Composition

Abstract

The present invention provides a composition that stably contains ergothioneine and in which the decrease of ergothioneine over time is suppressed. [Solution] A composition comprising ergothioneine, a compound containing a sulfur atom and an amino group in its molecule, and water.

Description

Technical Field

[0001] The present disclosure relates to a composition.

Background Art

[0002] Ergothioneine (EGT) is a kind of rare amino acid and is a natural product derived from mushrooms (basidiomycetes), Aspergillus oryzae, etc. Ergothioneine is known to have excellent antioxidant ability, has a high ability to scavenge hydroxyl radicals that cause natural aging, and also has an effect of inhibiting the generation of hydroxyl radicals. Furthermore, it is known that it can also scavenge singlet oxygen that causes photoaging. For example, in Document 1, by adjusting the pH of a composition containing ergothioneine and / or adding a storage stabilizer such as an antioxidant such as an ultraviolet absorber, ascorbic acid, and a chelating agent such as edetic acid or its salt to the composition, a technique for suppressing the odor change and / or color change of a composition containing ergothioneine over time has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] However, although the technique described in Patent Document 1 has been made from the viewpoint of suppressing the odor change and / or color change of a composition containing ergothioneine, there is no attention paid to the stability of ergothioneine itself in the composition. According to the study by the present inventors, it has been found that ergothioneine is oxidized and decreased over time in the composition, and the long-term stabilization effect of ergothioneine is not sufficient.

[0005] The object of one embodiment of the present disclosure is to provide a composition that stably contains ergothioneine and in which the decrease of ergothioneine over time is suppressed. [Means for solving the problem]

[0006] This disclosure includes the following aspects:

[0007] [1] A composition comprising ergothioneine, a compound containing a sulfur atom and an amino group in its molecule, and water. [2] The composition according to [1], which is a cosmetic composition.

[0008] [3] The composition according to [1] or [2], wherein the compound containing a sulfur atom and an amino group in the molecule has a molecular weight of less than 900. [4] The composition according to any one of [1] to [3], wherein the compound containing a sulfur atom in the molecule is a water-soluble compound having an -SH group in the molecule. [5] The composition according to any one of [1] to [4], wherein the compound containing a sulfur atom and an amino group in the molecule is an antioxidant. [6] The composition according to any one of [1] to [5], wherein the compound containing a sulfur atom and an amino group in the molecule is at least one selected from the group consisting of thiotaurine, glutathione, cysteine, and hypotaurine.

[0009] [7] The composition according to any one of [1] to [6], wherein the amount of ergothioneine in a compound containing a sulfur atom and an amino group in the molecule is in the range of 0.0001 to 0.5 by mass. [Effects of the Invention]

[0010] According to one embodiment of the present disclosure, it is possible to provide a composition that stably contains ergothioneine and in which the decrease of ergothioneine over time is suppressed. [Modes for carrying out the invention]

[0011] The embodiments for implementing this disclosure will be described in detail below. However, the present invention is not limited to the embodiments described below. In the embodiments described below, the components are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and they do not limit this disclosure.

[0012] In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding compound. If multiple substances corresponding to each component are present in the composition, the content of each component means the total content of those multiple substances present in the composition unless otherwise specified.

[0013] In this disclosure, the term "ergothioneine" is used to encompass both ergothioneine alone and derivatives of ergothioneine. In this disclosure, "water-soluble" means that the component can dissolve in water at a liquid temperature of 25°C and pH 7.0 at a concentration of 1% by mass or more.

[0014] The composition of this disclosure comprises ergothioneine (also referred to as component A), a compound containing a sulfur atom in its molecule (also referred to as component B), and water. The composition disclosed herein comprises component A, component B, and water, and may optionally contain other components. Furthermore, there are no particular restrictions on the dosage form of the composition disclosed herein; it may be an aqueous composition or an emulsified composition. The composition disclosed herein may also be a liposome-containing composition containing liposomes encapsulating component A. The liposome-containing composition will be described later.

[0015] Since the component A and the component B in the present disclosure are water-soluble, when the composition contains an aqueous phase and an oil phase, the component A and the component B are preferably contained in the aqueous phase in a state dissolved in water.

[0016] The composition of the present disclosure contains ergothioneine (component A), a compound containing a sulfur atom in the molecule (component B), and water, thereby stably containing ergothioneine and suppressing the decrease of ergothioneine over time. Although the action by which the composition of the present disclosure exhibits the above effects is not clear, one possibility is considered as follows. By including a compound containing a sulfur atom and an amino group in the molecule (component B) in the composition, it is considered that the thiol group in the molecule of ergothioneine (component A) and the component B form some interaction, thereby suppressing the oxidation of the component A. Among them, when the component B is a low molecular weight compound with a molecular weight of less than 900 and is a water-soluble compound, it is presumed that an interaction is more likely to be formed between the component B and the thiol group of the component A, and the effect becomes better. In particular, when the amino group-containing compound containing a sulfur atom contains a thiol group, it is considered possible that the thiol group has a very strong reducing power, cleaves the disulfide bond generated by the oxidation of ergothioneine, and reduces it back to ergothioneine again.

[0017] Hereinafter, each compound that the composition of the present disclosure may contain will be described more specifically.

[0018] [Ergothioneine (Component A)] The composition of the present disclosure contains ergothioneine. In the present disclosure, the term ergothioneine includes ergothioneine and derivatives of ergothioneine. Ergothioneine is a water-soluble compound. Ergothioneine is known as a component having antioxidant ability derived from natural products.

[0019] Ergothioneine is known as a compound having the following structure.

[0020] [ka]

[0021] The structures of ergothioneine derivatives are shown below.

[0022] [ka]

[0023] In the above formula, X is -OR 1 or -NR 1 R 2 Represents R, R 1 and R 2 Each of these independently represents a hydrogen atom, a C1-C18 alkyl group, a C1-C18 alkenyl group, or a C1-C18 acyl group. The alkyl group, alkenyl group, or acyl group may form a salt. The alkyl group may be linear or branched. The alkyl group, alkenyl group, or acyl group may be substituted with a hydroxyl group, an esterified hydroxyl group, a halogen atom, a carboxyl group and its derivatives, an amine group and its derivatives, and may contain heteroatoms, such as an oxygen atom or an ionic atom, in the chain. The ergothioneine derivatives of this disclosure include β-hydroxyergothioneine.

[0024] The ergothioneine that can be used in the compositions of this disclosure is not particularly limited as long as it is commonly used in pharmaceuticals, quasi-drugs, and cosmetics. Ergothioneine can be extracted from mushrooms, such as those of the Pleurotaceae family. Compounds obtained by known methods such as fermentation and chemical synthesis can also be used. Among these, ergothioneine extracted from mushrooms is preferred from the viewpoint of being derived from natural products and having a high yield.

[0025] Commercially available ergothioneine products include powders sold as ergothioneine, or compositions containing pre-dissolved ergothioneine. Examples of commercially available products include L-Ergothioneine from Asahi Trading Co., Ltd., AntiOxd-Ex from Shenzhen Readline Biotech Co., Ltd., Bioyout®-EGT Pure ultra-high purity ergothioneine from BLOOMAGE BIOTECHNOLOGY Corp., Ltd., THIOTAINE from AGI Dermatics, and Natural ERG Liquid from Koei Kogyo Co., Ltd.

[0026] The composition of this disclosure may contain only one type of component A, or it may contain two or more types of component A, such as ergothioneine and an ergothioneine derivative. There are no particular restrictions on the ergothioneine content in the compositions of this disclosure, and it can be appropriately selected depending on the purpose. In particular, from the viewpoint of obtaining sufficient antioxidant effect, it is preferable that the content be 1 ppm to 10,000 ppm by mass, and more preferably in the range of 2 ppm to 100 ppm, relative to the total amount of the composition.

[0027] Since ergothioneine is a water-soluble compound, it may be included directly in aqueous compositions or encapsulated as an aqueous component in liposomes. Details regarding liposomes will be described later.

[0028] [Compounds containing a sulfur atom and an amino group in the molecule (component B)] The compound (component B) containing a sulfur atom and an amino group in its molecule in the composition of this disclosure is preferably a compound with a molecular weight of less than 900, as this facilitates formulation. In this disclosure, the term "amino group" refers to -NH2. In particular, component B is preferably a water-soluble compound having an -SH group in its molecule. The water solubility of component B facilitates interaction with component A in the presence of water, which is thought to contribute to the stability of component A.

[0029] In particular, it is preferable that component B itself has antioxidant properties from the viewpoint of improving the stability of component A, and therefore, it is preferable that component B is an antioxidant. The antioxidant component B is preferably at least one selected from the group consisting of thiotaurine (structure B-1 below), glutathione (structure B-2 below), cysteine ​​(structure B-3 below), and hypotaurine (structure B-4 below), all of which are amino group-containing compounds containing a sulfur atom and an amino group in their molecule. The structure containing a sulfur atom in its molecule is more preferably an amino group-containing compound that contains a thiol group, i.e., an amino group-containing compound containing a thiol group, and even more preferably at least one selected from the group consisting of thiotaurine, glutathione, and cysteine.

[0030] [ka]

[0031] The composition of this disclosure may contain only one type of component B, or it may contain two or more types of component B. There are no particular restrictions on the content of component B in the compositions of this disclosure, and it can be appropriately selected depending on the type of component B and the intended use of the composition. In particular, from the viewpoint of obtaining sufficient stabilization effect of component A, the content of component B is preferably 0.001% to 3.0% by mass, more preferably 0.02% to 1.0% by mass, and even more preferably 0.05% to 0.6% by mass, based on the total amount of the composition.

[0032] Regarding the ratio of the content of component A to component B, the content of component A relative to component B (A / B) is preferably in the range of 0.00001 to 0.5 by mass, more preferably in the range of 0.0001 to 0.2, and even more preferably in the range of 0.0001 to 0.1, from the viewpoint of achieving a better stabilizing effect of ergothioneine.

[0033] [water] The compositions disclosed herein include water. Examples of water include deionized water, pure water, purified water, and tap water. Among these, deionized water, pure water, and purified water are preferred because they contain fewer impurities and can be used for various purposes, with purified water being more preferred. Due to the low level of impurities in the water, the compositions of this disclosure can be suitably applied, for example, to cosmetic compositions.

[0034] The water content relative to the total mass of the composition of this disclosure is not particularly limited and can range from 1% by mass to 99% by mass. For example, when the composition of this disclosure is applied to a liposome-containing composition described later, the water content relative to the total mass of the composition is preferably 1% to 99% by mass, more preferably 10% to 95% by mass, and even more preferably 20% to 90% by mass. In this context, "water content relative to the total mass of the liposome-containing composition" refers to the total amount of water contained in the inner aqueous phase and the outer aqueous phase relative to the total mass of the liposome-containing composition.

[0035] <<Method for producing the composition>> One preferred method for producing the composition of this disclosure is a method that includes mixing component A, component B, and water (hereinafter referred to as the "mixing step" as appropriate). In the mixing process, component A, component B, and water are mixed. The method of mixing these components is not particularly limited. For example, component A, component B, and water may be mixed together, or component A and component B may be added to the water while stirring and then mixed.

[0036] The mixing method is not particularly limited, and any commercially available mixing method may be used. Mixing methods include stirrers, paddle mixers, impeller mixers, homomixers, disperser mixers, ultramixers, high-pressure homogenizers, ultrasonic homogenizers, and the like.

[0037] The temperature at which each component is mixed is not particularly limited and can be set as appropriate. It is generally preferable to set it to 4°C to 85°C, and more preferably to 20°C to 70°C. The stirring conditions when mixing each component are not particularly limited as long as the components are thoroughly mixed, and can be set appropriately depending on the mixing method. For example, when using a homomixer as the mixing method, the components can usually be stirred at 500 rpm (revolutions per minute; the same applies hereafter) to 8000 rpm for 5 to 60 minutes.

[0038] The manufacturing method for producing the compositions of this disclosure may include steps other than the mixing step described above (so-called other steps) as necessary. Other processes include, for example, defoaming, heat sterilization, cooling, and removal. Methods known in the industry may be used for the defoaming, heat sterilization, cooling, and removal processes.

[0039] The composition disclosed herein is suitable as a cosmetic composition because it exhibits good stability of ergothioneine, which has excellent antioxidant properties, and can maintain its ability to scavenge hydroxyl radicals, which are a cause of natural aging, for a long period of time.

[0040] The compositions of this disclosure are preferably cosmetic compositions. In this disclosure, the cosmetic composition may be the cosmetic itself, or it may be a raw material composition used to obtain the cosmetic.

[0041] The compositions of this disclosure will be further described below with reference to examples of preferred embodiments. Examples of embodiments to which the compositions of this disclosure may be applied include liposome-containing compositions, aqueous compositions, and emulsified compositions. Compositions of these embodiments are suitable as cosmetic compositions.

[0042] <Liposome-containing composition> One embodiment of the composition of this disclosure is a liposome-containing composition. In other words, in the compositions of this disclosure, ergothioneine may be encapsulated in liposomes. In this disclosure, “liposome” means a closed vesicle formed of a lipid bilayer. A liposome comprises a solution present within the closed vesicle (internal aqueous phase) and a solution that disperses the liposome (external aqueous phase). Liposomes with a single lipid bilayer are called single-lamellar structures, and those with multiple lipid bilayers are called multi-lamellar structures. The liposomes in this disclosure may be either single-lamellar liposomes or multi-lamellar liposomes. It is preferable that the liposomes include single-lamellar liposomes.

[0043] Because the composition of this disclosure is aqueous and has good antioxidant activity, ergothioneine can be retained in the internal aqueous phase as an aqueous active ingredient (e.g., a cosmetic ingredient) to form liposomes suitable for cosmetic compositions.

[0044] (Oily components) Known components can be used as the oily components contained in the lipid bilayer that forms the liposome. Examples of oily components included in the lipid bilayer that forms liposomes include phospholipids, polyoxyethylene phytosterols, phytosterols other than polyoxyethylene phytosterols, and cholesterol. Furthermore, emollients such as phytosteryl oleate may be included to improve the solubility of oily components.

[0045] Examples of phospholipids include lecithin, a phospholipid derived from natural products. Lecithin may also be a derivative, and examples of lecithin derivatives include hydrogenated lecithin and compounds obtained by introducing polyethylene glycol, aminoglycans, etc., into the phospholipids in lecithin. Among these, hydrogenated lecithin is preferred from the viewpoint of oxidative stability.

[0046] Polyoxyethylene phytosterols are (CH2CH2-O)n This is a phytosterol having an oxyethylene group represented by , and may also be a hydrogenated phytosterol (phytostanol). Specific examples of phytosterols include sitosterol, stigmasterol, fucosterol, spinasterol, brassicasterol, and their hydrogenated forms.

[0047] Cholesterol includes cholestanol and cholesterol derivatives. Examples of cholesterol include cholesterol, dihydrocholesterol, dehydrocholesterol, cholesteryl oleate, cholesteryl isostearate, cholesteryl hydroxystearate, and polyoxyethylene cholesteryl ether. In addition to cholesterol, which is an animal sterol, phytosterols, which are plant sterols, and phytostanols, which are hydrogenated plant sterols, can also be used.

[0048] (Other ingredients) Liposomes can also contain other components. Other ingredients include cosmetic ingredients that are typically found in cosmetics. In this disclosure, "cosmetic ingredients" means ingredients that act on the body, such as the skin, and can produce cosmetic effects, and refers to active ingredients used in cosmetics, etc. When liposomes contain cosmetic ingredients, oily components of the cosmetic ingredients are contained within the lipid bilayer, while aqueous components may be contained within the inner or outer aqueous phase. Examples of beauty ingredients include natural vitamin E, α-tocopherol, γ-nonalactone, bisabolol, vitamin A oil, hinokitiol, powdered vitamin A, tocopherol linoleate, δ-tocopherol, tocopherol linoleate, isoleucine, phenylalanine, valine, leucine, and ascorbyl tetra-2-hexyldecanoate.

[0049] From the viewpoint of solubility, the beauty ingredients contained in the internal aqueous phase are preferably water-soluble beauty ingredients, and examples include ascorbic acid, ascorbic acid stearate, sodium ascorbate disodium ascorbate sulfate, aspartic acid, aspartame, acetylglucosamine, acetylglutamic acid, acetylcysteine, acetylpantothenyl ethyl ester, adenosine triphosphate disodium, adenosine monophosphate disodium, ε-aminocaproic acid, γ-aminobutyric acid, allantoin, allantoin β-glycyrrhetinic acid, albumin, etc.

[0050] The inner aqueous phase and outer aqueous phase of the liposome-containing composition may contain other components besides water, such as aqueous solvents, physiological saline, sugars, pH adjusters, and preservatives. The liposome-containing composition may contain ethanol to facilitate the production of liposomes. Ethanol may be contained within the liposome encapsulation (i.e., encapsulated within the liposome), in the dispersion medium (i.e., the outer aqueous phase), or in both the encapsulation and the dispersion medium. Both ethanol and anhydrous ethanol, which are available as ethanol, can be used. Examples of sugars include glucose, fructose, lactose, sucrose, trehalose, lactulose, and maltitol. Examples of pH adjusters include sodium hydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate anhydrous, sodium hydroxide (caustic soda), citric acid, acetic acid, and triethanolamine. Examples of preservatives include methyl parahydroxybenzoate.

[0051] The pH of the inner and outer aqueous phases is not particularly limited, but is preferably 5 to 9, and more preferably 7 to 8. The pH of the inner and outer aqueous phases can be adjusted by using the pH adjusting agent described above.

[0052] Liposome-containing compositions can be manufactured, for example, by referring to the method for producing liposome-containing compositions described in Japanese Patent Publication No. 2023-32103.

[0053] In one embodiment, the liposome-containing composition to which the composition of the present disclosure is applied may be a cosmetic. The form of the cosmetic is not particularly limited and may be a liquid, jelly, gel, cream, solid such as a stick, or semi-solid. The liposome-containing composition is preferably a transparent cosmetic. Cosmetics include, but are not limited to, skincare cosmetics (lotions, emulsions, serums, sunscreens, etc.), body cosmetics (body lotions, etc.), scalp cosmetics, and face masks. The method for producing the compositions of this disclosure is not particularly limited. The compositions of this disclosure can be obtained using component A, component B, water, and optionally other components, according to known methods for producing compositions.

[0054] There are no particular limitations on the method for producing the liposome-containing composition obtained by applying the composition of this disclosure, and known methods for producing liposome-containing compositions can be used. Specific methods for producing the liposome-containing composition will be described later in the examples.

[0055] <Aqueous composition> One embodiment of the composition of this disclosure is an aqueous composition. The composition disclosed herein comprises ergothioneine (component A), component B, and water, and since both component A and component B are water-soluble components, it can be used as an aqueous composition as is. When an aqueous composition is used, the aqueous phase may optionally contain an aqueous solvent such as ethanol, a polyhydric alcohol, or other active ingredients such as amino acids or vitamins.

[0056] <Emulsified composition> One embodiment of the composition of this disclosure is an emulsified composition. The composition of this disclosure may be an emulsified composition prepared by using an aqueous phase containing ergothioneine (component A), component B, and water, and by using an emulsifier, an oil, and optionally other additives in combination, according to a known method for producing emulsified compositions.

[0057] All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted as being incorporated by reference. [Examples]

[0058] The compositions of this disclosure will be described in detail below with reference to examples, but the compositions of this disclosure are not limited to these examples. In the examples, unless otherwise specified, "%" refers to "mass percent" and "ppm" refers to mass percent.

[0059] <Example 1> (Preparation of oil phase composition) Hydrogenated lecithin (PC content 90% or more), polyoxyethylene phytosterol (average number of moles of oxyethylene groups added: 20, manufactured by Nikko Chemicals Co., Ltd., NIKKOL® BPS-20), cholesterol (Nippon Seika Co., Ltd., Cholesterol JSQI: component D), ascorbic acid derivative (tetra-2-hexyldecanoate ascorbyl, manufactured by Nikko Chemicals Co., Ltd., NIKKOL® VC-IP), and anhydrous ethanol were mixed and dissolved by heating and stirring in a 60°C water bath for 10 minutes to obtain an oil phase composition.

[0060] (Preparation of aqueous phase composition) A raw material for ergothioneine as component A (product name: Natural_ERG_Liquid, Koei Kogyo Co., Ltd., ergothioneine concentration: 0.03% by mass), thiotaurine as component B ((B-1) thiotaurine, Sogo Yakuko Co., Ltd.), anhydrous disodium hydrogen phosphate, sodium dihydrogen phosphate, methyl parahydroxybenzoate, and purified water were mixed and heated and stirred in a 60°C water bath for 1 hour to dissolve and obtain an aqueous phase composition. In Tables 1 to 4, the values ​​listed under Component A represent the content of the ergothioneine raw material, and the values ​​in brackets below Component A indicate the content of ergothioneine (abbreviated as EGT) relative to the total amount of the composition.

[0061] (Manufacturing of liposome-containing compositions) The aqueous and oil phase compositions obtained above were mixed and dispersed for 1 hour using a Robomix homomixer (manufactured by Tajima Chemical Machinery Co., Ltd.). Subsequently, two passes were performed at 100 MPa using a high-pressure emulsifier (Starburst Mini, manufactured by Sugino Machine Co., Ltd.) to obtain a liposome-containing composition for cosmetic use. The content of each component in the total mass of the liposome-containing composition for cosmetics is shown in Table 1. In the liposome-containing cosmetic composition obtained in Example 1, the ratio of the content of component A to component B (A / B) was 0.002 by mass. In Tables 1 and 2, the ratio of the content of component A to the content of component B is shown as (A / B), and the ratio of the content of component B to the content of component A is shown as (B / A).

[0062] <Examples 2-13, 16-17, and Comparative Examples 1-16> A liposome-containing composition for cosmetic use was prepared in the same manner as in Example 1, except that the composition of the liposome-containing composition for cosmetic use was changed as shown in Tables 1 and 2. For Examples 2 to 13, (A / B) and (B / A) are shown in Tables 1 and 2. In Comparative Examples 1 to 16, the comparative compounds shown in Tables 3 to 4, which are antioxidants or chelating agents, were used instead of component B.

[0063] Details of the other B components used in Tables 1 and 2 are as follows: (B-2) Cysteine ​​(L-cysteine, Fujifilm Wako Pure Chemical Corporation) (B-3) Glutathione (reduced glutathione, Fujifilm Wako Pure Chemical Corporation) (B-4) Hypotaurin (Hypotaurin, Sogo Yakuko Co., Ltd.)

[0064] The details of the comparative compounds for component B used in Tables 3 and 4 are as follows. APM (Magnesium Ascorbyl Phosphate: NIKKOL VC-PMG, Nikko Chemicals Co., Ltd.) APS (Sodium Ascorbyl Phosphate: Trisodium L-Ascorbic Acid 2-Phosphate, Fujifilm Wako Pure Chemical Corporation) Ferulic acid (UV absorber, antioxidant, ferulic acid, Tsukuno Foods Co., Ltd.) Sodium pyrosulfite (antioxidant, sodium pyrosulfite "for manufacturing only", Fujifilm Wako Pure Chemical Corporation) Citric acid (chelating agent, anhydrous citric acid, Fujifilm Wako Pure Chemical Corporation) EDTA (chelating agent, ethylenediaminetetraacetic acid disodium salt: 2NA (EDTA-2Na), Fujifilm Wako Pure Chemical Corporation) BHT (Antioxidant: Dibutylhydroxytoluene: 2,6-di-t-butyl-4-methylphenol, Fujifilm Wako Pure Chemical Corporation) Tocopherol (antioxidant: Riken E-Oil 800, Riken Vitamin Co., Ltd.) Avobenzone (antioxidant: Parsol 1789, DSM) OMC (2-ethylhexyl 4-methoxycinnamate: Uvinul MC80 N, BASF)

[0065] <Example 14> (Manufacturing of aqueous compositions) A mixture was obtained by mixing 1.2 parts by mass of ergothioneine as component A, 1.5 parts by mass of thiotaurine as component B, and 50 parts by mass of pure water. The resulting mixture was stirred using a magnetic stirrer for 10 minutes to achieve uniform dissolution, yielding the aqueous compositions of Examples 14 and 15.

[0066] <Example 15> The aqueous composition of Example 15 was prepared in the same manner as in Example 14, except that the amounts of ergothioneine as component A and thiotaurine as component B were changed to those shown in Table 2.

[0067] <Comparative Example 17> (Manufacturing of aqueous compositions) A mixture was obtained by mixing 1.2 parts by mass of ergothioneine as component A, 0.5 parts by mass of the comparative compound APM, and 50 parts by mass of pure water. The resulting mixture was stirred using a magnetic stirrer for 10 minutes to achieve uniform dissolution, yielding the aqueous composition of Comparative Example 17.

[0068] (Evaluation of the composition) -Evaluation of ergothioneine retention rate- The ergothioneine content in each example or comparative example composition immediately after preparation was quantified by HPLC (High Performance Liquid Chromatography, Shimadzu Corporation) before the storage test.

[0069] =Preservation Test= 5 g of each example or comparative example composition was filled into a 5 mL vial as a sample, and a storage test was conducted by storing it in a 60°C cell cooler for one week. Similarly, a storage test was conducted by holding the samples in a 60°C cell oven for two weeks. The ergothioneine content of the samples after being held for one or two weeks was similarly quantified by HPLC. The residual rate of ergothioneine was measured using the following formula. The results are shown in Tables 1 to 4. Ergothioneine retention rate (%) = (Ergothioneine content after storage test / Ergothioneine content before storage test) × 100 A higher ergothioneine retention rate was evaluated as indicating superior ergothioneine stability.

[0070] Based on the retention rate of ergothioneine after 2 weeks of retention, the retention rate of ergothioneine was evaluated by ranking it according to the following criteria. If the evaluation result was "A," "B," "C," or "D," the ergothioneine stability was considered to be within an acceptable rank. "A" was the most desirable rank. The results are shown in Tables 1 to 4. ~Standards~ A: Over 95% B: 90% or more, less than 95% C: 80% or more, less than 90% D: 70% or more, less than 80% E: 60% or more, less than 70% F: Less than 60%

[0071] Tables 1 and 2 show both the ratio of component A to component B (A / B) and the ratio of component B to component A (B / A), as previously described. In Tables 3 and 4, which relate to the comparative examples, component B is not present, so "-" is entered in the (A / B) column and "0" in the (B / A) column. In the descriptions of the content of each component in Tables 1 to 4, "-" indicates that the component is not present.

[0072] [Table 1]

[0073] [Table 2]

[0074] [Table 3]

[0075] [Table 4]

[0076] Tables 1 to 4 show that the compositions of Examples 1 to 17 exhibit good storage properties for ergothioneine. Furthermore, a comparison of Examples 1, 2, 5, and 6 revealed that when the same component B was used, a higher amount of component B tended to result in better ergothioneine stability. On the other hand, in the compositions of Comparative Examples 1 to 17, which used comparative compounds such as AMP and APS, known as antioxidants, and EDTA, known as a chelating agent, instead of component B, sufficient stability of ergothioneine was not achieved. Furthermore, a comparison between Example 1 and Examples 14 and 15, and between Comparative Example 1 and Comparative Example 17, shows that in the examples, ergothioneine exhibits good stability regardless of whether the composition is a liposome composition or an aqueous composition, while in the comparative examples, the ergothioneine's stability effect is not obtained.

Claims

1. A composition comprising ergothioneine, a compound containing a sulfur atom and an amino group in its molecule, and water.

2. The composition according to claim 1, which is a cosmetic composition.

3. The composition according to claim 1 or claim 2, wherein the compound containing a sulfur atom and an amino group in the molecule is a compound with a molecular weight of less than 900.

4. The composition according to claim 1 or claim 2, wherein the compound containing a sulfur atom and an amino group in the molecule is a water-soluble compound having an -SH group in the molecule.

5. The composition according to claim 1 or claim 2, wherein the compound containing a sulfur atom and an amino group in the molecule is an antioxidant.

6. The composition according to claim 1 or claim 2, wherein the compound containing a sulfur atom and an amino group in the molecule is at least one selected from the group consisting of thiotaurine, glutathione, cysteine, and hypotaurine.

7. The composition according to claim 1 or claim 2, wherein the content of the ergothioneine in relation to the compound containing a sulfur atom in the molecule is in the range of 0.0001 to 0.5 by mass.

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