Dipeptidyl peptidase-iv inhibitors

Abstract

An object of the present invention is to find a novel extract derived from a natural product having a dipeptidyl peptidase-IV inhibitory activity, and to provide a dipeptidyl peptidase-IV inhibitor, an agent for suppressing an increase in blood glucose level, and an antidiabetic agent.SOLUTION: The black ginger extract and the Cullen corylifolium extract have a dipeptidylpeptidase-IV inhibitory activity, and can be used as dipeptidylpeptidase-IV inhibitors, and hypoglycemic agents and antidiabetic agents containing the same.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dipeptidyl peptidase-IV inhibitor, and also to an agent for suppressing blood glucose elevation, an antidiabetic agent, and the like, containing the dipeptidyl peptidase-IV inhibitor. [Background technology]

[0002] In recent years, gastrointestinal hormones called incretins have been attracting attention in the treatment of type 2 diabetes. Incretins are secreted from the gastrointestinal tract following meal intake and act on pancreatic β cells to promote insulin secretion. They also inhibit the secretion of glucagon, which increases blood glucose levels, and protect and promote the proliferation of pancreatic β cells. Although incretins play an important role in lowering blood glucose levels, they are rapidly degraded and inactivated by dipeptidyl peptidase-IV (DPP-IV) in the blood. Therefore, the use of DPP-IV inhibitors has been considered a promising therapeutic strategy for type 2 diabetes. Therefore, various compounds with DPP-IV inhibitory activity have been identified.

[0003] For example, Patent Document 1 describes that a fluoropyrrolidone derivative with a specific structure can be used as a DPP-IV inhibitor to inhibit serine proteases such as DPP-IV. Patent Document 2 describes that a proline derivative with a specific structure can be used as a DPP-IV inhibitor. However, the DPP-IV inhibitors reported in Patent Documents 1 and 2 are chemically synthesized products that have never been consumed, and have the disadvantage that they cannot be used routinely as foods or the like.

[0004] On the other hand, several DPP-IV inhibitors using naturally occurring ingredients have been reported. For example, Patent Document 3 describes that ambrosia extract, sesame peptide, lemon balm extract, ginkgo extract, yacon extract, and linden extract have DPP-IV inhibitory activity. As described above, several DPP-IV inhibitors using naturally occurring ingredients have been reported, but from the viewpoint of increasing the variety of ingredients used as DPP-IV inhibitors, there is a demand for the development of new DPP-IV inhibitors using naturally occurring ingredients.

[0005] It has also been reported that black ginger extract has a blood glucose lowering effect in obese model mice but has no significant effect on normal mice (Non-Patent Document 1), and that bakuchiol extracted from Hollandaise has antihyperglycemic activity in obese model mice (Patent Document 4, Non-Patent Document 2). However, there is a demand for extracts derived from natural products that have a blood glucose lowering effect in healthy individuals without obesity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-63286 [Patent Document 2] Special Publication No. 2007-537231 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-023450 [Patent Document 4] Patent Application No. 2008-511297 [Non-patent literature]

[0007] [Non-Patent Document 1] J Nat. Med. 2011 65:73-80 [Non-patent document 2] Biol. Pharm. Bull. 1999 22:1137-1140 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to discover a novel extract derived from a natural product having DPP-IV inhibitory activity, and to provide a DPP-IV inhibitor, a blood glucose level increase suppressant, and an antidiabetic agent. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above-mentioned problems and have found that black ginger extract and Hollandaise extract have DPP-IV inhibitory activity. Based on this finding, further research has led to the completion of the present invention.

[0010] That is, the present invention provides the following aspects. Item 1. A dipeptidyl peptidase IV inhibitor containing black ginger and / or Dutch jasmine as active ingredients. Item 2. A blood glucose level suppressant comprising the dipeptidyl peptidase IV inhibitor according to Item 1. Item 3. The blood glucose level increase inhibitor according to Item 2, wherein the blood glucose level increase is not accompanied by obesity. Item 4. An agent for preventing, treating, or ameliorating type 2 diabetes, hyperglycemia, diabetic complications, or insulin-resistant diseases, comprising the dipeptidyl peptidase IV inhibitor according to Item 1. Item 5. A food or beverage composition comprising the dipeptidyl peptidase IV inhibitor according to Item 1. Item 6. A food or drink comprising the composition for food or drink according to Item 5. [Effects of the Invention]

[0011] According to the present invention, DPP-IV is inhibited using black ginger extract and Hollandaise extract derived from natural products, and therefore it is possible to provide a DPP-IV inhibitor, a blood glucose level increase suppressant, and an antidiabetic agent that are highly safe and can be taken daily as food, drink, etc. It is also possible to provide a DPP-IV inhibitor, a blood glucose level increase suppressant, and an antidiabetic agent that have a blood glucose level lowering effect even in healthy individuals without obesity. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1. Dipeptidyl peptidase IV inhibitors The dipeptidyl peptidase IV inhibitor of the present invention is characterized by containing black ginger and / or Dutch jasmine as an active ingredient. The dipeptidyl peptidase IV inhibitor of the present invention will be described in detail below.

[0013] Black ginger (Kaempferia parviflora), the active ingredient of the present invention, is also known as black ginger and is a plant of the ginger family (Zingiberaceae). The part used as the raw material may be any of the rhizome, root, stem, leaf, seed, flower, etc., but the rhizome is preferred. The black ginger used as the raw material may be subjected to the extraction treatment as is, or, if necessary, may be dried and then crushed or powdered before being subjected to the extraction treatment.

[0014] The active ingredient of the present invention, Psoralea corylifolia, is a plant of the Fabaceae family. The part of the plant used as a raw material may be any of the roots, stems, leaves, seeds, flowers, etc., but seeds are preferred. The Psoralea corylifolia used as a raw material may be subjected to the extraction treatment as is, or, if necessary, may be dried and then crushed or powdered before being subjected to the extraction treatment.

[0015] The extraction treatment can be carried out by solvent extraction treatment, supercritical extraction treatment, steam distillation treatment, etc. Among these, solvent extraction treatment is preferred.

[0016] The extraction solvent used in the solvent extraction treatment is not particularly limited, but examples include water, hot water, lower alcohol, alkaline solution, and mixtures thereof. It is preferable to use water containing 0 to 100% by mass of lower alcohol, i.e., water or a hydrous lower alcohol with a lower alcohol content of 100% by mass or less, as the extraction solvent.

[0017] The lower alcohol is a monohydric alcohol having 1 to 5 carbon atoms, and specific examples thereof include ethanol, propanol, butanol, pentanol, etc. These lower alcohols may be used alone or in combination of two or more. Among these lower alcohols, ethanol is preferred.

[0018] The content of the lower alcohol in the extraction solvent may be 0 to 100% by mass, and from the viewpoint of efficiently obtaining an extract, it is preferably 5 to 95% by mass, more preferably 10 to 90% by mass.

[0019] In the extraction process, the amount of black ginger and / or Dutch jasmine to be immersed in the extraction solvent is not particularly limited, but may be set to, for example, about 1 to 1000 g, preferably about 30 to 500 g, and more preferably about 50 to 300 g, in dry weight terms per 1 L of solvent.

[0020] The temperature conditions during extraction are not particularly limited, but may be, for example, about 0 to 100°C, preferably about 10 to 100°C, more preferably about 15 to 95°C, and even more preferably about 20 to 90°C.

[0021] The time conditions for the extraction treatment are not particularly limited, but may be, for example, about 1 to 1440 minutes, preferably about 10 to 300 minutes, and more preferably about 20 to 120 minutes.

[0022] After the extraction treatment, the liquid fraction is recovered by solid-liquid separation to obtain a liquid extract. The obtained extract may be used as a liquid extract as is, or, if necessary, may be used as a concentrated extract or a dried extract after removing some or all of the solvent.

[0023] The DPP-IV inhibitory activity of the present invention can be suitably used as an agent for suppressing blood glucose level elevation, an antidiabetic agent, etc. These uses will be described in detail in the section "2. Agents for suppressing blood glucose level elevation, and antidiabetic agents."

[0024] 2. Blood sugar level suppressant and antidiabetic agent Incretins promote insulin secretion and inhibit the secretion of glucagon, which increases blood glucose levels, and DPP-IV inhibition can suppress the degradation of incretins. Therefore, black ginger extract and / or Hollandaise extract can also be used as an agent for suppressing blood glucose levels or an antidiabetic agent. Here, the antidiabetic agent is used for the purpose of preventing or treating type 2 diabetes.

[0025] The blood glucose level rise inhibitor or antidiabetic agent of the present invention may contain at least one of black ginger extract and Hollandaise extract as an active ingredient, but it is preferable to contain both of these, as this will enable the agent to exhibit even more excellent DPP-IV inhibitory activity.

[0026] Furthermore, since the DPP-IV inhibitor of the present invention is also effective against elevated blood glucose levels not associated with obesity, it can also be used as an agent for suppressing elevated blood glucose levels or as an antidiabetic agent in healthy individuals who are not obese.

[0027] The DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used by oral ingestion or administration. The intake or administration amount of the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention may be an amount effective for inhibiting DPP-IV in a living body, and may be appropriately determined depending on the product form to be used, etc. For example, the daily intake or administration amount for an adult is 0.1 mg to 10,000 mg, preferably 1 to 5,000 mg, and more preferably 5 to 3,000 mg, calculated as the dry weight of the black ginger extract and / or Hollandaise extract.

[0028] The DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used by being incorporated into a product that is required to have a DPP-IV inhibitory effect, a blood glucose level increase inhibitory effect, or an antidiabetic effect. Products that can incorporate the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention are not particularly limited, as long as they are orally ingested or orally administered, and examples thereof include foods and beverages, pharmaceuticals, etc.

[0029] The dosage form of a product containing the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention may be any of solid, semi-solid, liquid, etc., and is appropriately selected depending on the type and use of the product. Products containing the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention may contain food materials, food additives, nutritional components, pharmaceutically acceptable base materials, pharmaceutically acceptable additives, pharmacological components, etc., depending on the type, dosage form, etc., within the range that does not impair the effects of the present invention.

[0030] When the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used in the food and beverage field, the black ginger extract and / or Hollandaise extract may be prepared into a desired form, either as is or in combination with other food materials or additives, and provided as a DPP-IV inhibitory food and beverage, a blood glucose level increase inhibitor, or an antidiabetic food and beverage. Examples of such foods and beverages include general foods and beverages, as well as foods with health claims (including foods for specified health uses, foods with nutrient functions, and supplements), and foods for patients. Foods for patients can be provided for patients who require DPP-IV inhibition, suppression of blood glucose level increase, or prevention or treatment of diabetes. The form of these foods and beverages is not particularly limited, but specific examples include sweets such as chocolate, cookies, biscuits, chewing gum, caramels, etc.; energy bars or balanced nutritional foods; frozen desserts such as ice cream, ice milk, lacto ice cream, and frozen desserts; dairy products such as yogurt and pudding; bakery products; noodles; jams; sauce bases for curry, stew, etc.; rice bowl bases; seasoning ingredients such as kamameshi bases; freeze-dried foods; sauces and other ingredients; seafood paste products; cereals (processed grain products); supplements such as capsules (soft capsules, hard capsules), tablets, granules, and powders; soft drinks, milk drinks, lactic acid bacteria drinks, carbonated drinks, fruit juice drinks, vegetable drinks, vegetable and fruit drinks, powdered drinks, coffee drinks, etc.

[0031] Furthermore, when the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used in the food and beverage field, the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention can be provided alone or in combination with other components as a food additive for inhibiting DPP-IV, a food additive for suppressing blood glucose level increase, or a food additive for antidiabetic purposes.

[0032] When the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used in a food or beverage, the amount of the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent in the food or beverage may be appropriately set within a range that satisfies the aforementioned intake amount depending on the type and form of the food or beverage, but an example of such a range is 0.0001 to 90% by mass, preferably 0.0005 to 75% by mass, and more preferably 0.001 to 50% by mass of black ginger extract and / or Hollandaise extract in the food or beverage, calculated on a dry weight basis.

[0033] Furthermore, when the DPP-IV inhibitor, blood glucose level increase suppressant, or antidiabetic agent of the present invention is used in the pharmaceutical field, the black ginger extract and / or Hollandaise extract may be prepared into a desired dosage form alone or in combination with other pharmacological ingredients, pharmaceutically acceptable bases, additives, etc., and provided as a DPP-IV inhibitory drug, blood glucose level increase suppressant, or antidiabetic drug. The form of such a drug is not particularly limited, and specific examples include oral drugs such as drinks, tablets, pills, powders, fine granules, granules, capsules (including hard capsules and soft capsules), troches, chewable tablets, extracts (including soft extracts, dry extracts, etc.), jellies, syrups, and spirits.

[0034] When the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent of the present invention is used in a pharmaceutical product, the amount of the DPP-IV inhibitor, blood glucose level increase inhibitor, or antidiabetic agent in the pharmaceutical product may be appropriately determined within a range that satisfies the above-mentioned dosage amount depending on the type and dosage form of the pharmaceutical product, for example. For example, the amount of black ginger extract and / or Hollandaea extract in the pharmaceutical product may be in a range of 0.0001 to 90% by mass, preferably 0.0005 to 75% by mass, and more preferably 0.001 to 50% by mass, calculated on a dry weight basis. [Example]

[0035] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0036] 1. Preparation of DPP-IV Inhibitors Example 1: Preparation of Black Ginger Extract 30 mL of 99.5% ethanol was added to 3 g of dried powder of black ginger rhizome and stirred at room temperature for 30 minutes for extraction. After extraction, the extract was filtered using qualitative filter paper No. 2 (Advantec Toyo). The extract was then dried to obtain 0.165 g of dried extract.

[0037] Example 2: Preparation of Hollandaise Extract 30 mL of 99.5% ethanol was added to 3 g of dried powder of Hollandaise seeds and stirred at room temperature for 30 minutes for extraction. After extraction, the mixture was filtered using qualitative filter paper No. 2 (Advantec Toyo) to obtain an extract. The extract was then dried to obtain 0.751 g of dried extract.

[0038] Comparative Example 1: Preparation of ginger extract 30 mL of 99.5% ethanol was added to 3 g of dried ginger rhizome powder and stirred at room temperature for 30 minutes for extraction. After extraction, the extract was filtered using qualitative filter paper No. 2 (Advantec Toyo Co., Ltd.). The extract was then dried to obtain 0.133 g of dried extract.

[0039] Comparative Example 2: Preparation of banaba extract 30 mL of 99.5% ethanol was added to 3 g of dried banaba leaf powder and stirred at room temperature for 30 minutes for extraction. After extraction, the extract was filtered using qualitative filter paper No. 2 (Advantec Toyo Co., Ltd.). The extract was then dried to obtain 0.164 g of dried extract.

[0040] 2. Confirmation of DPP-IV inhibitory activity of black ginger extract and Hollandaise extract 2-1. Test method The DPP-IV inhibitory activity of black ginger extract and Hollandaise extract was measured. TM The measurement was carried out using Protease Assay (G8350, manufactured by Promega). The specific measurement conditions are as follows.

[0041] <Material> buffer solution 1M Tris-HCl (pH 8.0, Nippon Gene Co., Ltd.) was diluted 100-fold with ultrapure water to prepare 10 mM Tris-HCl (pH 8.0). substrate solution :DPPIV-Glo included in the kit TM A 10 mM substrate solution was prepared by adding 25 μL of ultrapure water to the substrate powder. Luciferin detection reagent : The Luciferin Detection Reagent powder included in the kit contains DPPIV-Glo TM The entire volume of 10 mL of buffer was added and mixed before use. Measurement reagents 20 μL of the substrate solution was added to 10 mL of the luciferin detection reagent and mixed thoroughly to adjust the substrate concentration to 20 μM. Enzyme solution A 0.5 mg / mL solution of Dipeptidylpeptidase IV, human recombinant (manufactured by BioVision) was diluted 16,000-fold with the buffer solution and used. Sample liquid The extracts obtained in Examples 1 and 2 or Comparative Examples 1 and 2 were adjusted to a concentration of 400 μg / mL using dimethyl sulfoxide (DMSO, Fujifilm Wako Pure Chemical Industries, Ltd.) and used. Sample solution (negative control) :DMSO was used. Sample solution (positive control) P32 / 98 (BML-PI142-0010, Enzo Life Sciences) was added using DMSO to a concentration of 19.2 μM.

[0042] <Method> Five microliters of the assay reagent, 1 microliter of the sample solution, and 4 microliters of the enzyme solution were added to each well of a 384-well plate and incubated at room temperature for 30 minutes. The 384-well plate was then inserted into a microplate reader (EnVision 2105, PerkinElmer) and the luminescence intensity was measured. Using the medical statistical analysis software GraphPad Prism 9 (MDF), the luminescence intensity of the sample solution (negative control) was set to 100% and that of the sample solution (positive control) to 0%, and the DPP-IV inhibition rate (%) of the extracts obtained in Examples 1 and 2 or Comparative Examples 1 and 2 was calculated.

[0043] The DPP-IV inhibition rate (%) of the extracts obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was calculated according to the following formula 1. (Formula 1) DPP-IV inhibition rate (%) = (1 - Y / X) x 100 X: Luminescence intensity of control Y: Emission intensity of the sample

[0044] 2-2. Test results The results are shown in Table 1. The inhibitory rates of the extracts obtained in Examples 1 and 2 exceeded 80%, but the ginger extract (Comparative Example 1), which belongs to the same Zingiberaceae family as black ginger, showed no inhibition, and the banaba extract (Comparative Example 2), which is known to have a blood glucose lowering effect, showed an inhibition rate of 9.0% or less. In other words, it was confirmed that an extract exhibiting higher DPP-IV inhibitory activity was obtained.

[0045] [Table 1]

Claims

1. A dipeptidyl peptidase IV inhibitor containing extracts of black ginger and / or Dutch ibis as active ingredients.

2. A blood glucose level suppressant comprising the dipeptidyl peptidase IV inhibitor according to claim 1.

3. The blood glucose level increase suppressant according to claim 2, wherein the blood glucose level increase is not accompanied by obesity.

4. A preventive, therapeutic or ameliorating agent for type 2 diabetes, hyperglycemia, diabetic complications or insulin-resistant diseases, comprising the dipeptidyl peptidase IV inhibitor according to claim 1.

5. A food or beverage composition comprising the dipeptidyl peptidase IV inhibitor according to claim 1.

6. A food or drink comprising the composition for food or drink according to claim 5.

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