JP4798607B2 - Angiotensin converting enzyme inhibitor and food and drink using the same - Google Patents

Description

  The present invention relates to an ACE inhibitor having an action of inhibiting the action of angiotensin converting enzyme (hereinafter referred to as ACE) involved in the production of angiotensin 2 having an action of contracting blood vessels (exactly Roman numerals, the same shall apply hereinafter) and It relates to food and drink using it.

In recent years, a large number of foods having an action of suppressing an increase in blood pressure have been developed and marketed. In particular, a food that inhibits the action of ACE involved in the production of angiotensin 2 having the effect of contracting blood vessels is effective in lowering blood pressure over a long period of time.
Most of the ACE inhibitors are peptides such as lactotripeptides and koji polypeptides, which have strong bitterness and odor, and when applied to actual foods, The prescription is limited, such as the need for sweetening and flavoring to mask bitterness and odor.
In addition, ACE inhibitors other than peptides include chlorogenic acid, caffeic acid, etc., but these also have a bitter taste peculiar to peptides, but have an exciting bitter taste peculiar to low molecular weight polyphenols and are satisfactory in terms of taste. The prescription to go is restricted.

  In addition to the above, as an ACE inhibitor, fruit polyphenols obtained from immature fruits that are discarded by picking fruits of rosaceae (especially apples, pears, peaches, etc.), for example, at the time of beer production. Roots or root extracts of grasses such as wheat roots to be discarded (see, for example, Patent Document 2), seeds of legumes such as soybeans, red beans, black beans, leguminous plant seed water extract and crude It is known that an extract (see, for example, Patent Document 3) is effective.

However, since both Patent Documents 1 and 2 frequently use agricultural chemicals for cultivation, there is a risk that the agricultural chemicals remain in the plant, and there is a concern about the influence on the human body. If low agricultural chemicals and organic cultivation are used, the production scale is small and the merit of using waste is small.
Moreover, since the raw material of patent document 3 is a raw material which can be normally eaten, or a raw material which can be used as a food raw material if it is cultivated as it is, in order to obtain an ACE inhibitor, it is necessary to cultivate separately. Moreover, when these food raw materials are used, an unnecessary site | part becomes a waste and there exists a problem that it is bad for an environment.

  On the other hand, the present inventors have found out that it has an antioxidant action and an α-glucosidase inhibitory action for the use of chestnut demon skin and astringent skin, which are wastes generated during the production process of sweet chestnuts, (For example, refer to Patent Documents 4 and 5). However, at the time of these applications, it was not found that the chestnut skin extract has an action of inhibiting ACE.

Japanese Patent Laid-Open No. 2002-47196 JP 2004-51519 A JP-A-4-2611122 JP 2004-189956 A Japanese Patent Application No. 2004-179010

The present invention has been made in view of such circumstances, the purpose of which can be obtained from waste after primary use, has a high effect at a low concentration, good flavor, It is an object of the present invention to provide a novel angiotensin converting enzyme inhibitor which can be easily taken continuously, and can be applied to various dosage forms, particularly when it is water-soluble, and a food and drink using the same.

  The above object of the present invention is achieved by an angiotensin converting enzyme inhibitor characterized by containing a chestnut skin extract.

Preferably, the chestnut skin extract is a calcined chestnut skin extract. More preferably, the chestnut skin extract is an extract extracted with an extraction solvent containing a hydrophilic solvent. More preferably, the chestnut skin extract contains chestnut-derived tannins. Furthermore, it is desirable that the chestnut skin extract contains proanthocyanidins derived from chestnut skin.
Moreover, the said angiotensin converting enzyme inhibitor may be contained in food / beverage products, and may display on the food / beverage products the effect of preventing and improving hypertension.

That is, in general, hypertension is divided into essential hypertension and secondary hypertension. Among these, the present inventors have a genetic predisposition and an unfavorable lifestyle of daily life (excessive salt intake, stress). Focusing on essential hypertension other than the cause of hypertension other than exercise, lack of exercise, alcohol, obesity, etc.) Even within the already known symptomatic mechanism, if the production of angiotensin 2 can be significantly inhibited, blood pressure can be reduced I thought that I could do it, and studied it earnestly.
Therefore, focusing on proanthocyanidins, which are conventionally known to be effective in suppressing blood pressure rise, it is possible to recycle waste after primary use, etc., and has a strong blood pressure rise inhibitory effect, and even if added to food, food We searched for various food and beverage ingredients that have little influence on the original flavor.
As a result, it was surprisingly found for the first time that chestnut skin that has been abundantly discarded as waste during the production of various chestnut products, particularly extracts using demon skin and astringent skin, have an ACE inhibitory action, The present invention has been reached.

According to the present invention, there is no flavor in the flavor and it is easier to continuously ingest than the peptides that are conventional ACE inhibitors.
Further, since a strong ACE inhibitory action is obtained, it is not necessary to use other blood pressure lowering agents in combination, and flavor deterioration caused by other blood pressure lowering agents can be prevented, and a variety of flavor development can be achieved.
Furthermore, since it does not limit the form of the ACE inhibitor obtained in the present invention, the form of food and drink using the same, etc., it can be taken with meals and is highly versatile.
In addition, when the ACE inhibitor of the present invention is particularly water-soluble, it can be easily mixed and dissolved in foods and drinks using the same, and has high applicability to foods and drinks.
In addition, since chestnut demon skin and astringent skin that has been abundantly discarded when manufacturing chestnut confectionery such as sweet chestnuts, chestnut honey boiled, and maroon rasse can be used effectively, there is no need to cultivate the raw material in particular, and it is inexpensive and safe. Stable supply of raw materials is possible, and it helps to reduce the amount of waste discharged, taking into consideration the impact on the global environment.
Furthermore, by using chestnut skin, an extract having an ACE inhibitory action can be obtained only by the extraction step without providing a complicated step, so that an ACE inhibitor can be obtained easily and efficiently in a short time. it can.

  The present invention will be described in detail.

First, the ACE inhibitor of the present invention is an amino acid 1 produced by the action of renal protease renin on angiotensinogen, a glycoprotein having a molecular weight of 57,000 in the bloodstream.
It is an inhibitor of an enzyme that acts on the decapeptide angiotensin 1 (exactly Roman numerals, the same shall apply hereinafter) and catalyzes a reaction to produce angiotensin 2 which is a pressor hormone.
The angiotensin 2 directly contracts the peripheral capillaries to stimulate the sympathetic nerves and adrenal glands and promotes the release of catecholamines, thereby causing an increase in blood pressure.

The ACE inhibitor of the present invention contains chestnut skin extract.
The varieties and sizes of chestnuts that are raw materials of the present invention are not particularly limited, and may be appropriately selected from those generally used. Examples of chestnut varieties include Japanese chestnut, European chestnut, Chinese chestnut, and American chestnut.

The chestnuts used in the ACE inhibitor of the present invention are chestnut astringents from which the flesh portion has been removed and nuts from the outermost skins, and these are appropriately selected either alone or in combination. Can be used.
The chestnut skin may be a waste after the primary use or may be peeled from the chestnut with the flesh, and is not particularly limited, but it is cheaper to use the waste after the primary use. It is suitable in that it can provide a safe and stable raw material supply and can reduce the amount of waste discharged.

The chestnuts may be raw or may be used after being subjected to various treatments such as baking, heating, freezing, drying, boiling, etc. singly or in combination.
In particular, the chestnut that has undergone baking treatment does not impair the original flavor of the food even when added in an effective amount, and exhibits an advantageous effect, and when added in a large amount, imparts a fragrant and delicious flavor. Therefore, it is preferably used for roasting foods and drinks such as coffee and barley tea, and more preferable in terms of imparting a preferable amber color tone.
When using the chestnut that has been subjected to the baking treatment, for example, in the case of raw chestnuts for peeling chestnut, it can be about 250 to 400 ° C. for about 5 to 10 minutes due to hot air roast, etc. It is not limited to the said conditions.

  The chestnut skin extract of this invention points out what was extracted from the said chestnut skin by the appropriate extraction method. Preferably, tannin is extracted from the viewpoint of ACE inhibitory activity.

The tannin is a general term for plant-derived compounds having many phenolic hydroxyl groups and licking animal skin, and is roughly classified into hydrolyzed tannin and condensed tannin.
Hydrolyzed tannin generally has a galloyl group, a hexahydroxydiphenoyl group, and an oxidant thereof as a polyphenol moiety in the molecule, and has a structure in which these are ester-linked to a sugar or a cyclic polyalcohol in the molecule.
On the other hand, condensed tannin is a dimer or higher polymer in which flavins such as catechin are bonded to each other by C—C bonds at the C ₄ -C ₈ position or C ₄ -C ₆ position between molecules. It is formed and is different in classification from monomeric flavonoids. Among condensed tannins, those that produce anthocyanidins by cleavage of the C—C bond are called proanthocyanidins.

  As described above, the chestnut skin extract according to the present invention preferably contains tannin, and among the tannins, particularly condensed tannin, more preferably proanthocyanidins, It is preferable in terms of ACE inhibitory activity.

The ACE inhibitor in the present invention contains the chestnut skin extract as an active ingredient. An active ingredient shows that this extract is included to such an extent that the target function is exhibited. Specifically, the chestnut skin extract preferably contains 50% by weight or more, more preferably 80% by weight or more of the chestnut skin extract, more preferably the whole ACE inhibitor contains the chestnut skin extract. It is desirable that the ACE inhibitory activity can be sufficiently obtained.

The ACE inhibitor of the present invention may contain an auxiliary material appropriately selected within a range not impairing the object of the present invention. For example, sugar sweeteners (monosaccharides such as fructose, glucose, tagatose and arabinose, oligosaccharides such as lactose, oligosaccharides, maltose and trehalose, powdered starch syrup, dextrin, sugar alcohol, etc.) (Sucralose, acesulfame K, stevia, etc.), polysaccharides such as starch, fats and oils, dairy products, stabilizers, emulsifiers, fragrances, pigments, acidulants, flavoring ingredients (eggs, coffee, teas, cocoa, fruit pulp, Yogurt, alcoholic beverages, etc.), protein, dietary fiber, vitamins, minerals, γ-aminobutyric acid, casein decapeptide, mulberry leaf extract, guava tea extract, catechin, raspberry ketone, low molecular weight alginic acid, ginkgo biloba extract, pine bark Extracts, chitosan, hyaluronic acid, methylsulfonylmethane and the like can be mentioned.
Among these, it is preferable to use known γ-aminobutyric acid and casein decapeptide as blood pressure lowering agents in a range that does not adversely affect the flavor, since the blood pressure increase suppression and blood pressure lowering effects are synergistically enhanced.
The above auxiliary materials may be used alone or in combination.

  The form of the ACE inhibitor of the present invention is not particularly limited, and examples thereof include various forms such as liquid, powder, granule, and paste. Among these, powder or granule is preferable in that the ACE inhibitory activity effect is stably maintained for a long time.

Next, the ACE inhibitor of this invention is manufactured as follows, for example using the chestnut skin which is the waste after primary utilization.
That is, first, chestnut skin, which is waste after primary use, is prepared. At this time, finely pulverizing chestnut skin is preferable in that the extract can be extracted efficiently. In the stage of preparing the ACE inhibitor of the present invention, when chestnut skin is baked, either the baking process or the pulverization process may be performed first, but it is more efficient to perform the calcination after performing the baking process. From the viewpoint of sex. Moreover, you may make it remove a hydrophilic fraction previously by giving the process of wash | cleaning a chestnut skin with water, immersing in water, and filtering.

On the other hand, an extraction solvent for extracting chestnut skin is prepared.
Examples of the extraction solvent include hydrophilic solvents, polyhydric alcohols, supercritical carbon dioxide, and the like. These may be used alone or in combination, but at least the hydrophilic solvent contains extraction efficiency and versatility for food and drink. And it is suitable at the point which obtains the water-soluble ACE inhibitor excellent in processability.
Examples of the hydrophilic solvent include water, ethanol, methanol, propanol, isopropanol, acetone, butanol, acetonitrile, ethyl acetate, and tetrahydrofuran.
Examples of the polyhydric alcohol include glycerin and polyglycerin.
These may be an aqueous solution or a dispersion mixed alone or in combination.
Among these, it is preferable to use ethanol, more preferably 20 to 80% by weight ethanol aqueous solution, because it is excellent in ACE inhibitory activity and can extract a water-soluble ACE inhibitor efficiently.

Next, the chestnut skin extract is extracted using the chestnut skin prepared as described above and the extraction solvent.
Examples of the extraction method include reflux operation and room temperature immersion. Among these, extraction by refluxing is preferable from the viewpoint of efficiently obtaining an extract excellent in ACE inhibitory activity in a short time.
When extracting by refluxing using ethanol, if the temperature of the extraction solvent at the time of extraction by bringing the chestnut skin into contact with the extraction solvent is set to 50 ° C. or higher, an extract having further excellent ACE inhibitory activity can be efficiently obtained. It is preferable in terms of obtaining.

  The extract obtained as described above may be appropriately combined with a purification treatment using a column or the like as necessary. Preferably, a combination in which 30% by weight or more of proanthocyanidins is extracted in terms of the solid content of the extract is suitable in terms of obtaining an extract excellent in ACE inhibitory activity.

  Next, the ACE inhibitor of the present invention can be obtained by adding an auxiliary raw material or the like to the above extract as necessary and appropriately making it into a desired form by a conventional method such as lyophilization, vacuum concentration, spray drying or the like. In addition, dextrin or the like may be used as a binder when forming into powder or granules.

  The ACE inhibitor thus obtained can be applied not only to various foods and drinks but also to pharmaceuticals and general industrial products. Especially, when it uses for food-drinks, it can eat easily and deliciously and it is suitable at the point which can obtain an ACE inhibitory action efficiently and easily. Moreover, when the said ACE inhibitor is water-soluble, it does not ask | require the dosage form of the food / beverage products, pharmaceuticals, and general industrial products which are applied especially.

The food and drink is not particularly limited as long as it can contain the above-mentioned ACE inhibitor. For example, confectionery (chewing gum, candy, tablet, chocolate, jelly, etc.), frozen confectionery, noodles, etc. Starch foods, powdered foods, beverages (soups, coffee, teas, juices, cocoa, alcoholic beverages, jelly drinks, etc.), bakery foods (bread, biscuits, etc.), fat foods (margarine, shortening) , Fat spread, etc.) and high salt content foods (miso, soy sauce, pickles, boiled, salted, ham, etc.).
In addition, what is necessary is just to select suitably the addition time of the said ACE inhibitor to the food / beverage products of this invention in the step of a manufacturing process according to the characteristic and the objective of each food / beverage product.

  The content of the ACE inhibitor in the food or drink varies depending on the type or purpose of each food or drink, but in terms of solid content of chestnut skin extract, in the total weight of the food or drink, preferably 0.001% by weight or more, More preferably, it is 0.01% by weight or more from the viewpoint of ACE inhibitory activity.

  In addition to the ACE inhibitor, the food and drink of the present invention may contain the auxiliary material selected as appropriate within a range that does not impair the original purpose.

  Next, as an example of the food and drink of the present invention, a hard candy is manufactured as follows, for example. That is, first, an ACE inhibitor is prepared as described above. On the other hand, candy raw materials such as granulated sugar and syrup are boiled and cooled to prepare candy dough. And when mixing candy raw materials other than the above candy main raw materials (for example, fragrances, coloring agents, etc.) into the candy dough, after adding and mixing the ACE inhibitor and auxiliary materials such as fragrances if necessary, further cooling, If molded appropriately, the ACE inhibitor-containing hard candy of the present invention can be obtained.

  Not only the ACE inhibitor-containing hard candy thus obtained, but also the ACE inhibitor-containing food or drink of the present invention may be provided with an indication that hypertension is improved. Examples of indications are "For people with high blood pressure", "For stable blood pressure", "For those with higher blood pressure", "For those who are concerned about blood pressure", "For those who are concerned about blood pressure" And “for those who are managing blood pressure”.

  Hereinafter, the present invention will be illustrated using examples.

≪Preparation of ACE inhibitor≫
<Example 1> (baked chestnut unpurified or unfractionated)
Chestnuts from Hebei Province, China, were baked with hot air roast at 300 ° C for 7 minutes, peeled chestnuts (demon skins and astringent skins), and then only the peeled chestnuts were used as confectionery raw materials to collect chestnuts.
The chestnut skin collected as described above was pulverized with a coffee mill. This ground chestnut skin product was put into a flask, 50% by weight aqueous ethanol solution was subsequently poured, and heated in a water bath at 70 ° C. for 4 hours. At this time, in order to prevent evaporation of ethanol, a Liebig condenser was provided at the top of the flask, and a reflux operation was performed by flowing cold water through the condenser. The resulting extract was filtered and separated into filtrate and residue. The filtrate was concentrated and freeze-dried to obtain chestnut skin extract powder.
The total tannin content of the chestnut skin extract powder thus obtained was 47% by weight based on the total weight of the powder. The total proanthocyanidin content was 44% by weight based on the total weight of the powder (calculated by the vanillin hydrochloric acid method).
The total tannin content is calculated by adding the vanillin hydrochloric acid method, the method of Wilson et al. ((1990) J. Agric. Food. Chem 38, 1678-1683), the method of Inoue et al. (1988) Analytical Biochemistry 169, 363-369). did.

<Example 2> (Calcined chestnut filtrate 20% ethanol aqueous solution elution fraction)
After concentrating the filtrate obtained by the same method as in Example 1, the column was filled with a synthetic adsorbent (manufactured by Mitsubishi Chemical Corporation, HP-20), and the concentrated filtrate was poured and adsorbed. Thereafter, the synthetic adsorbent was washed with distilled water to wash out the hydrophilic fraction, and the polymer fraction was eluted from the synthetic adsorbent with a 20 wt% aqueous ethanol solution. The eluate fraction was concentrated and freeze-dried to obtain chestnut skin extract powder.
The total tannin content of the chestnut skin extract powder thus obtained was 58% by weight based on the total weight of the powder (measured in the same manner as in Example 1). The total proanthocyanidin content was 55% by weight (measured in the same manner as in Example 1) in the total weight of the powder.

<Example 3> (Baking chestnut filtrate 40% ethanol aqueous solution elution fraction)
The polymer fraction was eluted from the synthetic adsorbent with a 20% by volume ethanol aqueous solution to obtain the polymer fraction of Example 2. Subsequently, the polymer fraction was similarly used in Example 3 with a 40% by weight ethanol aqueous solution. Minutes were eluted. And the elution fraction obtained with this 40 weight% ethanol aqueous solution was concentrated and freeze-dried, and chestnut skin extract powder was obtained.
The total tannin content thus obtained was 66% by weight based on the total weight of the powder (measured in the same manner as in Example 1). The total proanthocyanidin content was 63% by weight (measured in the same manner as in Example 1) in the total weight of the powder.

<Example 4> (baked chestnut residue polymer fraction)
Example 1 Before putting the chestnut skin crushed water in a 50 wt% aqueous ethanol solution into the flask, put the crushed chestnut skin and distilled water (20 ° C) in the flask and let stand at room temperature overnight, then remove the water. A chestnut skin extract powder was obtained in the same manner as in 1.
The total tannin content of the chestnut skin extract powder thus obtained was 54% by weight based on the total weight of the powder (measured in the same manner as in Example 1). The total proanthocyanidin content was 51% by weight based on the total weight of the powder (measured in the same manner as in Example 1).

<Example 5> (raw chestnut skin unpurified or unfractionated)
A raw chestnut skin extract powder was obtained in the same manner as in Example 1 except that the chestnuts from Hebei Province, China were peeled raw and the chestnuts (devil skin and astringent skin) were peeled off and the chestnuts were crushed with a coffee mill. It was.
The total tannin content of the raw chestnut skin extract powder thus obtained was 68% by weight based on the total weight of the powder (measured in the same manner as in Example 1). The total proanthocyanidin content was 65% by weight based on the total weight of the powder (measured in the same manner as in Example 1).

≪Measurement of ACE inhibition rate≫
About the chestnut skin extract powder (water-soluble) of Examples 1 to 5 prepared as described above, the ACE inhibition rate was measured by the following method.
When ACE (enzyme) decomposes N-Hippuryl-His-Leu tetrahydrate (an artificial substrate having a binding moiety similar to angiotensin 1, an angiotensin 1 substitute), the chestnut skin extract powders of Examples 1 to 5 were used. In addition, the extent to which decomposition was inhibited was measured using an absorptiometer.
(1) Preparation of substrate solution
N-Hippuryl-His-Leu tetrahydrate was dissolved in a borate buffer solution of 125 mM · pH 3.8 so as to be 5.83 mM, and the volume was made up to 5 ml.
(2) Sample solution preparation
10 mg each of chestnut skin extract powders of Examples 1 to 5 was dissolved in a boric acid buffer solution of 125 mM · pH 3.8 and made up to 10 ml.
(3) Enzyme solution preparation
The Angiotensin Converting Enzyme was adjusted to 0.008 U per 50 μl with a 125 mM · pH 3.8 borate buffer solution.
(4) Measurement procedure In accordance with Table 1, the substrate solution and each sample solution in which the chestnut skin extract powders of Examples 1 to 5 were dissolved or only a borate buffer solution were added and mixed, and preheated at 37 ° C. for 5 minutes. did. 2. To the above 1, the enzyme solution of Table 1 was added and reacted at 37 ° C. for 30 minutes.
3. 50 μl of 1N hydrochloric acid was added to 2 above to stop the enzyme reaction.
4. 1500 μl of ethyl acetate was added and mixed for 10 seconds with a test tube mixer to extract the reaction product.
5. Centrifugation was performed at 3,500 rpm for 2 minutes, and 1000 μl of the supernatant was transferred to a 50 ml beaker.
6). Heated on a hot plate to dry the ethyl acetate.
7). Redissolved with 1000 μl of distilled water and left for 15 minutes.
8). The solution obtained in 7 above was measured (228 nm).

(5) Calculation of inhibition rate The absorbance of each chestnut skin extract powder obtained from the above was substituted into the following formula to determine the inhibition rate.
Inhibition rate (%) = (A−B) ÷ A × 100
A = Absorbance (control)-Absorbance (base)
B = Absorbance (sample)-Absorbance (blank)
The above-mentioned absorbances A and B represent the absorbance of only the decomposition products of the substrate.
The results of the inhibition rate are shown in Table 2.

  From the results in Table 2, it can be seen that Examples 1 to 5 show almost the same high ACE inhibitory activity. In particular, Example 4 shows a high inhibition rate and is particularly suitable. In addition, the ACE inhibitor of Example 4 is a method that does not use column purification and exhibits an inhibition rate equal to or higher than that of column purification. Therefore, the production process is simpler than column purification, and the ACE inhibitor is inexpensively used. I was able to manufacture it.

<Comparative Example 1>
Next, the inhibition rate of a 0.1% by weight chlorogenic acid aqueous solution (Comparative Example 1), which is conventionally known as an ACE inhibitor, was measured.
And the inhibition rate of the said chlorogenic acid aqueous solution and the inhibition rate of the 0.1 weight% concentration aqueous solution of the chestnut skin extract of the said Examples 1-5 were compared.

As a result, since the inhibition rate of the chlorogenic acid aqueous solution was 31%, the inhibition rate was slightly higher than that of Examples 1 and 2, which was almost the same as that of Examples 3 and 5. No. 4 had a higher inhibition rate.

<Examples 6 to 10>
≪Preparation of beverage≫
According to a conventional method, PET-containing barley tea was produced. The barley tea was divided and 0.05% by weight of each chestnut skin extract powder of Examples 1 to 5 was added to prepare barley tea containing the chestnut skin extract powder of each Example (Example 1). Chestnut extract powder-containing barley tea in Example 6, Example 2 product-containing barley tea in Example 7, Example 3 product-containing barley tea in Example 8, Example 4 product-containing barley tea in Example 9 and Example 5 Barley tea is designated as Example 10). As a control, a chestnut skin extract powder was not added.

<Comparative example 2>
As Comparative Example 2, barley tea with PET was produced according to a conventional method. To this, 0.05% by weight of chlorogenic acid was added.

As a result of drinking 200 ml of the barley tea beverages of Examples 6 to 10, Control and Comparative Example 2 after 20 meals per week for 20 expert panelists, the products of Examples 6 to 9 are almost amber with respect to the control. Rather, it became a deep amber color tone, and it was a fragrant and fragrant barley tea drink that was easy to use continuously. Although the product of Example 10 was inferior in flavor and color tone as compared with Examples 6 to 9, it could be used continuously. The chestnut skin extract powder was excellent in solubility in barley tea, dispersed uniformly, and even when placed in a transparent PET bottle, it did not precipitate and was good in appearance.
On the other hand, the product of Comparative Example 2 had a strong bitterness and a delicious taste and was unsuitable for daily use.

  From the above results, the chestnut skin extract of the present invention has ACE inhibitory activity and good flavor and solubility, and even when added to foods and drinks, it did not adversely affect. On the other hand, although chlorogenic acid has some ACE inhibitory activity, it can be understood that it has a bad taste and is difficult to take continuously.

Claims (4)

It is characterized by containing an extract extracted with an aqueous ethanol solution of calcined chestnut from which the hydrophilic fraction has been removed in advance by washing it with water or immersing it in water, followed by filtration. Angiotensin converting enzyme inhibitor. Extract of firing chestnut skin is, angiotensin converting enzyme inhibitors according to claim 1 Symbol placement containing tannin from chestnut skin. The angiotensin converting enzyme inhibitor according to claim 1 or 2 , wherein the extract of calcined chestnut skin contains proanthocyanidins derived from chestnut skin. The manufacturing method of the angiotensin converting enzyme inhibitor containing the extract of baking chestnut skin characterized by including the following processes.
- a step-the firing chestnut skin of firing the chestnut skin, extracting the firing chestnut skin which processes and the above filtration process for filtering off process after immersion in either water or washed with water at an aqueous ethanol solution process