JP2012020993A - Glucagon-like peptide-1 secretagogue - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effective factor for promoting the secretion of glucagon-like peptide-1.SOLUTION: There is provided the glucagon-like peptide-1 secretagogue including a sweet potato foliage processed product. The glucagon-like peptide-1 secretagogue is useful for preventing and ameliorating diabetes and obesity that is preferably utilized for drug product or food and drink.

Description

  The present invention relates to a glucagon-like peptide-1 secretion promoter.

  Glucagon-like peptide-1 (hereinafter also referred to as “GLP-1”), a hormone secreted from L cells scattered in the gastrointestinal tract, promotes insulin secretion by stimulating food, stimulates the satiety center, and peristalsis of the gastrointestinal tract It has been confirmed that it has an action such as suppression. All of these actions of GLP-1 are considered to be related to the effect of suppressing a rapid increase in blood glucose level due to feeding, and studies have been conducted on the use of GLP-1 for the treatment of diabetes. GLP-1 is also attracting attention for its obesity-inhibiting action.

  Therefore, development of therapeutic agents utilizing the anti-diabetic action or anti-obesity action of GLP-1 is expected. However, since GLP-1 has very low stability in the body, it is necessary to optimize administration methods and administration routes, search for functional analogs having high stability in the body, and the like.

  Therefore, research is being conducted on substances that promote GLP-1 secretion in the digestive tract instead of directly administering GLP-1. Several naturally-occurring components having a GLP-1 secretion promoting effect are known. For example, Patent Document 1 discloses that acid casein and the like have a GLP-1 secretion promoting action. Patent Document 2 discloses that casein glycomacropeptide (CGMP) has a GLP-1 secretion promoting action. Patent Document 3 discloses a GLP-1 secretion promoter containing κ-casein as an active ingredient. Non-Patent Document 1 discloses that peptide ZeinH obtained by hydrolyzing maize indigestible protein Zein with papain has a GLP-1 secretion promoting action.

  By the way, it has been clarified that sweet potato stalks and leaves contain components effective for health such as vitamins and minerals, and is beginning to be used as a food raw material for the purpose of preventing lifestyle-related diseases. It has also been clarified that sweet potato stems and leaves contain polyphenols such as chlorogenic acid, tricaffeoylquinic acid, and dicaffeoylquinic acid (Patent Document 4). Attention has been paid to the functionality of sweet potato stems and leaves, and their effective use is being studied earnestly. So far, preparation and utilization of processed sweet potato foliage (Patent Document 5); extract of sweet potato foliage (Patent Document 4); and antihypertensive agent (Patent Document 6) of processed sweet potato foliage (Patent Document 6) 7), use as an anti-obesity agent (Patent Document 8), an agent for preventing diabetes or diabetic complications (Patent Document 9), and an inhibitor of lipid accumulation in the liver (Patent Document 10).

European Patent Application Publication No. 1367065 International Publication No. 01/37850 International Publication No. 2007/037413 JP 2006-8665 A No. 2005/112665 publication JP 2005-330240 A JP 2006-6317 A JP 2006-306852 A JP 2007-119346 A JP 2008-208030 A

Toru Hira, “33. Search for Food Peptides that Stimulate Secretion of GLP-1 Promoting Insulin Secretion, and Elucidation of the Gastrointestinal Receptor”, Uehara Memorial Life Science Foundation, 22 (2008)

  An object of the present invention is to provide a useful glucagon-like peptide-1 secretion promoter.

  The present invention provides a glucagon-like peptide-1 secretion promoter containing a processed product of sweet potato stover.

  In one embodiment, the processed sweet potato foliage is a sweet potato stover extract obtained by extracting sweet potato stover with water or water-containing ethanol.

  In a further embodiment, the hydrous ethanol is hydrous ethanol having an ethanol content of less than 80% by volume.

  According to the present invention, a novel glucagon-like peptide-1 secretion promoter is provided. This glucagon-like peptide-1 secretion promoter can be useful for the prevention and improvement of diabetes and obesity, and can be suitably used for pharmaceuticals and foods and drinks.

GLP-1 secretion amount of GLP-1 producing cell line GLUTag derived from mouse large intestine by each treatment of sweet potato stalk and leaf powder, sweet potato stalk and leaf hot water extract, sweet potato stalk and leaf hydrous ethanol extract, and sweet potato stalk and leaf pepsin degradation product in a bar graph FIG. Sweet potato stalks and leaves hot water extract, fraction 1 (water-soluble-activated carbon adsorbed fraction), fraction 2 (water-soluble-activated carbon non-adsorbed fraction), fraction 3 (water-insoluble-60 vol% ethanol-soluble fraction), It is the figure which represented the amount of GLP-1 secretion of the mouse | mouth colon-derived GLP-1 production cell strain GLUTag by each process of and fraction 4 (water insoluble-60 volume% ethanol insoluble fraction) with the bar graph.

  The glucagon-like peptide-1 (GLP-1) secretion promoter of the present invention contains a processed product of sweet potato foliage. The processed sweet potato leaves used in the present invention will be described below.

(1) Sweet potato stem and leaf Sweet potato refers to a plant belonging to the convolvulaceae family and is generally called sweet potato. The variety of sweet potato is not particularly limited. For example, varieties such as Suiou, Joy White, Koganesengan, Shiroyutaka, Satsuma Musti, Ayamurasaki and the like can be mentioned. As used herein, “sweet potato stem and leaf” refers to “at least one of sweet potato stem and sweet potato leaf”, and includes only sweet potato leaf, only sweet potato stem, and both sweet potato stem and leaf. What sieved to the leaf part and the stem part may be used, and what is not sieved may be used.

  As the sweet potato stalks and leaves, it is preferable to use the stems or leaves that are exposed from the ground during the cultivation of sweet potatoes. In particular, sweet potato stems and leaves grown to 5 cm or more from the ground, preferably 10 cm or more, more preferably 20 cm or more are preferable. In addition, when the length from the position where the candy stalk is out of the ground to the tip of the candy shoot is measured, the length is 300 cm or less, preferably 200 cm or less, more preferably 150 cm or less. Is preferred.

  Further, as the sweet potato stalks and leaves, the tip part of the sweet potato stalks and leaves (“sweet potato young stalks and leaves”) is preferable. As the sweet shoots of sweet potatoes, the shoots and leaves of a portion within 60 cm from the tip of the sweet potato shoots are preferably used. The sweet potato leaves are easy to process because the plants themselves are soft. Furthermore, when the young shoots of sweet potato stems and leaves are dried powder, they have a good touch and can be easily used for various foods.

  In the present invention, “Suio” stems and leaves having a high polyphenol content are particularly preferred. Since Suiou is characterized by the fact that young shoots of sweet potato are regenerated from the tip of the same stem even after harvesting the stems and leaves, Suiou can be suitably used.

  The stems or leaves of sweet potatoes (especially Suio) are rich in dicaffeoylquinic acid and tricaffeoylquinic acid, which are polyphenols. For example, the leaves of Suiou contain 1 mg to 300 mg of tricaffeoylquinic acid per 100 g of dry mass. Sweet potato foliage (especially Suiou foliage) is particularly rich in tricaffeoylquinic acid compared to other plants.

(2) Processed sweet potato foliage The sweet potato foliage can be processed (treated) from the standpoints of quality stability and long-term storage. In the present specification, the “processed sweet potato stem and leaf product” refers to a sweet potato stem and leaf that has been subjected to some processing (treatment). Examples of the treatment include heat treatment, drying treatment, powdering treatment, pressing treatment, and extraction treatment. Only one kind of these treatments may be performed, or two or more kinds may be performed. The harvested sweet potato stalks and leaves can be subjected to these treatments after washing adhering mud and the like with water. Hereinafter, the treatment of sweet potato stems and leaves will be specifically described.

(2-1) Heat treatment The heat treatment is performed for the purpose of stabilizing the quality due to inactivation of the enzyme in the sweet potato stem and leaves and preventing the sweet potato stem and leaves from fading. Examples of the heat treatment include blanching treatment, dry heat treatment, microwave treatment, infrared or far infrared treatment, and steam treatment. Of these heat treatments, blanching treatment and steam treatment are preferably used. Furthermore, for the convenience of the treatment process, each treatment may be performed after cutting the sweet potato stems and leaves into a major axis of about 3 to 30 cm as necessary.

  When performing the blanching treatment, a method commonly used by those skilled in the art may be used in order to prevent the color of chlorophyll (sweet potato leaves) that is a pigment of green plants from fading. Examples of such a blanching process include blanching and spraying processes. In the blanching treatment, the optimum conditions vary greatly depending on the plant used. In some cases, the blanching process may damage the flavor and nutrients and lose the physiological activity of the useful ingredients. Therefore, in the present invention, heat treatment (for example, 1 to 10) is performed with hot water (for example, 85 ° C. or more) adjusted to pH 5.4 to 8.5, preferably 6.0 to 8.0, more preferably 7.0. Minutes).

  When heat treatment is performed by dry heat treatment, microwave treatment, infrared or far-infrared treatment, and steam treatment, the heat treatment is performed after performing pH adjustment treatment such as spraying a solution with adjusted pH on sweet potato leaves. It is preferable.

  The pH adjustment treatment is performed by a method commonly used by those skilled in the art. For example, when adjusting to basic conditions, sodium hydroxide, baking soda, magnesium carbonate, calcium carbonate (eg, eggshell calcium, scallop shell calcium, coral calcium), calcium oxide (obtained by baking calcium carbonate), etc. A solution may be used. Of course, alkaline ionized water or the like may be used. On the other hand, when adjusting to acidic conditions, the solution of organic acids, such as an acetic acid, a citric acid, ascorbic acid, tartaric acid, malic acid, and fumaric acid, may be used. What is necessary is just to adjust the quantity of these pH adjusters suitably with the adjuster to be used.

  The heating temperature in the heat treatment is higher than 80 ° C., preferably 85 ° C. or higher, more preferably 90 ° C. or higher. The heating time in the heat treatment is 10 minutes or less, preferably 5 minutes or less, more preferably 3 minutes or less, and even more preferably 10 seconds to 1 minute.

  In order to maintain the green color and flavor, it is preferable to immediately cool the sweet potato stalks and leaves after the heat treatment. Cooling may be performed by a method commonly used by those skilled in the art, such as immersing the sweet potato stems and leaves after heat treatment in cooling water or quenching them with cold air. For example, when cooling by immersing in cooling water, water at 30 ° C. or lower may be used.

(2-2) Drying treatment The drying treatment is preferably performed in order to maintain the quality of the sweet potato stover before processing. The drying treatment is carried out using any drying method commonly used by those skilled in the art after the sweet potato stems and leaves are preferably subjected to the above-mentioned heat treatment, or after being made into a paste or pressed into juice. The drying process is performed according to a drying method, for example, a hot air dryer, a high-pressure steam dryer, an electromagnetic wave dryer, a freeze dryer, a vacuum concentrator, a spray dryer, a direct-fired heater, a rotary draft dryer. Etc. are performed.

  Among these, a hot air dryer, a direct-fired heater, and a rotary draft dryer are preferably used for the drying treatment of sweet potato stems and leaves from the viewpoint of production cost and drying efficiency.

  The drying treatment at normal pressure is preferably performed at 60 ° C. to 150 ° C., preferably 70 ° C. to 100 ° C., in that a sweet and colorful sweet potato stalk dry powder is obtained. The drying treatment under reduced pressure is preferably performed at 60 ° C. or less, preferably at or above the temperature at which the sweet potato stover, its paste or juice is frozen, and at 60 ° C. or less in terms of reducing loss of nutrients. .

  The drying treatment is preferably performed so that the moisture content in the dried product is 5% by mass or less.

  When the sweet potato stover is dried as it is, it is preferably performed in two stages. The two-stage drying can be performed using, for example, a hot air dryer. In the two-stage drying, first, primary drying is performed at a temperature of 60 to 80 ° C. until the water content becomes 25% by mass or less. Next, secondary drying is performed at a temperature higher than the primary drying until the water content of the primary dried sweet potato leaves becomes 5% by mass or less.

  At this time, when the drying temperature of primary drying is less than 60 ° C., the drying speed is slow, and when the drying temperature of secondary drying exceeds 100 ° C., charring may occur. Therefore, the secondary drying temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, 85 ° C. or lower, and further preferably about 80 ° C.

  In addition, it is preferable that the temperature difference of primary drying and secondary drying is about 5-15 degreeC, and it is more preferable that it is about 10 degreeC. For example, when secondary drying is performed at 90 ° C., the primary drying temperature is preferably 75 to 85 ° C., more preferably about 80 ° C.

  By performing the two-stage drying process, the drying time is shortened, and at the same time the green color and flavor of the sweet potato leaves are maintained. By setting the temperature difference within a certain range as described above, moisture management of sweet potato stem leaves (especially green leaves) in the drying process is facilitated, and drying is performed efficiently.

  In the case of using a rotary dryer, for example, sweet potato foliage is once crushed using a food processor or a mascolloider and made into a paste. In this case, as in the case of pulverizing the sweet potato stems and leaves, it is preferable to use a mascolloider after crushing once with a food processor. A sweet potato foliage powder having a water content of 5% by mass or less can be obtained by charging the rotary drum at a heating temperature of 100 ° C. to 150 ° C., preferably 110 ° C. to 130 ° C. Furthermore, since the heating temperature is high, sterilization can be performed at the same time. In this case, the heating time is preferably about 30 seconds to 2 minutes because the sweet potato foliage may be discolored.

(2-3) Powdering treatment The powdering treatment can be performed on either dried or undried sweet potato foliage. The sweet potato stems and leaves are preferably subjected to the above heat treatment. The dried sweet potato stalks and leaves can be subjected to a pulverization treatment to obtain a dried sweet potato stalks and leaves. Undried sweet potato leaves can be crushed into fine pieces, pastes, etc., and then subjected to a drying treatment to produce sweet potato leaves. Since sweet potato stems and leaves are composed of stems and leaves (including leaf blades and petiole parts), the pulverization treatment is preferably performed through a coarse pulverization step or a fine pulverization step from the viewpoint of increasing the pulverization efficiency.

  Coarse pulverization is, for example, a process in which a dried product of sweet potato stover is cut by a machine or tool commonly used by those skilled in the art, such as a cutter, a slicer, or a dicer. The major dimension of the cut size is preferably 20 mm or less, and more preferably 0.1 to 10 mm. Note that this step may be omitted when a paste-like crushed material is used.

Although the fine pulverization step can be performed following the coarse pulverization step, a sterilization step may be performed before the fine pulverization step. By sterilization, the coarsely crushed sweet potato stalks and leaves can be heated uniformly, and efficient sterilization can be performed while improving the flavor of the sweet potato stalks and leaves (especially green leaves). Sterilization is performed at 110 ° C. or higher using a high-pressure sterilizer, a heat sterilizer, a pressurized steam sterilizer, or the like. For example, in the case of sterilization using a pressurized steam sterilizer, the coarsely crushed sweet potato stalks and leaves are exposed to 110 to 200 ° C. saturated steam for 2 to 10 seconds under a pressure of 0.5 to 10 kg / cm ² , for example. If necessary, the water adhering to the sweet potato stems and leaves in the sterilization process is further removed.

  The pulverization step is performed so that 90% by mass passes through the 200 mesh section. The pulverization is performed by using a machine or an apparatus usually used by those skilled in the art, such as a crusher, a mill, a blender, and a stone mill. By finely pulverizing, the texture of sweet potato stems and leaves is improved. Preferably, the texture is further improved by sequentially performing steps of coarse pulverization, sterilization, and fine pulverization.

(2-4) Squeezing treatment After sweet potato stover is preferably subjected to the above heat treatment, it can be subjected to a squeezing machine or the like to obtain juice.

  When the obtained juice is used as it is without being subjected to the above-described drying treatment and powdering treatment, it undergoes the sterilization step (for example, sterilization by a heat sterilizer at 80 to 130 ° C.) described above. It is preferable.

  When obtaining dry powder from squeezed juice, the obtained squeezed juice is dried using a heat dryer, a vacuum concentrator, a freeze dryer or the like. What is necessary is just to grind | pulverize the obtained dried material. For example, if a spray dryer such as a spray dryer is used, it is powdered simultaneously with drying. When spray drying is performed, an excipient such as dextrin, cyclodextrin, starch or maltose is added as necessary to increase the recovery rate. Preferably dextrin is used. The mass ratio of squeezed juice and dextrin is not particularly limited, but is preferably 1:10 to 5: 1 in order to facilitate powdering by addition of dextrin.

(2-5) Extraction treatment Extraction is performed by bringing a sweet potato foliage or a sweet potato foliage that has been subjected to at least one of the above-described heat treatment, drying treatment, powdering treatment, pressing treatment, and the like with a solvent. Can be performed.

  Examples of the extraction solvent include water, an organic solvent, and a water-containing organic solvent. Preferably, water or a water-containing organic solvent can be used. In the present specification, the “hydrated organic solvent” refers to an organic solvent containing water, and the water and the organic solvent may be compatible or incompatible. That is, the water-containing organic solvent may be a mixture of water and an organic solvent before extraction, or a mixture of water and an organic solvent during extraction (for example, by stirring).

  Water is not particularly limited. For example, spring water, well water, distilled water, tap water, pure water, or the like can be used.

  Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, hexane, cyclohexane, propylene glycol, ethyl methyl ketone, glycerin, methyl acetate, ethyl acetate, and diethyl ether. , Dichloromethane, edible fats and oils, 1,1,1,2-tetrafluoroethane, 1,1,2-trichloroethane and the like. In the present invention, among these organic solvents, polar organic solvents such as alcohols (methanol, ethanol, etc.) are preferable. More preferred is ethanol.

  The hydrous organic solvent is preferably a hydrous polar organic solvent such as hydrous alcohol, more preferably hydrous ethanol. The ratio of the organic solvent contained in the water-containing organic solvent is not particularly limited, but may be preferably less than 80% by volume, more preferably less than 70% by volume.

  In the case of hydrous ethanol, hydrous ethanol containing ethanol by less than 80% by volume, preferably 10% by volume to 70% by volume, more preferably 20% by volume to 60% by volume may be used.

  Although extraction temperature may depend on an extraction solvent, 4 degreeC or more is preferable and 10 degreeC or more is more preferable. For example, extraction can be performed at temperatures of 25 ° C. or higher, 50 ° C. or higher, 70 ° C. or higher, 90 ° C. or higher, 95 ° C. or higher, 100 ° C. or higher, 121 ° C. or higher, and 130 ° C. or higher. Moreover, 150 degrees C or less is preferable and 100 degrees C or less is more preferable. When the boiling point is reached under atmospheric pressure depending on the solvent used, extraction may be performed at a predetermined temperature by applying pressure.

  The extraction time may depend on the extraction temperature and the extraction solvent, but is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more. Moreover, Preferably it is 72 hours or less, More preferably, it is 48 hours or less.

  For example, when the extraction solvent is water or hydrous ethanol, the extraction is performed at 4 ° C. to 100 ° C., preferably 10 ° C. to 100 ° C., for 10 minutes to 72 hours, preferably 30 minutes to 48 hours, more preferably 2 hours. This can be done by holding for ~ 48 hours.

  Next, a method for producing an extract using sweet potato stover and a solvent will be described. In order to produce the extract, it is necessary to contact the sweet potato stover and the solvent. Although the method of the contact is not specifically limited, For example, a sweet potato shoot and a solvent can be contacted using a chemical engineering extraction method (solid-liquid extraction method). And as a chemical engineering extraction method, the following method 1 and method 2 are mentioned, for example.

  Method 1: A method in which the components of sweet potato foliage are dissolved in the solvent by allowing the solvent to permeate and reflux in the stationary solid layer (in the sweet potato foliage layer).

  Method 2: A method in which a solid (sweet potato foliage) is dispersed or immersed in a solvent and components of the sweet potato foliage are dissolved in the solvent.

  In “Method 2”, the sweet potato foliage can be dispersed or immersed in a solvent adjusted to a predetermined temperature, and the components of the sweet potato foliage can be dissolved in the solvent. The temperature of the solvent adjusted to the predetermined temperature is preferably the temperature at which the solvent is refluxed (that is, the boiling point), but is not limited thereto. Even during the extraction, it is preferable to dissolve the components of the sweet potato leaves in the solvent while maintaining the temperature of the solvent and refluxing the solvent. This is because maintaining the temperature of the solvent stabilizes the quality and quantity of the extract obtained.

  The extraction solvent can be used in an appropriate amount, preferably 100 mL or more, more preferably 400 mL or more, and preferably 2500 mL or less with respect to 50 g of the dry mass of sweet potato stems and leaves. The amount of solvent used may be divided and used for multiple extractions. Specifically, 1000 mL of solvent may be used for one extraction, or 500 mL may be divided and used for two extractions.

  The sweet potato stem and leaf extract has, for example, water or ethanol content of less than 80% by volume, preferably 10% to 70% by volume, more preferably 20% to 60% by volume, based on 1 part by weight of the sweet potato stem and leaf. % Hydrous ethanol can be added in an amount of 0.5 to 100 parts by mass, preferably 0.5 to 50 parts by mass. In addition, it is possible to extract a low polar component and a high polar component efficiently by using 60 volume% hydrous ethanol.

  In one embodiment, the sweet potato stover extract may be prepared according to Preparation Example 1 or 2 below, but with some modifications. Briefly, an appropriate amount of pure water is added to 50 g of dried sweet potato stalks and leaves obtained by the above heat treatment, drying treatment and powdering treatment, and at normal temperature (for example, 20 ° C.) or at the boiling point. An extract can be produced by sufficiently placing it in a boiling water bath in an oil bath at a temperature in the vicinity (for example, 98 ° C.) and collecting the liquid after the solid-liquid separation. Furthermore, according to the following Preparation Example 5, the obtained liquid (water-soluble fraction) is treated with activated carbon and fractionated into a water-soluble activated carbon adsorbed fraction and a water-soluble activated carbon non-adsorbed fraction, or According to the following Preparation Example 6, an appropriate amount of water-containing ethanol is added to the residue after the solid-liquid separation (water-insoluble fraction), and fractionated into a water-insoluble-ethanol-soluble fraction and a water-insoluble-ethanol-insoluble fraction. By doing so, an extract can be produced. Alternatively, an appropriate amount of water-containing ethanol is added to 50 g of dried sweet potato leaves obtained by the above heat treatment, drying treatment and pulverization treatment, and the mixture is sufficiently placed at room temperature (for example, 20 ° C.), followed by solid-liquid separation. By recovering the later liquid, an extract can be produced.

  The obtained extract may further be used as a concentrated extract or extract powder by evaporating the solvent after completion of the extraction. The concentrated extract can be prepared using a vacuum concentrator or the like. The extract powder can be prepared using the dry powdering process described above.

  As an example of a processed sweet potato stem and leaf product, “sweet potato young leaf powder” manufactured by Toyo Shinyaku Co., Ltd. can be preferably used. This is a sweet potato foliage powder obtained by subjecting sweet potato foliage to heat treatment, followed by drying treatment and powdering treatment.

(3) Glucagon-like peptide-1 (GLP-1) secretion promoter The GLP-1 secretion-promoting component in sweet potato stem leaves (especially “Suiou” sweet potato stem leaves) is contained in (i) processed sweet potato leaves, ii) Sweet potato stem and leaf extract (in particular, a water extract (eg, “hot water extract” in Preparation Example 1 below) and a water-containing ethanol extract (eg, “Water-containing ethanol extract” in Preparation Example 2 below))) And (iii) GLP-1 secretion activity can be maintained even after undergoing gastric digestion (pepsin degradation) after ingestion. Furthermore, the GLP-1 secretion-promoting component is a water-soluble and non-activated charcoal fraction of sweet potato stems (for example, “Fraction 2” described in Preparation Example 5 below) and water-insoluble but soluble in water-containing ethanol. It is contained in a fraction (for example, “Fraction 3” described in Preparation Example 6 below).

  According to the present invention, a processed sweet potato foliage, preferably a sweet potato stover (raw sweet potato foliage or the above-mentioned heat treatment, drying treatment, powdering treatment, pressing treatment, etc.) The extract of sweet potato leaves obtained by extracting the leaves with water or water-containing ethanol can be used as a GLP-1 secretion promoter. As for the sweet potato stem and leaf extract, a water-soluble and non-activated charcoal fraction of sweet potato stem and leaf and a fraction that is water-insoluble but soluble in water-containing ethanol can also be used as a GLP-1 secretion promoter.

  The GLP-1 secretion promoter of the present invention may contain a sweet potato stem and leaf processed product. The amount of sweet potato stem and leaf processed product in the GLP-1 secretion promoter is not particularly limited.

  GLP-1 has effects such as the promotion of insulin secretion, stimulation of the satiety center, suppression of peristaltic movement of the digestive tract by stimulation of food. The GLP-1 secretion promoter of the present invention may be useful for the prevention and improvement of diabetes and obesity. The GLP-1 secretion promoter of the present invention may also be useful for the prevention and treatment of any condition that is ameliorated by increased GLP-1 secretion.

  The compounding amount of the GLP-1 secretion promoter of the present invention depends on the type or dosage form of the product to be formulated, the age, sex, weight or condition of the subject of administration or ingestion, the method of administration or ingestion, timing or time, etc. Can be set appropriately.

  The dose of the GLP-1 secretion promoter of the present invention can be, for example, usually 10 to 2000 mg, preferably 100 to 1000 mg, particularly preferably 300 to 1000 mg per day per adult as an active ingredient. The administration time of the GLP-1 secretion promoter may be any of before meals, between meals and after meals, and may be divided into several times.

  The GLP-1 secretion promoter of the present invention can be prepared as a composition for oral administration or ingestion. The GLP-1 secretion promoter may be formed into a dosage form such as a capsule such as a hard capsule or a soft capsule, a tablet or a pill, or a powder, a granule, a candy, or the like according to the preference of a consumer. . It can also be prepared in liquid dosage forms or forms such as solutions, suspensions, or emulsions.

  The GLP-1 secretion promoter of the present invention can be used as a pharmaceutical, a quasi-drug, a food for specified health use, a dietary supplement, other food or drink, or a mixture thereof.

  The GLP-1 secretion promoter of the present invention or a combination product thereof may be ingested as it is depending on the dosage form, shape, or preference, or dissolved in water, hot water, milk, soy milk, tea, juice or the like. May be.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by these Examples.

  In this example, “sweet potato leaf powder” refers to “Suoi” sweet potato leaf powder (trade name “sweet potato leaf powder” manufactured by Toyo Shinyaku Co., Ltd.).

(Preparation Example 1: Preparation of hot water extract of sweet potato stalks and leaves)
50 g of sweet potato stem and leaf powder was weighed, stirred with a spatula, and suspended in pure water at ordinary temperature (20 ° C.) in a flask while loosening the lump with ultrasonic waves. The flask was placed in a boiling water bath on an oil bath (98 ° C.) and heated for 2 hours with shaking every 15-20 minutes. After removing the rough heat, the flask contents were suction filtered. The filtrate was collected and concentrated under reduced pressure (water temperature 50 ° C.). The obtained concentrate was freeze-dried to obtain a powder (hereinafter also simply referred to as “hot water extract” or “sweet potato leaf hot water extract”).

(Preparation Example 2: Preparation of an aqueous ethanol extract containing sweet potato stalks and leaves)
50 g of sweet potato stem and leaf powder was weighed, stirred with a spatula, and suspended in 60 vol% aqueous ethanol at room temperature (20 ° C.) in a flask while sonicating the lump. While stirring the powder with a stirrer, it was sufficiently immersed at room temperature (20 ° C.) (not shaded). The flask contents were suction filtered, and the filtrate was collected, concentrated under reduced pressure (water temperature 40 ° C.), and then freeze-dried to obtain a powder (hereinafter simply referred to as “hydrous ethanol extract” or “sweet potato leaf hydrous ethanol extract”. ”).

(Preparation Example 3: Preparation of pepsin degradation product from sweet potato stover)
10 g of sweet potato stem and leaf powder was suspended in a phosphate buffer having a pH of 1.85, and pepsin (manufactured by Sigma) was added at a ratio of 0.5% by mass to this dry powder. This mixed solution was kept at 37 ° C. for 10 minutes to carry out pepsin treatment. The enzyme reaction was stopped by treating in a boiling bath for 20 minutes, neutralized with calcium hydroxide, and the supernatant after centrifugation was freeze-dried to obtain a powder (hereinafter simply referred to as “pepsin degradation product (10 minutes)”. "Or" sweet potato stem and leaf pepsin degradation product (10 minutes) ").

(Preparation Example 4: Preparation of sugarcane stalk and leaf pepsin degradation product)
Except that the pepsin treatment time was set to 60 minutes, a powder of a sweet potato stem-and-leaf pepsin degradation product was obtained in the same manner as in Preparation Example 3 (hereinafter simply referred to as “pepsin degradation product (60 minutes)” or “sweet potato stem-and-leaf pepsin degradation product ( 60 minutes) ").

(Example 1: GLP-1 secretion test 1)
The GLP-1 secretion test was performed according to the following procedure. First, a GLP-1-producing cell line GLUTag (provided by Dr. Daniel J. Drucker, Mount Sinai Hospital, Samuel Lunenfeld Research Institute Banting and Best Diabetes Centre, University of Toronto), 10% in a 48-well plate. The cells were cultured in Dulbecco's modified Eagle's medium containing fetal bovine serum (FBS) in the presence of 37 ° C. and 5% CO ₂ until they became subconfluent for 2-3 days. Subsequently, the culture medium is removed from the well, and Hepes buffer (140 mM NaCl, 4.5 mM KCl, 20 mM Hepes, 1.2 mM CaCl ₂ , 1.2 mM MgCl ₂ , 10 mM D-glucose, 0.1% bovine serum albumin (BSA), pH 7.4) After washing the cells in the wells, 80 μL of the test substance solution dissolved in the same Hepes buffer was added to each well and incubated at 37 ° C. for 60 minutes. The supernatant was collected and centrifuged at 800 × g for 5 minutes at 4 ° C. to precipitate the cells, and 70 μL of the supernatant was collected and stored frozen. The cryopreserved supernatant was appropriately thawed, and the concentration of GLP-1 in the supernatant was quantified using a commercially available Enzyme immuno assay kit (manufactured by Yauchihara Laboratory). The GLP-1 concentration (nM) in the supernatant was defined as the amount of GLP-1 secretion from the GLP-1-producing cell line GLUTag.

The following were used as test substances (both 10 mg / mL):
ZeinH (Papain hydrolyzate of maize indigestible protein Zein: corn-derived zein (manufactured by Tokyo Chemical Industry Co., Ltd.) is suspended in demineralized water and adjusted to pH 7, and papain (manufactured by Asahi Breweries) is used as a substrate. Added at a ratio of 0.5% by mass, treated at 55 ° C. for 60 minutes, inactivated papain by boiling, and freeze-dried centrifugal supernatant; used as a positive control);
Sweet potato stem powder;
Hot water extract of Preparation Example 1;
Hydrous ethanol extract of Preparation Example 2;
Sweet potato stover pepsin degradation product of Preparation Example 3 (10 minutes);
The sweet potato stem-and-leaf pepsin degradation product of Preparation Example 4 (60 minutes).

  The results are shown in FIG. FIG. 1 shows the amount of GLP-1 secretion of GLP-1 producing cell line GLUTag derived from the large intestine of mice by each treatment of sweet potato stem powder, sweet potato stem hot water extract, sweet potato stem hydrous ethanol extract, and sweet potato stem fever pepsin degradation product Is a diagram represented by a bar graph. The results of untreated blank as a negative control and ZeinH treatment as a positive control are shown together. The vertical axis represents GLP-1 secretion in nM units, and the horizontal axis, in order from the left, “blank” is the negative control group (untreated group), “ZeinH” is the positive control group (ZeinH added group) ) As a result, “sweet potato stem powder” is the result of the sweet potato stem powder processing section, “hot water extract” is the result of the hot water extract processing section, “hydrous ethanol extract” is the result of the aqueous ethanol extract processing section, “Pepsin degradation product (10 minutes)” shows the result of the pepsin degradation product (10 minutes) treatment group, and “Pepsin degradation product (60 minutes)” shows the result of the pepsin degradation product (60 minutes) treatment group. The resulting value is expressed as mean value + standard error (n = 3-4). In the figure, a, b, c, and d indicate that there is a significant difference between the treatment groups by displaying symbols having different alphabets in Duncan's multigroup significance test (P <0.05).

  As shown in FIG. 1, GLP-1 secretion activity equivalent to that of the positive control ZeinH was observed for the sweet potato leaf powder. Both hot water extract and hydrous ethanol extract showed significantly higher GLP-1 secretion activity than ZeinH.

  For the pepsin degradation product, GLP-1 secretion activity equivalent to that of the positive control ZeinH was observed in both the 10-minute treatment and the 60-minute treatment. The effect of pepsin treatment time was not observed on GLP-1 secretion activity. Therefore, it was found that the GLP-1 secretion-promoting component in the sweet potato stem and leaves of “Suio” can maintain the GLP-1 secretion activity even after undergoing gastric digestion after ingestion.

  From the above, the GLP-1 secretion-promoting component in the sweet potato stem and leaf of “Suoi” is contained in (i) the sweet potato stem and leaf powder, (ii) in particular in the hot water extract and the aqueous ethanol extract, and (Iii) It was found that GLP-1 secretion activity can be maintained even after digestion in the stomach after oral ingestion.

(Preparation Example 5: Fractionation of sweet potato stalks and leaves water-soluble fraction by activated carbon adsorption treatment)
100 g of sweet potato stem and leaf powder was weighed, and the powder was stirred with a spatula and suspended in pure water at ordinary temperature (20 ° C.) in a flask while loosening the lump with ultrasonic waves. While stirring the powder with a stirrer, it was sufficiently immersed at room temperature (20 ° C.). Thereafter, the supernatant was collected by centrifugation and suction filtered to obtain a filtrate and a residue. The filtrate was concentrated under reduced pressure, and the resulting concentrate was lyophilized to obtain a powdery “water-soluble fraction”. This “water-soluble fraction” was dissolved in water and then subjected to activated carbon column chromatography to obtain the following two fractions. One is a fraction obtained by desorbing and eluting activated charcoal adsorbate using methanol and acetone, and this is designated as fraction 1 ("water-soluble activated carbon adsorbed fraction"). The other is a fraction passed through without being adsorbed on activated carbon, and this is designated as fraction 2 ("water-soluble-activated carbon non-adsorbed fraction").

(Preparation Example 6: Fractionation of sweet potato stem water insoluble fraction with water-containing ethanol)
The residue after suction filtration obtained in Preparation Example 5 was freeze-dried to obtain a powdery “water-insoluble fraction”. 60% by volume of water-containing ethanol was added to this “water-insoluble fraction” to obtain the following two fractions. One is a filtrate obtained after suspending and immersing the “water-insoluble fraction” in 60% by volume aqueous ethanol, and this is designated as fraction 3 (“water-insoluble-60% by volume ethanol-soluble fraction”). ). The other is a residue obtained after suspending and immersing the “water-insoluble fraction” in 60% by volume aqueous ethanol, and this is designated as fraction 4 (“water-insoluble-60% by volume ethanol-insoluble fraction”). ").

(Example 2: GLP-1 secretion test 2)
Example except that ZeinH (used as a positive control), hot water extract of Preparation Example 1, fractions 1 and 2 of Preparation Example 5, and fractions 3 and 4 of Preparation Example 6 were used as test substances. The GLP-1 secretion test was conducted in the same manner as in 1. The test substances were prepared so as to be equivalent to 10 mg / mL for hot water extract and ZeinH, and 10 mg / mL for hot water extract for fractions 1 to 4.

  The results are shown in FIG. FIG. 2 shows a sweet potato stalk-and-leaves hot water extract, fraction 1 (water-soluble-activated carbon-adsorbed fraction), fraction 2 (water-soluble-activated carbon non-adsorbed fraction), and fraction 3 (water-insoluble-60% ethanol-dissolved fraction). (Fraction fraction) and GLP-1 secretion amount of GLP-1-producing cell line GLUTag derived from the mouse large intestine by each treatment of fraction (4) and fraction 4 (water-insoluble-60 volume% ethanol-insoluble fraction) in a bar graph is there. The results of untreated blank as a negative control and ZeinH treatment as a positive control are shown together. The vertical axis represents GLP-1 secretion in nM units, and the horizontal axis, in order from the left, “blank” is the negative control group (untreated group), “ZeinH” is the positive control group (ZeinH added group) As a result, “hot water extract” is the result of the sweet potato stalks and leaves hot water extract treatment group of Preparation Example 1, “fraction 1” is the result of the fraction 1 (water-soluble activated carbon adsorption fraction) treatment group, “ "Fraction 2" is the result of the fraction 2 (water-soluble-active carbon non-adsorbed fraction) treatment group, "Fraction 3" is the result of the fraction 3 (water-insoluble-60% ethanol-dissolved fraction) treatment group, and “Fraction 4” shows the result of the treatment with fraction 4 (water-insoluble-60% by volume ethanol-insoluble fraction). The resulting value is expressed as mean value + standard error (n = 4). In the figure, a, b, and c indicate that there is a significant difference between the treatment groups by displaying symbols having different alphabets in Duncan's multigroup significance test (P <0.05).

  As shown in FIG. 2, both fraction 2 (water-soluble-active carbon non-adsorbed fraction) and fraction 3 (water-insoluble-60% ethanol-dissolved fraction) were both significantly higher than ZeinH and extracted with hot water. GLP-1 secretion activity comparable to that of the product was observed.

  The processed sweet potato foliage can be useful for the prevention and improvement of diabetes and obesity based on its GLP-1 secretion promoting action. The GLP-1 secretion promoter containing such processed sweet potato stem and leaves can be widely used for pharmaceuticals and foods and drinks.

Claims (3)

  A glucagon-like peptide-1 secretion promoter containing a processed sweet potato stem and leaf.   The glucagon-like peptide-1 secretion promoter of Claim 1 whose said sweet potato foliage processed material is a sweet potato foliage extract obtained by extracting a sweet potato foliage with water or water-containing ethanol.   The glucagon-like peptide-1 secretion promoter of Claim 2 whose said water-containing ethanol is water-containing ethanol whose ethanol content is less than 80 volume%.

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