Anti-glycation agent

Abstract

To provide a composition for preventing glycation of the stratum corneum.SOLUTION: An anti-glycation agent for the stratum corneum contains wild thyme (Thymus serpyllum) extract and / or Chinese milk vetch (Astragalus sinicus) extract.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an agent for preventing glycation, and more particularly to an agent for preventing the formation of advanced glycation end products (hereinafter also referred to as AGEs). [Background technology]

[0002] AGEs are substances formed by the protein glycation reaction (Maillard reaction), a non-enzymatic reaction between reducing sugars and proteins or lipids, and are one of the causes of aging (Non-Patent Document 1). AGEs are known to accumulate in the body and cause aging phenomena such as wrinkles, loss of skin elasticity, and dullness (Non-Patent Document 1).

[0003] Therefore, various compositions have been developed to inhibit glycation (i.e., the formation of AGEs) or to decompose the formed AGEs. For example, Patent Document 1 describes a protein glycation inhibitor and an AGE decomposer containing an extract of jaboticaba (Plinia cauliflora). Furthermore, Patent Document 2 describes an anti-glycation agent characterized by containing, as an active ingredient, one or more extracts selected from the group consisting of ononis extract, sophora root extract, golden silk extract, emmeiso extract, burnet extract, shell ginger extract, and Himalayan raspberry extract.

[0004] In human skin, unnecessary layers of the stratum corneum are shed at regular intervals (turnover), which helps maintain the skin's condition. Disruptions in turnover can cause the stratum corneum to become overstratified, leading to dullness and roughness of the skin. It is known that desmosomal proteins, particularly desmoglein, are involved in the exfoliation of the stratum corneum. For example, Patent Document 3 describes a composition for reducing desmoglein and improving dullness of the skin and lips. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-128847 [Patent Document 2] Japanese Patent Publication No. 2022-016060 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-37501

[0006] [Non-Patent Document 1] Research Advances on the Damage Mechanism of Skin Glycation and Related Inhibitors Nutrients. 2022 Nov; 14(21): 4588. Summary of the Invention [Problem to be solved by the invention]

[0007] While the above-mentioned prior art exists, the present inventors have discovered for the first time that desmosomes in the stratum corneum of human skin are glycated. More specifically, they have discovered for the first time that desmoglein 1, a type of protein that constitutes desmosomes (desmosomal proteins), is glycated. Because glycated desmosomes are less susceptible to enzymatic cleavage, the inventors hypothesized that glycation of the stratum corneum (especially desmosomes) inhibits normal exfoliation of the stratum corneum, resulting in roughness and dullness of the skin.

[0008] That is, the problem to be solved by the present invention is to provide a composition for preventing glycation of the stratum corneum, more specifically, a composition for preventing glycation of desmosomal proteins, particularly desmoglein 1. [Means for solving the problem]

[0009] The present invention, which solves the above-mentioned problems, provides an agent for preventing stratum corneum glycation, which contains wild thyme (Thymus serpyllum; hereinafter, also simply referred to as wild thyme) extract and / or astragalus sinicus (Astragalus sinicus; hereinafter, also simply referred to as astragalus) extract. According to the present invention, glycation of the stratum corneum can be prevented.

[0010] In a preferred embodiment of the present invention, the glycation of the stratum corneum is due to glycation of desmosomal proteins. In a more preferred embodiment of the invention, the desmosomal protein is desmoglein 1. As described above, the present inventors have found that desmosomal proteins that make up desmosomes, particularly desmoglein 1, are glycosylated. Glycated desmosomal proteins are less susceptible to enzymatic cleavage, which inhibits normal exfoliation of the stratum corneum. When normal exfoliation of the stratum corneum is inhibited, unnecessary layers of the stratum corneum do not peel off, resulting in stratification of the stratum corneum and possibly causing skin roughness. Therefore, glycation of the stratum corneum can be prevented by preventing the glycation of desmosomal proteins, especially desmoglein 1.

[0011] In a preferred embodiment of the present invention, the glycation of desmosomal proteins is glycation caused by exposure to ultraviolet light. Exposure to UV rays is known to be one of the causes of accelerated glycation (e.g., Expression of Advanced Glycation End-Products on Sun-Exposed and Non-Exposed Cutaneous Sites during the Aging Process in Humans PLoS One. 2013; 8(10): e75003.). According to the present invention, glycation of the stratum corneum can be prevented by preventing glycation of desmosomal proteins caused by exposure to ultraviolet light.

[0012] In a preferred embodiment of the present invention, the agent for preventing stratum corneum glycation is intended to prevent stiffness or dullness of the stratum corneum caused by glycation of desmoglein 1. As mentioned above, it is thought that the glycation of desmoglein 1 inhibits normal peeling of the stratum corneum. Furthermore, when normal peeling of the stratum corneum is inhibited, unnecessary stratum corneum remains on the skin, causing the stratum corneum to become overstratified, which is thought to cause roughness and dullness of the skin. Therefore, according to the present invention, it is possible to prevent the roughness and dullness of the skin, particularly the stratum corneum, caused by the glycation of desmoglein 1, and to make the skin soft and translucent.

[0013] In a preferred embodiment of the present invention, the agent for preventing stratum corneum glycation is intended for use by people who are highly exposed to ultraviolet rays. As mentioned above, exposure to ultraviolet light is known to be one of the causes of glycation. Therefore, it can be said that the stratum corneum, more specifically the desmosomal proteins in the stratum corneum, is more susceptible to glycation in people with high levels of UV exposure than in people with low levels of UV exposure. Therefore, by applying the present invention to people who are highly exposed to ultraviolet rays, glycation of the stratum corneum of people who are highly exposed to ultraviolet rays can be prevented. [Effects of the Invention]

[0014] The agent for preventing glycation of the present invention can prevent glycation of the stratum corneum, specifically by preventing glycation of desmosomal proteins (particularly desmoglein 1) in the stratum corneum. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a graph showing the results of Test Example 1. [Figure 2] FIG. 10 is a graph showing the results of Test Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0016] As used herein, "prevention of glycation" and "preventing glycation" refer to the inhibition of the formation of AGEs. In other words, the terms "prevention of glycation" and "preventing glycation" used herein are concepts that differ from the decomposition of formed AGEs.

[0017] In this specification, "stiffness (of the skin)" refers to a state in which the surface of the skin feels rough or hard when touched. In addition, in this specification, "dullness (of skin)" refers to a state in which the skin loses its original brightness, transparency and luster, and appears darker than its natural color.

[0018] The agent for preventing stratum corneum glycation of the present invention contains wild thyme extract and / or astragalus extract. In a preferred embodiment of the present invention, the agent for preventing glycation of the stratum corneum contains wild thyme extract and / or astragalus extract as active ingredients for preventing glycation of the stratum corneum. In another preferred embodiment of the present invention, the agent for preventing stratum corneum glycation contains wild thyme extract as an active ingredient. According to the present invention, glycation of the stratum corneum can be prevented.

[0019] Wild thyme (also known as Thymus vulgaris) is a plant belonging to the genus Thymus in the family Lamiaceae. Astragalus is a plant belonging to the genus Astragalus in the family Fabaceae.

[0020] Here, wild thyme extract and astragalus extract refer not only to the extracts themselves derived from wild thyme or astragalus, but also to the fractions of these extracts, purified fractions, and solvent-removed extracts, fractions, and purified products. Examples of wild thyme extract and astragalus extract include extracts using wild or cultivated plants, extracts made from plants sold as raw materials for herbal medicines, and commercially available extracts.

[0021] When extracting the above-mentioned extract, the whole plant or any part of the plant such as the roots, leaves, stems, flowers, or buds can be used for the extraction operation, but it is preferable to crush or shred these in advance to improve the extraction efficiency. Preferably, the above-ground parts of wild thyme are used, and more preferably, the whole plant and seeds of astragalus are used.

[0022] Suitable examples of extraction solvents include one or more selected from polar solvents such as water, alcohols such as ethanol, isopropyl alcohol, and butanol, polyhydric alcohols such as 1,3-butanediol and polypropylene glycol, ketones such as acetone and methyl ethyl ketone, and ethers such as diethyl ether and tetrahydrofuran. Preferably, the extraction solvent for wild thyme extract is a mixed solution of 1,3-butylene glycol and water, and the extraction solvent for astragalus extract is absolute ethanol, 1,3-butylene glycol, or a mixed solution thereof.

[0023] Specific extraction methods for the above-mentioned extract include, for example, a method in which 1 to 30 parts by mass of solvent is added to 1 mass of the part of the plant body or its dried material used for extraction, followed by immersion for several days at room temperature or for several hours at a temperature near the boiling point, cooling to room temperature, removing insoluble matter and / or solvent as desired, and fractionating and purifying by column chromatography or the like, but the extraction method is not limited to this.

[0024] The agent for preventing stratum corneum glycation of the present invention can be appropriately combined with any component used in formulation and can be in the form of an oral agent or an external agent for skin application.

[0025] When the agent for preventing stratum corneum glycation of the present invention is formulated as an oral preparation, it is preferably in the form of a food composition containing wild thyme extract and / or astragalus extract as an active ingredient, specifically in the form of a supplement having the dosage form of a general food, tablet, granule, drink, or the like.

[0026] The content of wild thyme extract and / or astragalus extract in an oral agent for preventing stratum corneum glycation varies depending on the dosage form, and the amount taken per dose is typically 0.1 mg or more, preferably 1 mg or more, and more preferably 10 mg or more, in terms of dry mass of the extract. Also, it is usually 2000 mg or less, preferably 1000 mg or less, more preferably 500 mg or less. In the case of an oral preparation containing wild thyme extract and astragalus extract, the total content of both extracts is preferably within the above-mentioned range.

[0027] When the agent for preventing stratum corneum glycation of the present invention is used as an external preparation for skin, examples of the form include cosmetics, quasi-drugs, external medicines for skin, etc. Furthermore, the dosage form thereof is not particularly limited. In a preferred embodiment of the present invention, the agent for preventing stratum corneum glycation, which is an external preparation for skin, is a cosmetic product that is expected to be used on a daily basis (for example, every day), and more preferably is a skin care cosmetic product. Examples of skin care cosmetics include face washes, cleansing agents, lotions, beauty serums, emulsions, creams, gels, sun care products, etc. They may also be in the form of face packs. The agent for preventing stratum corneum glycation may also be used as a makeup cosmetic, for example, a makeup base, foundation, lipstick, etc.

[0028] The content of wild thyme extract and / or astragalus extract in the external skin preparation is at a final concentration of 0.02% by mass or more, preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. In addition, the content of wild thyme extract and / or astragalus extract in the topical skin composition is 2% by mass or less, preferably 1.5% by mass or less, more preferably 1.2% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, and particularly preferably 0.2% by mass or less. By setting the content within the above range, glycation of the stratum corneum can be prevented. When the agent for preventing stratum corneum glycation contains wild thyme extract and astragalus extract, the total content of both extracts is preferably within the above-mentioned range.

[0029] Furthermore, the content (dry weight) of wild thyme extract and / or astragalus extract in the external skin preparation is usually 0.00001% by mass or more, preferably 0.0001% by mass or more, and more preferably 0.001% by mass or more. Moreover, it is usually 80% by mass or less, preferably 30% by mass or less, and more preferably 10% by mass or less. By setting the content within the above range, glycation of the stratum corneum can be prevented. When the agent for preventing stratum corneum glycation contains wild thyme extract and astragalus extract, the total content of both extracts is preferably within the above-mentioned range.

[0030] When the agent for preventing stratum corneum glycation of the present invention is used as a cosmetic, whitening ingredients, wrinkle-reducing ingredients, anti-inflammatory ingredients, extracts derived from animals and plants, and ingredients normally used in cosmetics other than the active ingredient may be blended as optional ingredients within a range that does not impair the glycation prevention effect (excluding wild thyme extract and astragalus extract). These optional ingredients may be commercially available and used, or may be synthesized by known methods and used. Each optional ingredient may have two or more effects (for example, a whitening effect and an anti-wrinkle effect).

[0031] As the whitening ingredient, ingredients generally used in cosmetics can be used without any particular restrictions. For example, 4-n-butylresorcinol, ascorbic acid glucoside, 3-O-ethyl ascorbic acid, tranexamic acid, arbutin, 1-triphenylmethylpiperidine, 1-triphenylmethylpyrrolidine, 2-(triphenylmethyloxy)ethanol, 2-(triphenylmethylamino)ethanol, 2-(triphenylmethyloxy)ethylamine, triphenylmethylamine, triphenylmethanol, triphenylmethane and aminodiphenylmethane, N-(o-toluoyl)cis Theic acid, N-(m-toluoyl)cysteic acid, N-(p-toluoyl)cysteic acid, N-(p-methoxybenzoyl)cysteic acid, N-benzoylserine, N-(p-methylbenzoyl)serine, N-(p-ethylbenzoyl)serine, N-(p-methoxybenzoyl)serine, N-(p-fluorobenzoyl)serine, N-(p-trifluoromethylbenzoyl)serine, N-(2-naphthoyl)serine, N-(4-phenylbenzoyl)serine, N-(p-methylbenzoyl)serine Examples of suitable benzoylserine include N-(p-methylbenzoyl)serine methyl ester, N-(p-methylbenzoyl)serine ethyl ester, N-(2-naphthoyl)serine methyl ester, N-benzoyl-O-methylserine, N-(p-methylbenzoyl)-O-methylserine, N-(p-methylbenzoyl)-O-acetylserine, N-(2-naphthoyl)-O-methylserine, dexpanthenol W, and niacinamide.

[0032] The content of the whitening ingredient in the cosmetic is usually 0.0001 to 30% by mass, preferably 0.001 to 10% by mass, and more preferably 0.01 to 5% by mass (dry mass in the case of an extract).

[0033] As the wrinkle-reducing component, any component commonly used in cosmetics can be used without any particular limitation. Examples of vitamin A or its derivatives include retinol, retinal, retinoic acid, tretinoin, isotretinoin, tocopherol retinoate, retinol palmitate, and retinol acetate.Further examples include ursolic acid benzyl ester, ursolic acid phosphate, betulinic acid benzyl ester, benzilic acid phosphate, trifluoroisopropyloxopropylaminocarbonylpyrrolidinecarbonylmethylpropylaminocarbonylbenzoylaminoacetic acid sodium, and niacinamide.

[0034] The content of the wrinkle-reducing ingredient in the cosmetic is usually 0.0001 to 30% by mass, preferably 0.001 to 10% by mass, and more preferably 0.01 to 5% by mass (dry mass in the case of an extract).

[0035] Examples of anti-inflammatory ingredients include kurarinone, glabridin, glycyrrhizinic acid, glycyrrhetinic acid, pantothenyl alcohol, niacinamide, and tranexamic acid, and preferred examples include glycyrrhizinic acid and its salts, alkyl glycyrrhetinates and their salts, and glycyrrhetinic acid and its salts. The content of the anti-inflammatory component in the cosmetic is usually 0.01 to 30% by mass, preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass (dry mass in the case of an extract).

[0036] Examples of extracts derived from plants and animals include akebia extract, asparagus extract, avocado extract, hydrangea extract, almond extract, arnica extract, aronia extract, apricot extract, ginkgo extract, fennel extract, udo extract, Siberian ginseng extract, emmeiso extract, phellodendron bark extract, Panax ginseng extract, white nettle extract, kakyō extract, pueraria root extract, chamomile extract, carrot extract, artemisia capillaris extract, licorice extract, kiwi extract, cucumber extract, and guava extract. Kisu, gardenia extract, kumazasa extract, walnut extract, black rice extract, chlorella extract, mulberry extract, kaempfer extract, alpinia zerumbet extract, gentian extract, rice extract, fermented rice extract, fermented rice bran extract, rice germ oil, salvia extract, soapwort extract, bamboo extract, zanthoxylum extract, Japanese pepper extract, shiitake mushroom extract, rehmannia root extract, lithospermum root extract, perilla extract, linden extract, meadowsweet extract, ginger extract, calamus root extract, horsetail extract, stevia extract, fermented stevia, se Yarrow extract, peppermint extract, sage extract, mallow extract, cnidium extract, Swertia japonica extract, Morus alba extract, rhubarb extract, soybean extract, Chinese laurel extract, dandelion extract, clove extract, chili pepper extract, angelica extract, calendula extract, peach kernel extract, Houttuynia cordata extract, tomato extract, natto extract, carrot extract, garlic extract, hibiscus extract, cinnamon root extract, lotus extract, parsley extract, birch extract, witch hazel extract, and holly extract Preferred examples of extracts include cypress extract, loquat extract, coltsfoot extract, butterbur extract, poria extract, loofah extract, peppermint extract, linden extract, pine extract, skunk cabbage extract, melissa extract, mozuku extract, peach extract, cornflower extract, lily extract, coix seed extract, mugwort extract, lavender extract, apple extract, rooibos tea extract, lychee extract, lettuce extract, forsythia extract, rosemary extract, Roman chamomile extract, and burnet extract.

[0037] The content (dry mass) of the optional animal and plant-derived extract in the cosmetic is usually 0.01 to 30 mass %, preferably 0.1 to 10 mass %, more preferably 0.3 to 3 mass %.

[0038] In addition to active ingredients, ingredients commonly used in cosmetics include polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene glycol, polyols such as 1,2-pentanediol, 2,4-hexylene glycol, 1,2-hexanediol, and 1,2-octanediol, fatty acid soaps (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, and triethanolamine alkyl sulfate. Anionic surfactants such as ethers, cationic surfactants such as stearyltrimethylammonium chloride, benzalkonium chloride, laurylamine oxide, imidazoline-based amphoteric surfactants (2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, etc.), betaine-based surfactants (alkyl betaine, amido betaine, sulfobetaine, etc.), amphoteric surfactants such as acyl methyl taurine, sorbitan fatty acid esters (sorbitan monostearate, sorbitan sesquioleate, etc.), glycerin fatty acids (monosodium esters), Glycerin monostearate, etc.), propylene glycol fatty acid esters (propylene glycol monostearate, etc.), hydrogenated castor oil derivatives, glycerin alkyl ether, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbitan fatty acid esters (POE-sorbitan monolaurate, etc.), POE glycerin fatty acid esters (POE-glycerin monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.) acrylate, etc.), POE alkyl ethers (POE 2-octyldodecyl ether, etc.), POE alkyl phenyl ethers (POE nonylphenyl ether, etc.), Pluronic (registered trademark) types, POE·POP alkyl ethers (POE·POP 2-decyltetradecyl ether, etc.), Tetronic (registered trademark) types, POE castor oil·hydrogenated castor oil derivatives (POE castor oil, POE hydrogenated castor oil, etc.), sucrose fatty acid esters, nonionic surfactants such as alkyl glucosides, moisturizing ingredients such as sodium pyrrolidone carboxylate, lactic acid, sodium lactate, etc.,Powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, silicic anhydride (silica), aluminum oxide, and barium sulfate, which may be surface-treated; inorganic pigments such as cobalt oxide, ultramarine, Prussian blue, and zinc oxide, which may be surface-treated; composite pigments such as sintered iron oxide and titanium dioxide, which may be surface-treated; pearling agents such as titanium dioxide, fish phosphate foil, and bismuth oxychloride, which may be surface-treated; and laked Red No. 202, Red No. 228, Red No. 226, Yellow No. 4, Blue No. 404, Yellow No. 5, Red No. 505, Red No. 230, Red No. 223, Orange No. 201, Red No. 213, Yellow 204, Yellow No. 203, Blue No. 1, and Green 20. Examples of suitable organic pigments include organic dyes such as No. 1, Purple No. 201, and Red No. 204; organic powders such as polyethylene powder, polymethyl methacrylate, nylon powder, and organopolysiloxane elastomer; lower alcohols such as ethanol and isopropanol; vitamin A or a derivative thereof, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or a derivative thereof, vitamin B12, and vitamin B15 or a derivative thereof; vitamin E such as α-tocopherol, β-tocopherol, γ-tocopherol, and vitamin E acetate; vitamin D, vitamin H, pantothenic acid, pantethine, and pyrroloquinoline quinone.

[0039] In the stratum corneum, cornified cells are adhered by desmosomes and intercellular lipids. Normally, as the stratum corneum matures, desmosomes are enzymatically cleaved one after another, causing unnecessary layers of the stratum corneum to peel off.

[0040] As described above, the present inventors have now revealed that desmosomes are glycated in human skin. Glycated desmosomes are less susceptible to the above-mentioned enzymatic cleavage, so unnecessary keratinocytes remain on the skin, causing the skin to become rough and dull. Therefore, the agent for preventing stratum corneum glycation of the present invention preferably prevents stratum corneum glycation caused by glycation of desmosomal proteins in particular. According to the present invention, glycation of the stratum corneum can be prevented.

[0041] Here, desmosomes are formed by cell membrane proteins such as desmoglein and desmocollin, and intracellular components such as desmoplakin, plakoglobin, and plakophilin. Among these, desmoglein has four isoforms: desmoglein 1, desmoglein 2, desmoglein 3, and desmoglein 4. The main component of desmosomes is desmoglein 1. Therefore, the agent for preventing stratum corneum glycation of the present invention is preferably one for preventing the glycation of desmoglein 1, among desmosomal proteins. Preventing the glycation of desmoglein 1 can effectively prevent the glycation of the stratum corneum.

[0042] Glycation in the body occurs via various pathways, including endogenous pathways such as the Maillard reaction, sugar autoxidation, lipid peroxidation, and polyol pathway, as well as exogenous pathways such as diet and tobacco (see Non-Patent Document 1). Glycation in the skin, in particular, is known to be largely influenced by ultraviolet light (e.g., Expression of Advanced Glycation End-Products on Sun-Exposed and Non-Exposed Cutaneous Sites during the Aging Process in Humans, PLoS One. 2013; 8(10): e75003). In other words, preventing the glycation of desmosomal proteins (particularly desmoglein 1) caused by UV exposure can effectively prevent glycation of the stratum corneum. Therefore, the agent for preventing stratum corneum glycation of the present invention is preferably one intended to prevent glycation of desmosomal proteins (particularly desmoglein 1) caused by exposure to ultraviolet light. Furthermore, the agent for preventing stratum corneum glycation of the present invention is preferably intended for use by people who are highly exposed to ultraviolet rays.

[0043] Here, "applying the agent for preventing stratum corneum glycation to a person who is highly exposed to ultraviolet rays" means using the agent for preventing stratum corneum glycation of the present invention on a subject for whom the agent is particularly effective, and an appropriate application method can be adopted depending on the dosage form. For example, when the agent for preventing stratum corneum glycation is an oral agent, applying the agent for preventing stratum corneum glycation of the present invention to a person who is highly exposed to ultraviolet rays means that the agent for preventing stratum corneum glycation is orally ingested by a person who is highly exposed to ultraviolet rays. Furthermore, for example, when the stratum corneum glycation preventive agent is an external preparation for skin, applying the glycation preventive agent of the present invention to a person with a high level of ultraviolet exposure means applying the stratum corneum glycation preventive agent to the skin of a person with a high level of ultraviolet exposure. "People with high UV exposure" refers to people who are exposed to an objective measure (for example, people whose daily UV exposure is 10 kJ / m 2 This includes both people who can be judged to have high UV exposure based on factors such as their daily outdoor activities (e.g., three hours or more per day), and people who subjectively believe that their UV exposure is high. It may also include people whose UV exposure has temporarily increased due to participation in outdoor events, etc.

[0044] When the stratum corneum glycation preventive agent is an external preparation for the skin, it is also preferable to apply it to areas that are highly exposed to ultraviolet rays, that is, to use it as an external preparation for the skin to be applied to areas that are highly exposed to ultraviolet rays. Areas that are highly exposed to ultraviolet rays are generally areas that are likely to be irradiated by sunlight, and may also be referred to as areas that are exposed through clothing or areas that are frequently exposed. Therefore, the agent for preventing stratum corneum glycation of the present invention is also preferably formulated as an external skin preparation to be applied to areas exposed to sunlight. For example, areas that are highly exposed to ultraviolet rays (i.e., areas exposed to sunlight) include, but are not limited to, the face, neck, hands (particularly the backs of the hands), and arms (particularly the outsides). [Example]

[0045] The present invention will be described in more detail below with reference to examples, but the technical scope of the present invention is not limited to the following examples.

[0046] <Test 1> Confirmation of stratum corneum glycation In this test, it was confirmed that the stratum corneum was glycated.

[0047] The stratum corneum was collected from the frozen skin of subjects (five women in their 20s to 70s) using a scalpel. The collected stratum corneum was solubilized, and a portion was taken to prepare a cell-solubilized sample. Desmoglein 1 was recovered by immunoprecipitation using anti-Desmoglein 1 / DSG1 antibody (Abcam) according to standard methods. The recovered material was detected by Western blotting, and the results are shown in Figure 1.

[0048] As shown in Figure 1, it was revealed that desmosomes in the human stratum corneum, particularly desmoglein 1, were glycosylated.

[0049] <Test 2> Verification of the glycation prevention effect of wild thyme extract and astragalus extract In this study, the glycation prevention effects of wild thyme extract and astragalus extract were examined.

[0050] First, BSA and wild thyme extract (extraction solvent: 1,3-butylene glycol, diluent: 1:1 mixture of 1,3-butylene glycol and water) and / or astragalus extract (extraction solvent: mixture of 1,3-butylene glycol and absolute ethanol, diluent: mixture of 1,3-butylene glycol (30% by mass), ethanol (30% by mass), and water (40% by mass)) were added to 0.15 M glucose and mixed so that the final concentration of the extract itself, including the diluent, was 0.1% by mass. The extracts contained in each test example are as follows: Test Example 1: Astragalus extract Test Example 2: Wild thyme extract Test Example 3: Wild thyme extract and astragalus extract In Test Example 3, the final concentrations (including the dilution) of the wild thyme extract and the astragalus extract were each adjusted to 0.1% by mass (total final concentration of the extracts including the dilution was 0.2% by mass). As controls, samples containing only 0.15 M glucose, a diluted solution of the above extract (a mixed solution of 1,3-butylene glycol, ethanol, and water), and BSA were also prepared. The amounts of 1,3-butylene glycol, ethanol, and water were all equal in Test Examples 1 to 3 and the Control Example.

[0051] Next, the control example and test examples 1 to 3 were incubated at 60°C for 24 hours. Finally, the concentrations of AGEs in the control example and test examples 1 to 3 were measured by ELISA. The AGE concentration in each test example is shown in Figure 2, with the AGE concentration in the control example set at 1.

[0052] As shown in FIG. 2, the AGE concentrations in Test Examples 1 to 3 were lower than the AGE concentration in the control example. Therefore, it was revealed that wild thyme extract and astragalus extract have the effect of inhibiting the formation of AGEs, i.e., the effect of preventing glycation.

[0053] The formation of AGEs (i.e., glycation reaction) is a non-enzymatic chemical reaction between the carbonyl groups of reducing sugars and amino acids in proteins. In other words, AGEs are formed when reducing sugars and proteins are combined, regardless of the type of substrate protein. Therefore, although BSA was used as the substrate protein in this test example, it is believed that the glycation reaction would occur similarly even if the substrate protein was desmoglein 1. Therefore, combining the results of Test Examples 1 and 2 suggests that wild thyme extract and astragalus extract can prevent the glycation of desmosomal proteins, particularly desmoglein 1, in the stratum corneum. [Industrial Applicability]

[0054] The present invention can prevent glycation of the stratum corneum.

Claims

1. An agent for preventing stratum corneum glycation, comprising wild thyme (Thymus serpyllum) extract and / or astragalus sinicus extract.

2. The agent for preventing stratum corneum glycation according to claim 1 , wherein the glycation of the stratum corneum is caused by glycation of desmosomal proteins.

3. The agent for preventing stratum corneum glycation according to claim 2, wherein the desmosomal protein is desmoglein 1.

4. The agent for preventing stratum corneum glycation according to claim 2, wherein the glycation of desmosomal proteins is caused by exposure to ultraviolet light.

5. The agent for preventing stratum corneum glycation according to claim 3, which is for preventing stiffness or dullness of the stratum corneum caused by glycation of desmoglein 1.

6. The agent for preventing stratum corneum glycation according to any one of claims 1 to 5, which is intended for application to people who are highly exposed to ultraviolet rays.

Images