投与群では、用量依存的に中性脂肪の量を低下させた。以上より、サツマイモ茎葉抽出物は、緑茶抽出物と比較しても、より強力に中性脂肪吸収抑制作用を発揮していることが示唆された。
実施例１３ サツマイモ茎葉抽出物の毒性試験
実施例４で得たサツマイモ茎葉抽出物の単回投与による経口毒性を検討するため、０ｍｇ／ｋｇ（対照群）および２０００ｍｇ／ｋｇの用量で、各用量当たりＳＤ系ラット雌雄各５匹に１回投与し、１４日間観察した。投与液は所定量のサツマイモ茎葉抽出物を秤量し、媒体である２ｖ／ｖ％Ｔｗｅｅｎ８０水溶液に懸濁させ、投与液とした。投与液は投与当日に一回調製した。観察・測定項目として、一般状態の観察（投与前、投与後３０分、１、３、５時間、その後は１日１回、１４日間観察）、体重測定（投与直前、第２，４，８，１５日に電子上皿天秤を用いて測定）、病理学的検査（第１５日に全例をチオペンタールナトリウムの腹腔内投与による麻酔下で腹大動脈を切断・放血し、安楽死させた後剖検）を行った。いずれの群でも死亡例は発現せず、観察期間中、何ら毒性症状も発現しなかった。また、剖検でもなんら異常所見は得られなかった。
実施例１４ サツマイモ葉抽出物を含有する飲料水（熱水抽出物）の作製
焙煎工程を加えることによって、サツマイモ茎葉抽出物の抗酸化性を保持した範囲でサツマイモ茎葉抽出物の味を整えることができる。焙煎する温度や時間を調節することにより、焙煎の程度を調節することが可能である。
サツマイモ葉（乾燥物）を裁断機にてカットし、鍋にて中程度（２分３０秒）に焙煎後、熱水（８０℃）に２０分浸漬し、サツマイモ葉抽出物を含有する飲料水を作成した。シロユタカは葉が大きく、さらに乾燥重量も大きいことから、焙煎等の工程においても扱いやすかった。焙煎工程を経ることによって、焙煎しない場合と比較して、飲料水（サツマイモ茎葉抽出物）に香ばしい香りと味を付与することができた。これはサツマイモ葉に含まれるクロロゲン酸の分解産物であるキナ酸が生じたことも、その一因であると考えられる。また、抽出する水の温度によっても微妙に味や香りを変化させることができる。焙煎したサツマイモ茎葉は本発明の抽出原料として使用することも可能であるが、例えばティーパックに焙煎したサツマイモ茎葉を４グラムずつ包装し、およそ２リットルのお湯に浸漬することで手軽に飲料水（サツマイモ茎葉抽出物）を得ることができ、サツマイモ茎葉抽出物の様々な優れた効果を発揮することのできる、香り、味とも良好な飲料水を製造することができる。
実施例１５ サツマイモ茎葉抽出物の変異原性試験
（１）エームス試験
医薬品遺伝毒性試験ガイドラインに準拠した「エームス試験」により試験管内での変異原性の効果判定を行った。検定菌として，Ｓａｌｍｏｎｅｌｌａ ｔｙｐｈｉｍｕｒｉｕｍ（ＴＡ１００，ＴＡ９８，ＴＡ１５３５，ＴＡ１５３７）およびＥｓｃｈｅｒｉｃｈｉａ ｃｏｌｉ（ＷＰ２ｕｖｒＡ／ｐＫＭ１０１）の５菌株を用いた。実施例４で得たサツマイモ茎葉抽出物（被験検体）５０００μｇ／プレートを最高用量とし、Ｓ９ｍｉｘ添加、無添加群、各６段階（１．２２〜５００）にて用量反応性試験を行ったが、菌の生育阻害は見られなかったため、本試験でも５０００μｇ／プレートを最高用量として５用量を設定して実施し、各濃度での復帰突然変異コロニー数を測定した。その結果、Ａｍｅｓ試験の判定法に準じ、いずれの検定菌においてもＳ９ｍｉｘの有無にかかわらず変異原性は陰性と判断された。
（２）小核試験
医薬品遺伝毒性試験ガイドラインに準拠した「げっ歯類を用いた小核試験」により、サツマイモ茎葉抽出物の生体内での変異原性の効果判定を行った。実施例４で得たサツマイモ茎葉抽出物（被験検体）５００、１０００および２０００ｍｇ／ｋｇを、雄性ラット（７週令、５匹／群）に各用量３例を用いて２回強制経口投与（２４時間間隔）した結果、いずれの群においても死亡は認められず、一般状態にも変化はなかった。したがって、本試験では被験検体については同じ濃度とし、陽性対象にシクロホスファミド１０ｍｇ／ｋｇ、陰性対象に生理食塩水を加えて実施することとした。最終投与２４時間後、被験動物の大腿骨より骨髄細胞を採取して組織標本を作製した。全赤血球中の小核を持つ赤血球の割合を定法にて測定し、統計処理を施した結果、被験検体に関して小核の出現頻度は統計学的に有為でなく変異原性は陰性と判断された。
以上より、いずれの試験においても、サツマイモ茎葉抽出物の変異原性は陰性という結果であり、サツマイモ茎葉抽出物の摂取によって突然変異を起こす可能性は低く、極めて安全性が高いことが示唆された。
実施例１６ サツマイモ茎葉抽出物の脱臭効果試験
ヒトやペットの口臭、体臭、便臭等の原因物質に対する消臭効果を検討した。
（１）３００ｍｌのコニカルビーカーに１００ｍｌ純水にアンモニア、トリメチルアミン、メルカプタンを添加し、アルミホイルで蓋をした。
（２）ヘッドスペース部を各成分の濃度を検知管にて測定し、実施例４で得たサツマイモ茎葉抽出物を１ｇ入れ攪拌し、ヘッドスペース部の各成分の濃度を検知管にて測定した。
測定結果を図８に示した。アンモニア、トリメチルアミンはサツマイモ茎葉抽出物を添加した直後に臭気は感じられず、濃度も検出限界以下となった。また、メチルメルカプタンについては、サツマイモ茎葉抽出物添加直後に部分的に分解され、減臭効果が認められた。以上より、サツマイモ茎葉抽出物は異なる種類の臭気に対しても脱臭効果を発揮することが示唆された。サツマイモ茎葉抽出物は本発明の安全性試験によって、生体に対して極めて安全性が高いことが確認されていることから、ヒトやペットの口臭、体臭、便臭に対する消臭、飲食品の消臭等にも使用することができ、脱臭効果を有する物質の中でも、極めて幅広い応用範囲で使用可能な物質であるといえる。
実施例１７ ラット白色脂肪細胞を用いた脂肪細胞分化および肥大化抑制試験
脂肪細胞の増加抑制効果を調べるため、ｉｎ ｖｉｔｒｏにおけるラット腸間膜由来白色脂肪細胞の分化および肥大化抑制試験を行った。
ラット白色脂肪細胞の脂肪細胞分化および肥大化抑制の観察
ラット白色脂肪細胞キット（（株）セルガレージ）の脂肪細胞を使用し、操作は全て通常の方法に従い行った。まず、脂肪細胞を増殖用培地中で５％ＣＯ_２下２４時間インキュベーションを行った。脂肪細胞が２×１０^５ｃｅｌｌｓ／ｗｅｌｌになるように２４ｗｅｌｌプレートに播種し、２４時間インキュベーションした後、分化誘導培地に交換し、５％ＣＯ_２下４８時間インキュベーションした。さらに脂肪細胞維持培地に交換した後、各試験対象物として、実施例４で得たサツマイモ葉抽出物１００μｇ／ｍＬ、緑茶抽出物（９０％カテキン）１００μｇ／ｍＬを培地中の脂肪細胞に添加し、何も添加しないものをコントロールとして、５％ＣＯ_２下インキュベーションをし、２４ｈごとに細胞の状態を観察した。
各群の脂肪細胞の２４時間後、７２時間後、９６時間後における状態を図９に示した。その結果、サツマイモ茎葉抽出物および緑茶抽出物は両者ともコントロールと比較して、全ての時間にわたり、顕著に脂肪細胞の脂肪滴の蓄積および脂肪細胞の肥大化を抑制した。サツマイモ茎葉抽出物と緑茶抽出物とを比較すると、２４時間後には緑茶抽出物のほうが脂肪滴の蓄積はやや少ないものの、４８時間後（データは示さない）および７２時間後には両者同等となり、９６時間後は両者同等か、もしくはわずかにサツマイモ茎葉抽出物のほうが脂肪細胞の肥大化を抑制した。以上より、サツマイモ茎葉抽出物は、緑茶エキスと比較しても、ほぼ同等か、それ以上の脂肪細胞の分化および肥大化抑制効果効果を有することが分かった。従って、本発明のサツマイモ茎葉抽出物は、脂肪細胞の分化および肥大化が原因となって生じる肥満の予防・治療剤として利用できる可能性が示唆された。
実施例１８ マウス強制水泳法による抗うつ作用および抗疲労作用の検討
マウス強制水泳法により、サツマイモ茎葉抽出物の抗うつ作用および抗疲労作用の検討を行った。
マウス（ＢＡＬＢ／ｃ系統・雄・７週齢）は、本試験開始前日まで７日間予備飼育を行い馴化した。予備飼育終了２日前に供試動物を５分間強制遊泳させ、試験対象物投与前の遊泳状態が均一になるようにスクリーニングを行い、予備飼育最終日の体重も考慮して、供試動物６匹ずつ群分けを行い、本試験を開始した。試験群は、実施例４で得たサツマイモ葉抽出物 ３０ｍｇ／ｋｇ群、３００ｍｇ／ｋｇ群、セントジョーンズワート３００ｍｇ／ｋｇおよび対象群とした。各試験対象物は生理食塩水にて調製し、胃ゾンデを用いて強制経口投与（１０ｍＬ／ｋｇ）した。なお、コントロール群については、生理食塩水を同様に強制経口投与（１０ｍＬ／ｋｇ）した。試験対象物を投与してから、１時間後に１０Ｌの温水（３７℃）を満たしたアクリル製水槽（３５０×４００×１８０ｍｍ）中で遊泳させ、遊泳状態を観察した。判定は、下記基準に準拠して持続時間を測定した。
判定基準
ＥＤＢ（ｅｓｃａｐｅ ｄｉｒｅｃｔｅｄ ｂｅｈａｖｉｏｒ）： 水槽より跳び出ようとする行動、あるいは潜水して出口を捜し求めるような行動
ＩＭＯ（ｉｍｍｏｂｉｌｉｔｙ）： ほとんどの動きを停止し、単に浮遊しているだけの状態
各群のＥＤＢおよびＩＭＯ時間の平均値を図１０に示した。サツマイモ茎葉抽出物およびセントジョーンズワート抽出物投与群は、コントロール群に対してＥＤＢの有意な延長とＩＭＯの有意な短縮が認められた。また、サツマイモ茎葉抽出物投与群については濃度依存的な効果を示し、サツマイモ茎葉抽出物３００ｍｇ／ｋｇ群はセントジョーンズワート３００ｍｇ／ｋｇ群とほぼ同等の効果がみられた。セントジョーンズワートは、気分をリラックスさせ、ストレスに効果のあるハーブとして広く知られ、ドイツでは、軽〜中等度のうつ症状に対して、実際に抗うつ薬として使用されている。サツマイモ茎葉抽出物群はセントジョーンズワート群と同様に、強制的な運動負荷や精神的ストレスに対して有効であったことから、サツマイモ茎葉抽出物は、単回経口投与でも十分に、精神的および肉体的なストレス、疲労に対して有効であり、セントジョーンズワートとほぼ同等の、抗うつ作用、抗ストレス作用、リラックス作用を有することが示唆された。
実施例１９ 油脂安定性試験
実施例４で得たサツマイモ茎葉抽出物をビタミンＥフリーの豚脂３ｇに対し、それぞれ２００ｐｐｍ、１０００ｐｐｍとなるように添加し、試料液とした。乾燥空気流量２０Ｌ／ｈｒ、温度１２０℃下、試料液を自動油脂安定性試験装置（ＣＤＭ試験装置）により、油脂の変敗開始時間を求めた。
サツマイモ茎葉抽出物の濃度における変敗時間を図１１に示した。サツマイモ茎葉抽出物は、０ｐｐｍで１．６時間であった変敗時間を、２００ｐｐｍで豚脂の変敗時間を２倍（３．３時間）に延長し、１０００ｐｐｍで３倍（５時間）に延長した。以上より、サツマイモ茎葉抽出物は、豚脂・ラードなどの動物脂質を使用する加工食品（フライドポテトやスナック、カップ麺等）をはじめ、その他様々な油脂類に添加し、油脂の劣化防止に応用できる可能性が示唆された。
実施例２０ サツマイモ茎葉抽出物を用いた製剤の作製
本発明のサツマイモ茎葉抽出物を用いて、下記の３種類の製剤を作製した。
（１）顆粒剤の作製
下記の表８のとおり、サツマイモ茎葉抽出物を終濃度５％となるように各種賦形剤と混合し、合計２ｋｇの原料を適量の水を加えて練合の上、噴霧乾燥造粒機を用いて顆粒剤を作製した。製造した顆粒剤は２グラムごとにアルミ包装した。本品は携帯に便利であり、水溶性も良好であるため、用時１００ｍＬ程度のお湯あるいは水に溶解することで美味しく飲料化することができた。本品は１包当たりサツマイモ茎葉抽出物１００ｍｇを含有する。

（２）錠剤の作製
下記の表９のとおり、サツマイモ茎葉抽出物１ｋｇを終濃度２０％となるように各種賦形剤と混合し、合計５ｋｇの原料をもとに適量の水を加えて練合の上、打圧式の錠剤製造機を用いて１錠２５０ｍｇの錠剤を作成した。本品は１錠当たりサツマイモ茎葉抽出物５０ｍｇを含有する。

（３）グミの作製
下記の表１０のとおり、サツマイモ茎葉抽出物１０ｇをグミ基剤１ｋｇと加熱下混合し、糖度が８０％程度になるまで煮詰める。クエン酸液ならびに果汁及び香料を加え、熱いうちに一粒５ｇに成型した（サツマイモ茎葉抽出物終濃度０．１％）。本品は１粒当たりサツマイモ茎葉抽出物５ｍｇを含有する。

サツマイモ茎葉抽出物は、各製剤中への配合率を目的に応じて適宜増減することも可能であり、また、他の機能性素材、飲食品素材や香料と混合することも容易であることから、機能性素材としての取り扱い性に優れ、極めて応用範囲が広いことが分かった。また、飲食品の素材としても同様に幅広く使用可能であるといえる。  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.
Example 1 Examination of extraction conditions of sweet potato stem and leaf extract
In the production of sweet potato stem and leaf extract, it was investigated how the extraction efficiency of polyphenols varied with ethanol concentration. Shiroyutaka was used as a sweet potato variety, and the stems and leaves of 4 months of cultivation were harvested, and those dried on the sun were crushed and used for extraction. The extraction and purification operation was performed according to the following procedure.
(1) As an examination of conditions, 90 g of dried and crushed sweet potato stalks and leaves were used under one extraction condition.
(2) As the setting of extraction conditions, examination was performed under five conditions with different ethanol concentrations (0% (water), 20%, 40%, 60%, 80%).
(3) Extraction is performed by leaving the first 700 ml of the extract at room temperature for 12 hours, followed by filtration, collecting the filtrate, adding 500 ml of the extract to the extraction residue, and performing the extraction for 12 hours. It was. Thereafter, the same operation was performed, extraction was performed three times in total, and the collected extracts were combined.
(4) The extract was concentrated to about 200 ml with a rotary evaporator, and then fractionated with 50 ml of hexane to collect the aqueous layer portion.
(5) Purification was performed using DIAION HP20 sold by Mitsubishi Chemical. A column was prepared by replacing 50 g of DIAION HP20 with water, and the collected aqueous layer portion was passed through the column. Thereafter, the column was washed with about 500 ml of water and the polyphenol fraction was eluted with about 250 ml of 90% ethanol and collected.
(6) The collected polyphenol fraction was measured for the amount of polyphenol and concentrated to dryness, and the weight was measured.
  The collected polyphenol fraction was measured for polyphenol content in terms of catechin using a polyphenol measuring device (PA-20) sold by Toyobo Engineering Co., Ltd.

  As can be seen from Table 1, if the ethanol concentration is 40% or more, 300 mg or more of polyphenols are extracted. As for the ratio of polyphenol weight per dry weight, the maximum ethanol concentration was 60%, which was 23.6%.
  Next, the stability of polyphenols in the extract was examined. Regarding the stability, the polyphenol concentration immediately after extraction was compared with the polyphenol concentration after being left indoors for 12 days, and the rate of decrease in concentration was used as an indicator of stability. The results are shown in Table 2.

  As can be seen from Table 2, it was found that when the ethanol concentration was lowered, the polyphenol concentration after 12 days was lowered. From this, it is considered that an ethanol concentration of at least 40% or more, preferably 60% or more is appropriate for the extract. In addition, when the ethanol concentration is high (80%), it is observed that components such as chlorophyll and oil are extracted, and considering that the yield of polyphenol is slightly reduced, extraction with an ethanol concentration higher than 80% is performed. There seems to be no advantage to do.
Example 2 Examination of purity improvement method of polyphenol
  In functional foods, it is important to increase the purity of functional ingredients at no cost. For example, undesirable components such as astringency may be included in impurities, and relatively undesirable components can be reduced by increasing the purity. Therefore, extraction was carried out separately for the stems and leaves of sweet potato, and after concentration, a method for removing precipitates that occurred with time was studied. The following items were examined as examination conditions.
(A) A stem of sweet potato was separated, a polyphenol fraction was obtained by the method of Example 1 using 60% ethanol, and the amount of polyphenol per dry weight, that is, the purity of the fraction was examined. However, the hexane fraction in Example 1 was omitted.
(B) The leaves of sweet potato were separated, a polyphenol fraction was obtained by the method of Example 1 using 60% ethanol, and the amount of polyphenol per dry weight, that is, the purity of the fraction was examined. However, the hexane fraction in Example 1 was omitted as in (a).
(C) The sweet potato leaf was separated and extracted by the method of Example 1 using 60% ethanol to obtain 200 ml of a concentrated solution. The concentrated solution was allowed to stand for 3 days, and then the precipitate formed in 3 days was removed. The removed product was passed through an HP-20 column and the polyphenol fraction was collected in the same manner as in Example 1. Then, the amount of polyphenol per dry weight of the fraction, that is, the purity was examined. However, the hexane fraction in Example 1 was omitted as in (a).
(D) The sweet potato leaves were separated and extracted by the method of Example 1 using 60% ethanol to obtain 200 ml of concentrated liquid. About 4 times the volume of ethanol was added to the concentrated liquid and left for 3 days. After removing the precipitate produced in 3 days, ethanol was removed again by a rotary evaporator, and then the mixture was passed through an HP-20 column and the polyphenol fraction was collected in the same manner as in Example 1. Then, the amount of polyphenol per dry weight of the fraction, that is, the purity was examined. However, the hexane fraction in Example 1 was omitted as in (a).
  The results are shown in Table 3.

  As can be seen from Table 3, when extracted from leaves, the amount of polyphenol can be extracted about 10 times more efficiently than the stem, and the polyphenol purity calculated as catechin conversion is high. Moreover, after extracting and concentrating by the method of Example 1, it turned out that purity improves by leaving still. In addition, when ethanol was added, the purity was as high as 56.4%. This is considered to be due to the fact that ethanol concentration is low under the standing condition of (c), and therefore it is necessary to consider partial decomposition and disappearance. From the above, it is possible to improve the polyphenol purity (usually 20% to 30%) to about 60% by removing the precipitate after performing the stationary treatment after concentration and waiting for the formation of the precipitate. I understood it.
Example 3 Retrieval of components by liquid chromatography
  The components of the polyphenol fraction (sweet potato foliage extract) extracted and fractionated from sweet potato foliage or leaves by the method of Example 1 using 60% ethanol were searched for by liquid chromatography. Conditions are shown below.
Condition: Column: Shima-pack VP-ODS (manufactured by Shimadzu)
      Column temperature: 40 ° C
      Eluent: Solution A 4.5 mM citrate water: Acetonitrile: Isopropanol
                  100: 10: 3
                B liquid 6 mM citric acid water: acetonitrile: isopropanol
                  100: 47: 3
      Eluent gradient: Time A / B
                    0min 85/15
                    40min 0/100 (linear gradient)
                    50min 0/100
                    60min 85/15 (linear gradient)
  FIG. 1 shows a liquid chromatography chart of the sweet potato stem and leaf extract obtained by the method of Example 1 using 60% ethanol from the sweet potato stem and leaf. From the analysis of the peaks, the extract contains quercetin-3-glucoside, quercetin-3-galactoside, chlorogenic acid and three dicaffeoylquinic acids (3,4-dicaffeoylquinic acid, 3,5-diacid). Caffeoylquinic acid, 4,5-dicaffeoylquinic acid) was found to be contained. FIG. 2 shows a liquid chromatography chart of the sweet potato stem and leaf extract obtained by the method of Example 1 using 60% ethanol from sweet potato leaves. It was found that the extract using only leaves contained a large amount of quercetin-3-glucoside and quercetin-3-galactosid.
Example 4 Production of sweet potato stem and leaf extract using 80% ethanol
  A sweet potato shoot extract was produced by the following method.
(1) Put 2.22 kg of dried potato leaves and leaves into a 20 L extractor, add 13.2 L of 80% ethanol, perform warm extraction (75 ° C.) for 2 hours, and filter with Nutsche to obtain about 10 L of extract. It was.
(2) Further, the same operation is performed three times. An extract 40L was obtained. The extract was concentrated to about 1/7 under reduced pressure.
(3) After adding 8.0 L of hexane and separating the fat-soluble component, the hexane layer was removed.
(4) The solvent was distilled off from the aqueous layer portion under reduced pressure until the solution was about 5 L.
(5) 5 L of water was added to the concentrated solution. Since impurities accumulated in the lower layer of the diluted solution, insoluble matters were removed by decantation.
(6) After passing the supernatant liquid through 3 L of the adsorption resin (HP20), the resin was washed with 4 L of water.
(7) The adsorbate was eluted from the resin with 10 L of 90% ethanol.
(8) The eluate was evaporated to dryness under reduced pressure, and 54.43 g (yield 2.45%) of a powder sample was obtained using a spray dryer.
  The obtained powder sample (sweet potato stem and leaf extract) had a polyphenol content of about 34% in terms of catechin, and the quercetin-3-glucoside content in the polyphenol was 5.6%. Further, it was confirmed by liquid chromatography that quercetin-3-glucoside, quercetin-3-galactoside, chlorogenic acid and dicaffeoylquinic acid were contained in the same manner as in Example 3.
Example 5 Production of sweet potato stem and leaf extract using 60% ethanol
  1.5 kg of dried sweet potato stalks and leaves were crushed, 6.1 L of 60% ethanol was added, extraction was performed for 2 hours or more, and the primary extract was squeezed to recover 3.5 L. The same amount of 60% ethanol as the primary juice was added and left for 12 hours or longer, and then the secondary extract was squeezed to recover 3.34 L. The primary extract and the secondary extract were combined and concentrated under reduced pressure to about 1/3 volume (2.3 L) using a rotary evaporator. The oily component adhering to the wall surface was removed by decantation, and twice the amount of 100% ethanol was added to the resulting aqueous solution and left for 12 hours or longer. The precipitate (which seems to be a polysaccharide or the like) was removed by decantation, and the supernatant was concentrated under reduced pressure to about 1/7 volume (990 ml) with a rotary evaporator. The resulting aqueous solution was passed through a DIAION HP20 (Mitsubishi Chemical) column. After washing with 5 times the column volume of water, it was eluted with 90% ethanol twice the column volume, and the eluate was dried with a spray dryer to obtain a sweet potato shoot extract. The extract yield from the dried foliage was 0.66%, the polyphenol content in the extract was 41.3%, and the quercetin-3-glucoside content in the polyphenol was 3.0%. Further, it was confirmed by liquid chromatography that quercetin-3-glucoside, quercetin-3-galactoside, chlorogenic acid and dicaffeoylquinic acid were contained in the same manner as in Example 3.
Example 6 Comparison of extraction methods
  The quercetin-3-glucoside extract amount was compared for 60% ethanol extraction, hot water extraction, and water extraction.
(1) 60% ethanol extraction
  The dried sweet potato stalks and leaves were extracted with 60% ethanol, concentrated with a rotary evaporator, applied to an HP20 column, the fraction eluted with 90% ethanol was dried, and the amount of quercetin-3-glucoside extracted was measured.
(2) Hot water extraction and ethanol precipitation
  Extract the dried sweet potato stems and leaves with hot water at 90 ° C, add twice the amount of 100% ethanol, remove the resulting precipitate, concentrate on a rotary evaporator, apply to a HP20 column, and dry the fraction eluted with 90% ethanol. After solidification, the amount of quercetin-3-glucoside extracted was measured.
(3) Hot water extraction
  The dried sweet potato stems and leaves were extracted with hot water at 90 ° C., concentrated on a rotary evaporator, applied to an HP20 column, the fraction eluted with 90% ethanol was dried, and the amount of quercetin-3-glucoside extracted was measured.
(4) Water extraction
  Extract the dried sweet potato stems and leaves with water, add twice the amount of 100% ethanol, remove the resulting precipitate, concentrate on a rotary evaporator, apply to an HP20 column, dry the fraction eluted with 90% ethanol, and dry the quercetin The amount of -3-glucoside extracted was measured. The results are shown in Table 4.

  As for the extraction amount of quercetin-3-glucoside, it was found that 60% ethanol was superior. In addition, it was found that hot water extraction or water extraction requires some contrivance when performing column purification because substances that are insoluble in ethanol inhibit purification during the column purification process.
  A large amount of insoluble components in ethanol is extracted by hot water extraction. This substance is considered to be insolubilized during elution with 90% ethanol during the column purification process. Even though the column was washed with water, it strongly bound to the resin during elution with 90% ethanol. , Brown color is not lost. This was expected to affect column regeneration. Subsequently, when a double amount of 100% ethanol was added to the hot water extract or the water extract to obtain an ethanol concentration of 67%, a large amount of hazy and sticky precipitate was deposited. When column purification was performed after filtering the precipitate, pigmentation on the column was not observed. However, the manufacturing method in which a column purification process is added to hot water extraction and water extraction is inferior to 60% ethanol extraction in the amount of quercetin-3-glucoside extraction. Therefore, it is judged that the superiority is low in terms of extraction efficiency compared with 60% ethanol extraction.
Example 7 Comparison of foliage components of various sweet potato varieties
  The polyphenol components contained in the foliage were compared between the sweet potato cultivar Shiroyutaka used in Examples 1 to 6, and the four cultivars Koganesengan, SUKUH, Murasaki Tanegashima and Shimo-imo. Shiroyutaka, Koganesengan, SUKUH, and Tanegashima purple extracted the dried sweet potato foliage with 60% ethanol and filtered the sample for HPLC analysis. For Simian potato, a sample of commercially available tea (tea using leaves and leaves) extracted with 60% ethanol and filtered was subjected to HPLC analysis.
  As a result, there was no significant difference in the types of components detected by chromatography between Shiroyutaka and the other four varieties, and the types of substances contained were considered to be equivalent. Slightly different. Moreover, it turned out that the sweet potato leaf extract using only a white hawk leaf contains many quercetin-3-glucoside compared with the extract of other varieties.
Example 8 Confirmation of antioxidant capacity
  Antioxidant ability was measured using sweet potato stem and leaf extract.
(1) Superoxide scavenging activity
  The superoxide scavenging activity of the sweet potato foliage extract obtained in Example 4 was measured by the electron spin reaction (ESR) method. The result is 3.9 × 10⁴Unit / g (unit defined in J. Biol. Chem., 244, 6049 (1969)), and it was confirmed that sweet potato polyphenol has an antioxidant ability. Pycnogenol (1.6 × 10 6), which is said to have very high antioxidant ability, although it has a high level of antioxidant ability.⁵Compared with the unit / g), it was about a quarter.
(2) DPPH radical scavenging ability
  The DHHP radical scavenging ability of the sweet potato stem and leaf extract obtained in Example 4 and the stem-only extract or leaf-only extract obtained in Example 2 was measured by an electron spin reaction (ESR) method. The sweet potato stem and leaf extract obtained in Example 4 was 653 μmol / g, the stem-only extract obtained in Example 2 was 304 μmol / g, and the leaf-only extract obtained in Example 2 was 1273 μmol / g ( The activity is expressed as an equivalent amount of Trolox μmol per 1 g of sample). In commercial tea powder, it is said to be about 515 μmol / g, and the sweet potato shoot extract showed activity equivalent to or better than tea powder.
(3) Hydroxyl radical scavenging ability
  About the sweet potato stem and leaf extract obtained in Example 4 and the stem-only extract or leaf-only extract obtained in Example 2, the ability to scavenge the hydroxy radicals generated in the hydrogen peroxide-2valent iron ion system Measurement was performed by a spin trapping method using DMPO. The sweet potato stem and leaf extract obtained in Example 4 was 10.8 mmol / g, the stem only extract obtained in Example 2 was 16.8 mmol / g, and the leaf only extract obtained in Example 2 was 14.4 mmol. (Activity is expressed in terms of mmol of mannitol per gram of sample). It is said that the commercially available tea powder is about 9.3 mmol / g, and the sweet potato shoot extract showed an activity equal to or better than that of the tea powder.
Example 9 Liver Protective Action of Sweet Potato Forage Extract
  When the sweet potato stem and leaf extract was ingested in food and beverages, the ingredients were absorbed from the intestinal tract and transferred to the blood, and it was confirmed whether or not free radicals could actually be eliminated in the body. 2,2'-azobisamidinopropane dihydrochloride (AAPH), which is a radical initiator, was administered intraperitoneally to rats administered with a sweet potato foliage extract and untreated rats, and the effects thereof were examined. The test materials and methods are shown below.
(A) Test animal
  Species: Rat, Strain: SD, Gender: Male, Age at arrival: 6 weeks old
(B) Test group setting
  Control group: 5 animals, 1 mg / kg administration group: 5 animals, 30 mg / kg administration group: 5 animals
(C) Test items and methods
  -Measurement of body weight and food consumption: Administration of the sweet potato foliage extract was carried out for 7 days, and the observed body weight and food consumption for the general state were measured every day from 10 am to 11 am. Feed and water were ad libitum.
  -The sweet potato foliage extract obtained in Example 4 was dissolved in distilled water and orally administered using a stomach tube so that the intake of the sweet potato foliage extract was 1 mg / kg or 30 mg / kg per day. For the Control group, 10 mL / kg of physiological saline was administered. In the administration on the 7th day, the sweet potato foliage extract and physiological saline were administered 12 hours before the administration of AAPH.
  -Administration of AAPH is 50 mg / kg B. using physiological saline. W was prepared and administered intraperitoneally to rats.
  -Urine samples were collected using metabolic cages after AAPH administration until dissection. The collected urine was stored at −80 ° C. until it was analyzed after impurities were filtered.
  -For dissection, fasting was performed for 12 hours after the end of AAPH administration, and blood was collected from the abdominal aorta under anesthesia with a pentobarbital anesthetic. Blood was centrifuged (4 ° C., 3000 rpm, 20 minutes) to collect serum, and stored frozen at −80 ° C. until analysis. Next, after macroscopic observation, the blood was removed and the liver was removed and weighed. After the weight measurement, the sample was stored frozen at -80 ° C. until analysis.
  As a biochemical test, serum was analyzed for total protein, albumin, total cholesterol, HDL-cholesterol, LDL-cholesterol, phospholipid, lipid peroxide, AST, ALT, and urine for 8-OhdG (8-Hydroxy- deoxyguanosine) was analyzed.
  ・ Measurement of lipid peroxide in the liver is performed by thawing the extracted and frozen liver and homogenizing it under ice-cooling. The method of Kikukawa (Basic Biochemical Experimental Method, Volume 5 of Lipids, Carbohydrates and Complexes, Japanese Biochemical Society) Carbohydrate, measured by thiobarbituric acid (TBA) test. The results were calculated as TBARS (nmol / mg protein) (thiobarbituric acid reactant: thiobarbituric acid reactive substances) per protein in each sample.
  -As a statistical process, the test result was represented by the average value +/- standard error, and Student's-t test was used for the significant difference test.
result
(A) General condition and weight transition
  In the general state, no abnormality was observed in all cases. In the body weight transition for 7 days before AAPH administration, no significant difference was observed in any of the Control group, 1 mg / kg group and 30 mg / kg group. In the observation of the state after administration of AAPH, a unique reaction was observed in which the hairs turned upside down in each group after administration. Regarding the sweet potato foliage extract administration group, recovery from that state was earlier than that of the Control group.
(B) Food intake
  In the amount of food intake during the test period, the 1 mg / kg group increased significantly compared to the Control group on the first day. However, there was a significant difference between the groups from the following day that the amount was within the normal range. Since it was not observed, it seemed to be a transient symptom.
(C) Liver weight
  Macroscopically, the control group exhibited a dark yellow-reddish brown color and was slightly swollen, whereas the sweet potato stalk extract group had a red-brown color near normal. In particular, the 1 mg / kg group showed a more normal state than the 30 mg / kg group. By palpation, the control group was soft and the tip part of each leaf was obtuse, whereas the liver of the sweet potato shoot extract administration group was highly elastic and the tip part of each leaf was acute. Liver weight is low in the control group 4.383 ± 0.209 g, 3.911 ± 0.249 g in the 1 mg / kg group and 4.033 ± 0.316 g in the 30 mg / kg group, which is lower in the sweet potato foliage extract administration group The value is shown.
(D) Serum and urine biochemistry
  Serum total protein: Control group 4.88 ± 0.10 g / mL, 1 mg / kg group 5.04 ± 0.05 g / mL, 30 mg / kg group 5.00 ± 0.05 g / mL Indicated.
  Serum albumin: 2.70 ± 0.05 g / mL for the control group, 2.90 ± 0.07 g / mL for the 1 mg / kg group, 2.74 ± 0.05 g / mL for the 30 mg / kg group, and the 1 mg / kg group A slightly high value was shown.
  Serum total cholesterol: Extraction of sweet potato foliage with control group 40.18 ± 5.55 mg / mL, 1 mg / kg group 55.74 ± 2.93 mg / mL, 30 mg / kg group 48.40 ± 6.41 mg / mL A slightly higher value was shown in the substance administration group.
  Serum HDL-cholesterol: Control group 16.20 ± 1.46 mg / mL, 1 mg / kg group 22.20 ± 0.58 mg / mL, 30 mg / kg group 18.20 ± 2.29 mg / mL and sweet potato foliage It was slightly higher in the extract administration group, particularly high in the 1 mg / kg group.
  Serum LDL-cholesterol: Control group 2.88 ± 1.29 mg / mL, 1 mg / kg group 5.60 ± 1.29 mg / mL, 30 mg / kg group 4.00 ± 1.30 mg / mL and sweet potato foliage It was slightly higher in the extract administration group, particularly high in the 1 mg / kg group.
  Serum phospholipids: Extraction of sweet potato foliage with control group 71.98 ± 4.90 mg / mL, 1 mg / kg group 84.04 ± 4.16 mg / mL, 30 mg / kg group 81.40 ± 4.68 mg / mL It was slightly higher in the product administration group, particularly high in the 1 mg / kg group.
  Serum lipid peroxide: control group 0.84 ± 0.12 nmol / mL, 1 mg / kg group 0.68 ± 0.07 nmol / mL, 30 mg / kg group 0.58 ± 0.02 nmol / mL and sweet potato foliage It was low in the extract administration group, and particularly low in the 30 mg / kg group.
  Serum AST: 99.72 ± 23.93 mg / mL in the 1 mg / kg group and 148.40 ± 41.24 mg / mL in the 30 mg / kg group for the control group 204.64 ± 55.85 mg / mL It was low in the administration group, particularly low in the 1 mg / kg group.
  Serum ALT: Sweet potato stover extract with control group 70.36 ± 17.56 mg / mL, 1 mg / kg group 39.52 ± 5.86 mg / mL, 30 mg / kg group 49.00 ± 10.58 mg / mL A low value was shown in the administration group.
  ・ Urine 8-OHdG: Control group 41.56 ± 4.90 mg / mL, 1 mg / kg group 21.60 ± 2.75 mg / mL, 30 mg / kg group 19.88 ± 1.85 mg / mL, sweet potato A significantly low value (p <0.05) was shown in the foliage extract administration group. The results are shown in FIG.
  Liver TBARS: Control group 0.486 ± 0.035 nmol / mg protein, 1 mg / kg group 0.296 ± 0.025 nmol / mg protein, 30 mg / kg group 0.286 ± 0.020 nmol / mg protein and sweet potato A significantly low value (p <0.01) was shown in the foliage extract administration group. The results are shown in FIG.
  As an index for studying the antioxidant action, as a result of measurement of 8-OHdG and TBARS in the liver collected for 12 hours from the time of AAPH administration to the time of dissection, urinary 8-OHdG and liver TBARS were measured in the Control group. In comparison, the sweet potato foliage extract administration group showed a significantly lower value. Macroscopic observation during dissection showed that the condition was particularly good in the 1 mg / kg group, and the liver weight was also low. Furthermore, the serum biochemical test values were similarly good in the sweet potato shoot extract administration group, and showed a tendency in the 1 mg / kg group rather than the 30 mg / kg group as in the macroscopic observation. In the 30 mg / kg group, serum lipid peroxide and urinary 8-0HdG were lower than in the 1 mg / kg group.
  From the above results, the sweet potato foliage extract was found to be obtained in a model animal in which in vivo lipid peroxidation was induced by intraperitoneal administration of the radical initiator AAPH. It exhibits an antioxidant effect that significantly suppresses the production of peroxides such as 8-OHdG in human excreta, and also exhibits a milder antioxidant effect than a high concentration when consumed at low concentrations, and reduces liver damage. It was confirmed that the material has a protective effect.
(Discussion on the above results)
  The above experimental results were indeed surprising. In other words, the polyphenols in the sweet potato stem and leaf extract used here are about 30% in terms of catechin, and 0.3 × 1 mg / kg × 60 kg = 18 mg in terms of a person weighing 60 kg. As a polyphenol component, it is expected to exhibit functionality with an intake of only about 20 mg per day. On the other hand, when comparing tea catechins that have recently been in the limelight, a value of 500 mg per person has been published as the amount that demonstrates its functionality (Bioscience and Industry Vol. 61 No. 11 2003). The function of tea catechin is to reduce body fat, which is different from the sweet potato stem and leaf extract of the present invention, but our anticipation is that the effective concentration of polyphenol is an order of magnitude lower than tea catechin and is highly active. It was something that exceeded. In addition, the 2004 Agricultural Chemistry Society of Japan reported on the liver dysfunction reduction effect of carbon tetrachloride administration of sweet potato juice containing anthocyanin prepared from purple sweet potato tuberous root from the group of Kyushu Okinawa Agricultural Research Center. The purple sweet potato juice announced contains 12.6 g of purple sweet potato ingredients in 120 ml, and the dosage was 50 mg / kg per day in terms of anthocyanins. It is considered that the functional effect of the product is sufficiently high compared with that (Agricultural Chemistry Society of Japan Annual Meeting 2004, 3A17p10).
Example 10 Confirmation of Tyrosinase Inhibitory Activity
  Tyrosinase inhibitory activity was measured using the sweet potato stem and leaf extract obtained in Example 4. The measuring method is shown below.
(A) Reaction reagent
  Tyrosine solution (0.5 mg / mL): Tyrosine 25 mg was diluted to 50 mL with distilled water and used for measurement.
  Tyrosinase solution (2500 U / mg): 6 mg of mushroom-derived tyrosinase (2500 U / mg) was diluted to 100 mL with distilled water and used for measurement.
  -1/15 M phosphate buffer (pH 6.8): Potassium dihydrogen phosphate 0.9072 g distilled water to 100 mL, sodium hydrogen phosphate 2.3876 g was made up to 100 mL with distilled water. Next, after each equal amount was mixed, it was confirmed that the pH was 6.8 and used for measurement.
  50% v / v ethanol solution: Ethanol and distilled water were mixed in equal amounts and used for measurement.
(B) Preparation of sample object
  10 mg of the sweet potato foliage extract obtained in Example 4 was dissolved in 10 mL of a 50 v / v% ethanol solution to obtain a stock solution. Next, the stock solution was diluted with 1 / 15M phosphate buffer (pH 6.8) to a quantity of 0.005 mg, 0.01 mg, 0.05 mg, 0.1 mg, 0.5 mg, and the reaction Used for.
(C) Tyrosinase activity measurement
  After preparing the following reaction system, it was incubated at 37 ° C. for 1 hour, and the absorbance at 475 nm was measured. As a control (Ab), a tyrosine solution (0.5 mL), a phosphate buffer (4.0 mL), and a tyrosinase solution (0.5 mL) are added to make 5.0 mL. On the other hand, the sample (At) is made 5 mL by adding a tyrosine solution (0.5 mL), a phosphate buffer (2.0 mL), a tyrosinase solution (0.5 mL), and each test solution (2.0 mL).
(D) The tyrosinase activity inhibition rate was calculated using the following formula.
  Inhibition rate = (Ab−At) / Ab × 100
In addition, tyrosinase 50% inhibitory concentration (IC₅₀) Was calculated.
  The tyrosinase inhibitory activity of the sweet potato stem and leaf extract was measured in comparison with kojic acid and ascorbic acid, which have known whitening effects. The results are shown in Table 5.

  Table 5 shows that in vitro tyrosinase activity of the sweet potato stem and leaf extract was measured by in vitro tyrosinase activity. The tyrosinase activity suppression rate at 0.05 mg was 66.40%, which is higher than kojic acid and ascorbic acid. showed that. Moreover, from the result of the inhibition rate, IC₅₀Was estimated to be 0.037 mg.
Example 11 Confirmation of sugar absorption inhibitory effect
  The sugar tolerance test by glucose administration was performed about the sugar absorption suppression effect in the animal experiment using the sweet potato foliage extract obtained in Example 4. The test materials and methods are shown below.
(A) Test animal
  Species: Rat, Strain: SD, Gender: Male, Age at arrival: 4 weeks old
(B) Test group setting
  Control group: 5 animals, 30 mg / kg administration group: 5 animals
(C) Test items and methods
  -The body weight was measured between 10 am and 11 am every day only during the pre-breeding period. In addition, the glucose tolerance test was divided into four groups in consideration of the weight of the previous day.
  -The sweet potato stem and leaf extract was adjusted to each concentration with distilled water and orally administered using a stomach tube.
  ・ Glucose tolerance test was fasted for 18 hours from the day before the test, glucose was orally administered at 2 g / kg, blood was collected from the orbital venous plexus before administration (0 minutes), 30, 60, 90, and 120 minutes after administration, and blood glucose was measured. Measured using a machine. The sweet potato shoot extract was administered 30 minutes before glucose load. In addition, a Δblood glucose area value (AUC: mg / dL · hr) for 120 minutes was calculated from the following calculation formula based on each measurement value.
  a formula
  AUC (0-T4) = C1T1 / 2 + (C1 + C2) (T2-T1) / 2 + (C2 + C3) (T3-T2) / 2 + (C3 + C4) (T4-T3) / 2
  C1: Increase in blood glucose from 0 to 30 minutes
  C2: Blood sugar elevation from 0 to 60 minutes
  C3: Blood sugar elevation from 0 to 90 minutes
  C4: Blood sugar elevation from 0 to 120 minutes
  T: Elapsed time (hr) T1: 0.5 hr, T2: 1.0 hr, T3: 1.5 hr, T4: 2.0 hr
  As a statistical process, the test result is expressed as an average value ± standard error, and the Student's-t test is used for the significant difference test.
  The results of the sugar tolerance test of the sweet potato stem and leaf extract are shown in Table 6.

  The results of Table 6 are shown as a graph in FIG. At 30 minutes after the administration of glucose, the blood glucose level increased most in all groups, but a significant increase suppression was observed in the sweet potato shoot extract administration group compared to the control group. Even after 60 minutes, the value was lower than that of the control group, and a significant difference was observed. In the Δ blood glucose area value (AUC: mg / dL · hr) during 120 minutes of glucose load, the control group showed the highest value, and the sweet potato foliage extract administration group showed a significantly lower value. From the above, the sugar absorption inhibitory action of the sweet potato shoot extract was confirmed.
  Further, under the same conditions as described above, a comparative test with guava leaf extract was performed for the effect of suppressing blood sugar elevation. The test groups were a sweet potato foliage extract 30 mg / kg group, a 100 mg / kg group, a guava leaf extract 100 mg / kg group, and a control group, each of which was performed with 5 rats. Each test object was prepared with physiological saline, and the control group was administered with physiological saline alone.
  Similarly to the above, after administering the test subject, 2 g / kg of glucose was orally administered, blood was collected according to the same blood collection schedule as above, and the blood glucose level was measured. A graph of blood glucose concentration over time based on each measured value is shown in FIG.
  At 30 minutes after glucose administration, the blood glucose level increased most in all groups, but the sweet potato stalk-and-leaf extract group and the guava leaf extract group had a gentle slope of the increase in blood glucose level compared to the control group, It was inferred that each group suppressed sugar absorption. The sweet potato foliage extract 30 mg / kg group showed the same level of blood glucose level as the guava foliage extract 100 mg / kg group, and the sweet potato foliage extract 30 mg / kg group and the 100 mg / kg group were dose dependent. Suppressed increase in blood glucose level. From the above, it was suggested that the sweet potato stalk-and-leaves extract has a stronger antihyperglycemic effect than the guava leaf extract.
Example 12 Confirmation of fat absorption inhibitory action
  A fat tolerance test by administration of soybean oil was conducted for the fat absorption inhibitory effect in animal experiments using the sweet potato foliage extract obtained in Example 4. The test materials and methods are shown below.
(A) Test animal
  Species: Rat, Strain: SD, Gender: Male, Age at arrival: 4 weeks old
(B) Test group setting
  Control group: 5 animals, 30 mg / kg administration group: 5 animals
(C) Test items and methods
  -The body weight was measured between 10 am and 11 am every day only during the pre-breeding period. In addition, the fat tolerance test divided into 4 groups in consideration of the body weight of the previous day.
  -The sweet potato stem and leaf extract was adjusted to each concentration with distilled water and orally administered using a stomach tube.
  ・ Fat tolerance test was fasted for 18 hours from the day before the test, followed by oral administration of 2 g / kg of vegetable (soybean) oil, and orbiting before administration (0 minutes) and 30, 60, 120, 180, 240, 300 minutes after administration. Blood was collected from the venous plexus. The blood was centrifuged (4 ° C., 3000 rpm, 20 minutes) to collect plasma, and the triglyceride concentration was measured using a commercially available kit. The sweet potato shoot extract was administered immediately before the vegetable oil administration. Moreover, (DELTA) neutral fat area value (AUC: mg / dL * hr) for 300 minutes was computed from the following formula based on each measured value.
  a formula
  AUC (0-T4) = C1T1 / 2 + (C1 + C2) (T2-T1) / 2 + (C2 + C3) (T3-T2) / 2 + (C3 + C4) (T4-T3) / 2 + (C4 + C5) (T5-T4) / 2 + (C5 + C6) (T6-T5) / 2
  C1: Triglyceride increase from 0 to 30 minutes
  C2: Triglyceride increase from 0 to 60 minutes
  C3: Triglyceride increase from 0 to 120 minutes
  C4: Triglyceride increase from 0 to 180 minutes
  C5: Triglyceride increase from 0 to 240 minutes
  C6: Triglyceride increase from 0 to 300 minutes
  T: Elapsed time (hr) T1: 0.5 hr, T2: 1.0 hr, T3: 2 hr, T4: 3 hr, T5: 4 hr, T6: 5 hr
  As a statistical process, the test result is expressed as an average value ± standard error, and the Student's-t test is used for the significant difference test.
  Table 7 shows the results of the fat tolerance test of the sweet potato stem and leaf extract.

  The results of Table 7 are shown in FIG. At 60 minutes after administration of the vegetable oil, the sweet potato foliage extract administration group showed a tendency to increase the blood neutral fat concentration, but showed a significantly lower value than the control group. After 120 minutes, the value was almost the same as that of the control group at 60 minutes, but the sweet potato foliage extract administration group showed a low value, but the sweet potato foliage extract administration group had the highest increase at this time point From this, it is inferred that there is a delayed action of fat absorption.
  At 180 minutes and 240 minutes after the vegetable oil administration, the sweet potato shoot extract administration group showed a lower value than the control group, and a significant difference was also observed at 180 minutes. There was no difference between groups after 300 minutes. From the above, in addition to confirming the fat absorption inhibitory action of the sweet potato stem and leaf extract, there is a possibility of having an absorption delaying action.
  Further, under the same conditions as described above, a comparison test with a green tea extract (polyphenol content 30%) was performed with respect to the fat absorption inhibitory action. The test group was a sweet potato foliage extract 30 mg / kg group, a 100 mg / kg group, a green tea extract 30 mg / kg group, and a control group, each of which was performed with 5 rats. Each test object was prepared with physiological saline, and the control group was administered with physiological saline alone. As described above, after administration of the test subject, 2 mg / kg of plant (soybean) oil was orally administered after meal, and blood was collected according to the same blood collection schedule as above.

mg / dL · hr) was calculated as described above and is shown in FIG.
  The sweet potato stem and leaf extract administration group and the green tea extract (polyphenol content 30%) administration group both significantly reduced the amount of neutral fat in the blood, which was increased by intake of soybean oil, as compared to the control group. Comparing the sweet potato stem and leaf extract and the 30 mg / kg administration group of green tea extract, it can be seen that the sweet potato stem and leaf extract has a greater effect of reducing neutral fat in the blood. Moreover, in the sweet potato foliage extract administration group, the amount of neutral fat was reduced in a dose-dependent manner. From the above, it was suggested that the sweet potato stalk-and-leaves extract exerts a neutral fat absorption inhibitory action more strongly than the green tea extract.
Example 13 Toxicity Test of Sweet Potato Forage Extract
  To examine the oral toxicity of a single administration of the sweet potato foliage extract obtained in Example 4, at a dose of 0 mg / kg (control group) and 2000 mg / kg, once for each 5 male and female SD rats per dose. And observed for 14 days. A predetermined amount of a sweet potato shoot extract was weighed and suspended in a 2 v / v% Tween 80 aqueous solution serving as a medium. The dosing solution was prepared once on the day of administration. Observation / measurement items include general state observation (before administration, 30 minutes after administration, 1, 3, 5 hours, then once a day for 14 days), body weight measurement (immediately before administration, 2, 4, 8 , Measured with an electronic pan balance on the 15th), pathological examination (all the 15th day under the anesthesia by intraperitoneal administration of thiopental sodium, the abdominal aorta was cut and exsanguinated and autopsied. ) No deaths occurred in any group and no toxic symptoms developed during the observation period. In addition, no abnormal findings were obtained at autopsy.
Example 14 Production of drinking water (hot water extract) containing sweet potato leaf extract
  By adding a roasting step, the sweet potato foliage extract can be tasted in a range that retains the antioxidant properties of the sweet potato foliage extract. It is possible to adjust the degree of roasting by adjusting the roasting temperature and time.
  A sweet potato leaf (dried product) cut with a cutting machine, roasted moderately (2 minutes 30 seconds) in a pan, and then immersed in hot water (80 ° C.) for 20 minutes to contain a sweet potato leaf extract Created water. Shiroyutaka has large leaves and a large dry weight, so it was easy to handle in roasting and other processes. By passing through the roasting process, it was possible to impart a fragrant fragrance and taste to the drinking water (sweet potato stem and leaf extract) compared to the case of not roasting. It is thought that this is also due to the formation of quinic acid, which is a degradation product of chlorogenic acid contained in sweet potato leaves. In addition, the taste and aroma can be subtly changed depending on the temperature of the water to be extracted. The roasted sweet potato foliage can also be used as an extraction raw material of the present invention. For example, 4 grams of roasted sweet potato foliage are packed in a tea pack and immersed in approximately 2 liters of hot water for easy drinking. Water (sweet potato foliage extract) can be obtained, and drinking water with good aroma and taste that can exhibit various excellent effects of the sweet potato foliage extract can be produced.
Example 15 Mutagenicity test of sweet potato stem and leaf extract
(1) Ames test
  The effect of mutagenicity in vitro was determined by the “Ames test” in accordance with the Guidelines for Drug Genotoxicity Testing. Five strains of Salmonella typhimurium (TA100, TA98, TA1535, TA1537) and Escherichia coli (WP2uvrA / pKM101) were used as assay bacteria. The sweet potato foliage extract (test sample) 5000 μg / plate obtained in Example 4 was used as the highest dose, and a dose response test was conducted in 6 steps (1.22 to 500) for each of the S9mix addition and non-addition groups. Since no growth inhibition of the fungus was observed, this test was also carried out with 5 doses set at 5000 μg / plate as the maximum dose, and the number of revertant colonies at each concentration was measured. As a result, according to the determination method of the Ames test, mutagenicity was determined to be negative regardless of the presence or absence of S9mix in any of the test bacteria.
(2) Micronucleus test
  The in vivo mutagenic effect of the sweet potato stem and leaf extract was determined by the “micronucleus test using rodents” in accordance with the Guidelines for Drug Genotoxicity Testing. The sweet potato foliage extract (test sample) 500, 1000, and 2000 mg / kg obtained in Example 4 was administered twice orally to male rats (7 weeks of age, 5 animals / group) using three doses each (24 As a result of the time interval, there was no death in any group, and there was no change in the general condition. Therefore, in this test, the test sample was set to the same concentration, and cyclophosphamide 10 mg / kg was added to the positive subject and physiological saline was added to the negative subject. Twenty-four hours after the final administration, bone marrow cells were collected from the femurs of test animals to prepare tissue specimens. As a result of measuring the ratio of red blood cells with micronuclei in total red blood cells by a standard method and applying statistical processing, the frequency of micronuclei was not statistically significant for the test sample, and the mutagenicity was judged to be negative. It was.
  The above results indicate that the mutagenicity of the sweet potato foliage extract was negative in all tests, suggesting that the ingestion of the sweet potato foliage extract is unlikely to cause mutation and is extremely safe. .
Example 16 Deodorizing effect test of sweet potato stem and leaf extract
  We examined the deodorizing effect on causative substances such as bad breath, body odor, and fecal odor of humans and pets.
(1) Ammonia, trimethylamine, and mercaptan were added to 100 ml pure water in a 300 ml conical beaker, and the lid was covered with aluminum foil.
(2) The concentration of each component in the headspace portion was measured with a detector tube, 1 g of the sweet potato shoot extract obtained in Example 4 was added and stirred, and the concentration of each component in the headspace portion was measured with a detector tube. .
  The measurement results are shown in FIG. As for ammonia and trimethylamine, no odor was felt immediately after adding the sweet potato shoot extract, and the concentrations were below the detection limit. In addition, methyl mercaptan was partially decomposed immediately after the addition of the sweet potato shoot extract, and a deodorizing effect was observed. From the above, it was suggested that the sweet potato shoot extract exerts a deodorizing effect on different kinds of odors. Since the sweet potato stem and leaf extract has been confirmed to be extremely safe for living bodies by the safety test of the present invention, it eliminates bad breath, body odor and fecal odor of humans and pets, and deodorizes food and drink. Among substances having a deodorizing effect, it can be said that the substance can be used in a very wide range of applications.
Example 17 Adipocyte differentiation and hypertrophy inhibition test using rat white adipocytes
  In order to examine the effect of suppressing the increase in adipocytes, a test for suppressing differentiation and hypertrophy of white adipocytes derived from rat mesentery in vitro was performed.
Observation of adipocyte differentiation and suppression of hypertrophy in rat white adipocytes
  The fat cells of the rat white fat cell kit (Cell Garage Co., Ltd.) were used, and all operations were performed according to the usual method. First, adipocytes are grown in growth medium with 5% CO2.₂Incubation was carried out for 24 hours. 2 × 10 fat cells⁵After inoculating into a 24 well plate so as to be cells / well and incubating for 24 hours, the medium is replaced with a differentiation-inducing medium, and 5% CO 2 is added.₂Incubated for 48 hours. Further, after replacing the adipocyte maintenance medium, 100 μg / mL of the sweet potato leaf extract obtained in Example 4 and 100 μg / mL of the green tea extract (90% catechin) were added to the adipocytes in the medium as test objects. As a control, nothing added, 5% CO₂A lower incubation was performed and the state of the cells was observed every 24 h.
  The states after 24 hours, 72 hours and 96 hours of each group of adipocytes are shown in FIG. As a result, the sweet potato stem and leaf extract and the green tea extract both remarkably suppressed the accumulation of fat cell fat droplets and fat cell hypertrophy over all times compared to the control. Comparing the sweet potato stem and leaf extract with the green tea extract, the accumulation of lipid droplets in the green tea extract was slightly less after 24 hours, but both were the same after 48 hours (data not shown) and after 72 hours. After the time, the sweet potato foliage extract was the same or slightly suppressed the fat cell hypertrophy. From the above, it was found that the sweet potato stem and leaf extract has substantially the same or higher effect of suppressing adipocyte differentiation and hypertrophy than the green tea extract. Therefore, it was suggested that the sweet potato shoot extract of the present invention can be used as a prophylactic / therapeutic agent for obesity caused by adipocyte differentiation and hypertrophy.
Example 18 Examination of antidepressant action and anti-fatigue action by mouse forced swimming method
  We investigated the antidepressant action and anti-fatigue action of sweet potato stem and leaf extract by forced swimming of mice.
  Mice (BALB / c strain, male, 7 weeks old) were acclimated by preliminary breeding for 7 days until the day before the start of this test. 2 days before the end of the pre-breeding, the test animals are forced to swim for 5 minutes and screened so that the swimming state before administration of the test object is uniform. The test was started after grouping. The test groups were the sweet potato leaf extract 30 mg / kg group, the 300 mg / kg group, the St. John's wort 300 mg / kg, and the subject group obtained in Example 4. Each test object was prepared in physiological saline and administered by oral gavage (10 mL / kg) using a stomach tube. For the control group, physiological saline was similarly administered by gavage (10 mL / kg). One hour after administration of the test object, swimming was performed in an acrylic water tank (350 × 400 × 180 mm) filled with 10 L of warm water (37 ° C.), and the swimming state was observed. The determination was made by measuring the duration according to the following criteria.
Judgment criteria
  EDB (escape directed behavior): An action to jump out of a water tank or an action to search for an exit by diving
  IMO (Immobility): The state where most movements are stopped and only floating
  The average values of EDB and IMO time for each group are shown in FIG. In the sweet potato foliage extract and St. John's wort extract administration groups, a significant increase in EDB and a significant shortening of IMO were observed with respect to the control group. Further, the sweet potato foliage extract administration group showed a concentration-dependent effect, and the sweet potato foliage extract 300 mg / kg group showed almost the same effect as the St. John's wort 300 mg / kg group. St. John's wort is widely known as a herbal that relaxes mood and is effective in stress, and is actually used in Germany as an antidepressant for mild to moderate depressive symptoms. Like the St. John's wort group, the sweet potato foliage extract group was effective against forced exercise and mental stress. It is effective against general stress and fatigue, and has an antidepressant action, anti-stress action, and relaxation action, which is almost the same as St. John's wort.
Example 19 Oil stability test
  The sweet potato foliage extract obtained in Example 4 was added to 3 g of pork fat free of vitamin E so as to be 200 ppm and 1000 ppm, respectively, and used as a sample solution. The deterioration start time of fats and oils was calculated | required by the automatic oil-fat stability test apparatus (CDM test apparatus) with the dry air flow rate of 20 L / hr and the temperature of 120 degreeC.
  The deterioration time in the concentration of sweet potato stem and leaf extract is shown in FIG. The sweet potato stem and leaf extract extended the deterioration time of 1.6 hours at 0 ppm, doubled the deterioration time of pork fat at 200 ppm, and tripled it at 1000 ppm (5 hours). Extended. From the above, sweet potato stem and leaf extract is added to processed foods (fried potatoes, snacks, cup noodles, etc.) that use animal lipids such as pork fat and lard and other various fats and oils, and is applied to prevent fat and oil deterioration It was suggested that this could be done.
Example 20 Preparation of a preparation using a sweet potato shoot extract
The following three types of preparations were prepared using the sweet potato stem and leaf extract of the present invention.
(1) Preparation of granules
As shown in Table 8 below, the sweet potato foliage extract is mixed with various excipients to a final concentration of 5%, and a total amount of 2 kg of raw materials are added and kneaded, and then the spray drying granulator is used. Granules were prepared using these. The produced granules were packaged in aluminum every 2 grams. Since this product is convenient to carry and has good water solubility, it can be made into a delicious beverage by dissolving in about 100 mL of hot water or water at the time of use. This product contains 100 mg of sweet potato stover extract per packet.

(2) Preparation of tablets
As shown in Table 9 below, 1 kg of sweet potato foliage extract is mixed with various excipients so that the final concentration is 20%, and after adding a suitable amount of water based on a total of 5 kg of raw materials, kneading and pressing A tablet of 250 mg was prepared using a tablet manufacturing machine. This product contains 50 mg of sweet potato stover extract per tablet.

(3) Gummy production
As shown in Table 10 below, 10 g of sweet potato stem and leaf extract is mixed with 1 kg of gummy base under heating, and boiled until the sugar content reaches about 80%. A citric acid solution and fruit juice and flavor were added, and the resulting mixture was molded into 5 g per grain while hot (sweet potato stem and leaf extract final concentration 0.1%). This product contains 5 mg of sweet potato stem and leaf extract per grain.

  The sweet potato stem and leaf extract can be added or subtracted as needed depending on the purpose, and it can be easily mixed with other functional ingredients, food and drink ingredients, and fragrances. It has been found that it is excellent in handling as a functional material and has a very wide application range. Moreover, it can be said that it can be used widely as a material for food and drink.

ADVANTAGE OF THE INVENTION According to this invention, the water-soluble sweet potato stem and leaf extract containing the polyphenol which has various beneficial activity for a human body can be provided. The sweet potato stem and leaf extract of the present invention has activities or actions such as antioxidant activity, tyrosinase inhibitory activity, hepatoprotective action, sugar or neutral fat absorption inhibitory action, etc., so a functional food having such functions and actions It is useful as a functional material, medicine and the like.
Moreover, according to the method for producing a polyphenol-containing sweet potato foliage extract of the present invention, a polyphenol-containing extract can be efficiently obtained without using special materials or facilities.

Claims (29)

A water-soluble extract derived from sweet potato foliage, wherein the polyphenol content is 10% or more. The sweet potato shoot extract according to claim 1, wherein the polyphenol content is 20% or more. The sweet potato foliage extract according to claim 1 or 2, which contains at least quercetin-3-glucoside as a component of polyphenol. 4. The sweet potato shoot extract according to claim 1, wherein the content of quercetin-3-glucoside in the polyphenol is 1% or more of the sweet potato shoot extract. 5. The sweet potato foliage extract according to any one of claims 1 to 4, comprising at least quercetin-3-glucoside and 3,5-dicaffeoylquinic acid as components of polyphenol. A water-soluble extract derived from sweet potato stems and leaves, which contains at least quercetin-3-glucoside and 3,5-dicaffeoylquinic acid as polyphenol components. A water-soluble extract derived from sweet potato foliage, which contains at least quercetin-3-glucoside, chlorogenic acid and 3,5-dicaffeoylquinic acid as polyphenol components. A step of extracting sweet potato stems and leaves with a water-containing organic solvent, and a step of removing the organic solvent from the extract obtained by the extraction step to obtain a water fraction, comprising water-soluble sweet potato stems and leaves containing polyphenols A method for producing an extract. The manufacturing method of Claim 8 which further includes the process of refine | purifying polyphenol after the said process. The production method according to claim 8 or 9, comprising a step of any one of drying, crushing, heating and roasting of sweet potato foliage, or a combination thereof as a previous step. The method according to any one of claims 8 to 10, wherein the water-containing organic solvent is ethanol and the content is 40 to 90%. The production method according to claim 8, wherein the ethanol content is 60%. A water-soluble sweet potato foliage extract containing polyphenols obtainable by the production method according to claim 8. It is obtainable by the production method according to any one of claims 8 to 12, has a polyphenol content of 10% or more, and contains at least quercetin-3-glucoside as a component of the polyphenol. Sweet potato stem and leaf extract. A water-soluble sweet potato stem-and-leaf extract obtainable through a step of water-extracting sweet potato stems and leaves, having a polyphenol content of 10% or more and containing at least quercetin-3-glucoside as a component of the polyphenol Water-soluble sweet potato stem and leaf extract. The water-soluble sweet potato shoot extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14 or 15, wherein the sweet potato variety belongs to white sweet potato. The water-soluble sweet potato shoot extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15 or 16, characterized in that the sweet potato variety is White Yutaka. Claims 1, 2, 3, 4, 5 including the step of any one of drying, crushing, heating, roasting of sweet potato foliage, or a combination thereof in the previous stage of the production process of the sweet potato foliage extract , 6, 7, 13, 14, 15, 16 or 17 Water-soluble sweet potato stem and leaf extract. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient Functional food and drink. The functionality according to claim 19, which has one or more of the functions of antioxidant, liver protection, tyrosinase inhibition, sugar absorption inhibition, neutral fat absorption inhibition, obesity prevention / improvement, antidepressant, and anti-fatigue. Food and drink. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient Functional material. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient A pharmaceutical product. 23. The pharmaceutical product according to claim 22, which has one or more of the following effects: antioxidant, hepatoprotection, tyrosinase inhibition, sugar absorption inhibition, neutral fat absorption inhibition, obesity prevention / improvement, antidepressant, antifatigue. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient Antioxidant. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient Deodorant. A water-soluble sweet potato foliage extract containing polyphenols or a sweet potato foliage extract according to claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 or 18 as an active ingredient Deterioration preventive agent for fats and oils and fat-containing foods. Drinking water containing 0.01 mg / ml to 30 mg / ml of a water-soluble sweet potato shoot extract as a polyphenol content. Food / beverage products containing the water-soluble sweet potato foliage extract of Claim 1, 2, 3, 4, 5, 6, 7, 13, 14, 15, 16, 17, or 18. Soft drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, tea drinks, concentrated drinks, nutrition drinks, alcoholic drinks, fats and oils, processed foods, noodle breads, seasonings, confectionery (water confectionery, jelly, yogurt, gummy Or the food or drink according to claim 27 or 28, which is a dietary supplement.

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