Cosmetic composition

Abstract

To provide a cosmetic composition containing ergothioneine, in which the decrease of ergothioneine over time is suppressed. [Solution] A cosmetic composition comprising ergothioneine, at least one compound A selected from the group consisting of citric acid and disodium hydrogen phosphate, and at least one compound B selected from the group consisting of sodium citrate and sodium dihydrogen phosphate, wherein the ratio of the content of compound A to the content of compound B is 0.05 to 40 by mass.

Description

Technical Field

[0001] The present disclosure relates to a cosmetic composition.

Background Art

[0002] In recent years, in the field of cosmetics, consumer preferences have diversified. Various factors such as the effects of active ingredients, characteristic usage feelings, the appearance of products, and operability can sometimes serve as purchase incentives, and the methods of product appeals have also diversified. For example, regarding active ingredients, it is desired that the effects of the active ingredients be maintained from the shipment of the product until the consumer finishes using the product.

[0003] As one of the active ingredients incorporated into cosmetics, antioxidant components have attracted attention. Antioxidant components are a general term for components that attenuate or remove harmful reactions in which oxygen is involved in the skin (living body). As an example, ergothioneine (EGT) has particularly attracted attention. Ergothioneine is a kind of rare amino acid and is a natural product derived from mushrooms (basidiomycetes), Aspergillus fungi, 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 singlet oxygen, which causes photoaging, can also be scavenged.

[0004] Patent Document 1 discloses a method for suppressing off-odor and / or discoloration, which is characterized by adjusting the pH of a composition containing ergothioneine and / or its derivative and / or blending a storage stabilizer in the composition. Patent Document 2 discloses a cosmetic composition comprising ascorbic acid 2-glucoside and ergothioneine as cosmetically active ingredients and at least one cosmetically acceptable excipient. Patent Document 3 discloses a whitening and anti-aging composition comprising, by weight, 40 to 60 parts vitamin C, 1 to 5 parts amino acid derivative, 0.1 to 3 parts flavonoid, 0.1 to 3 parts pyran alcohol, 5 to 20 parts pH adjuster, 10 to 30 parts polyol, and 1 to 20 parts freeze-drying protective agent. The disclosed amino acid derivatives include one or any combination of ferulic acid, glutathione, arginine, carnosine, and ergothioneine. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-241013 [Patent Document 2] Japanese Patent Publication No. 2009-167169 [Patent Document 3] Chinese Patent Publication No. 116999349 [Overview of the initiative] [Problems that the invention aims to solve]

[0006] In cosmetic compositions, for the expected effects of the active ingredients to be maintained, it is important that the content of the active ingredients in the cosmetic composition is maintained over a long period of time. However, ergothioneine incorporated into cosmetic compositions oxidizes and decreases over time, posing a problem in maintaining a stable content of ergothioneine in the composition.

[0007] This disclosure has been made in view of the circumstances described above. One embodiment of this disclosure aims to solve the problem of providing a cosmetic composition that contains ergothioneine and in which the decrease of ergothioneine over time is suppressed. [Means for solving the problem]

[0008] This disclosure includes the following aspects: [1] A cosmetic composition comprising ergothioneine, at least one compound A selected from the group consisting of citric acid and disodium hydrogen phosphate, at least one compound B selected from the group consisting of sodium citrate and sodium dihydrogen phosphate, and water, wherein the ratio of the content of compound A to the content of compound B is 0.05 to 40 by mass. [2] The cosmetic composition according to [1], wherein compound A is citric acid and compound B is sodium citrate. [3] The cosmetic composition according to [2], wherein the ratio of the citric acid content to the sodium citrate content is 0.1 to 9.0 by mass. [4] The cosmetic composition according to [1], wherein compound A is disodium hydrogen phosphate and compound B is sodium hydrogen phosphate. [5] The cosmetic composition according to [4], wherein the ratio of the content of disodium hydrogen phosphate to the content of sodium dihydrogen phosphate is 0.1 to 40 by mass. [6] The cosmetic composition according to [1], wherein compound A is citric acid and compound B is sodium dihydrogen phosphate. [7] The cosmetic composition according to [6], wherein the ratio of the citric acid content to the sodium dihydrogen phosphate content is 0.05 to 6 by mass. [8] The cosmetic composition according to [1], wherein compound A is disodium hydrogen phosphate and compound B is sodium citrate. [9] The cosmetic composition according to [8], wherein the ratio of the content of disodium hydrogen phosphate to the content of sodium citrate is 0.05 to 1.5 by mass. [Effects of the Invention]

[0009] According to one embodiment of the present disclosure, a cosmetic composition is provided which contains ergothioneine and in which the decrease of ergothioneine over time is suppressed. [Modes for carrying out the invention]

[0010] Hereinafter, the cosmetic composition according to the present disclosure will be described in detail. The description of the requirements described below may be made based on typical embodiments of the present disclosure, but the cosmetic composition according to the present disclosure is not limited to such embodiments, and within the scope of the object of the present disclosure, it can be implemented with appropriate modifications.

[0011] In the present disclosure, the numerical range indicated by using "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value, respectively.

[0012] In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other stepwise descriptions. Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.

[0013] In the present disclosure, the combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the amount of each component means the total amount of a plurality of substances when there are a plurality of substances corresponding to each component, unless otherwise specified.

[0014] In the present disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

[0015] In the present disclosure, "water-soluble" means that the solubility in 100 g of water at a liquid temperature of 25°C and a pH of 7.0 is 1 mass% or more.

[0016] [Cosmetic Composition] The cosmetic composition according to the present disclosure contains ergothioneine, at least one compound A selected from the group consisting of citric acid and disodium hydrogen phosphate, at least one compound B selected from the group consisting of sodium citrate and sodium dihydrogen phosphate, and water, and the ratio of the content of compound A to the content of compound B is 0.05 to 40 on a mass basis.

[0017] There is a demand for ergothioneine as an active ingredient to be formulated in cosmetic compositions. However, ergothioneine formulated in cosmetic compositions tends to oxidize over time and the content thereof in the composition cannot be maintained. A decrease in the amount of the active ingredient in cosmetic compositions is a factor that impairs the product value. On the other hand, the cosmetic composition according to the present disclosure has the above configuration, so that the decrease in ergothioneine over time is suppressed, and thus the content of ergothioneine formulated in the cosmetic composition is favorably maintained.

[0018] On the other hand, Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-241013), Patent Document 2 (Japanese Patent Application Laid-Open No. 2009-167169), and Patent Document 3 (Chinese Patent Publication No. 116999349 Specification) do not focus on the stability of ergothioneine over time in the composition. In Patent Document 1, it is made from the viewpoint of suppressing the off-odor and / or discoloration of the composition containing ergothioneine, but there is no focus on suppressing the decrease in ergothioneine over time in the composition. In Patent Document 2, ascorbic acid 2-glucoside and ergothioneine are used as components that stimulate the repair enzyme activity of cell DNA bases chemically modified by oxidative stress, but there is no focus on suppressing the decrease in ergothioneine over time in the composition. In Patent Document 3, ergothioneine is used as one of the amino acid derivatives that contribute to the stabilization of vitamin C contained in the whitening anti-aging composition, but there is no focus on suppressing the decrease in ergothioneine over time in the composition.

[0019] Hereinafter, each component included in the cosmetic composition according to the present disclosure will be described in detail.

[0020] <Ergothioneine> The cosmetic composition according to the present disclosure contains ergothioneine. In this disclosure, the term ergothioneine includes both elemental ergothioneine and derivatives of ergothioneine. Ergothioneine is a water-soluble compound. It is known as a naturally derived component with antioxidant properties.

[0021] Elemental ergothioneine is known as a compound having the following structure.

[0022] [ka]

[0023] The structures of ergothioneine derivatives are shown below.

[0024] [ka]

[0025] 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. Derivatives of ergothioneine include β-hydroxyergothioneine.

[0026] As for ergothioneine, any type commonly used in pharmaceuticals, quasi-drugs, and cosmetics can be used without any particular restrictions. Ergothioneine can be extracted from mushrooms, such as those of the Pleurotaceae family. Alternatively, compounds obtained by known methods such as fermentation or chemical synthesis can be used as ergothioneine. Among these, ergothioneine extracted from mushrooms is preferred due to its natural origin and high yield.

[0027] 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.

[0028] The content of ergothioneine in the cosmetic composition relating to this disclosure is not particularly limited and can be appropriately selected depending on the purpose. For example, from the viewpoint of obtaining sufficient antioxidant effects, it is preferable that the amount of antioxidant in the cosmetic composition be 0.0000001% to 0.1% by mass (i.e., 0.001 ppm to 1000 ppm by mass) relative to the total amount of the composition.

[0029] <Compound A and Compound B> The cosmetic composition relating to this disclosure is It comprises at least one compound A selected from the group consisting of citric acid and disodium hydrogen phosphate, and at least one compound B selected from the group consisting of sodium citrate and sodium dihydrogen phosphate, The ratio of the content of compound A to the content of compound B is 0.05 to 40 by mass.

[0030] The cosmetic composition according to this disclosure contains compound A and compound B, and by setting the ratio of the content of compound A to the content of compound B (compound A / compound B) to a range of 0.05 to 40 by mass, the decrease of ergothioneine over time is suppressed, and the ergothioneine content in the cosmetic composition is effectively maintained.

[0031] The cosmetic composition according to this disclosure may contain compound A alone or two types. The cosmetic composition according to this disclosure may contain compound B alone or two types. Compounds A and B are pH buffering compounds, and combining them specifically enhances the effect of suppressing the decrease of ergothioneine over time. Using either compound A or compound B alone, or in combination with either compound A or compound B and another compound known as a pH buffer, does not provide the effect of suppressing the decrease in ergothioneine exhibited by the cosmetic composition according to this disclosure.

[0032] In one embodiment, it is preferable that compound A is citric acid and compound B is sodium citrate. In this embodiment, the ratio of citric acid content to sodium citrate content (citric acid / sodium citrate) is preferably 0.1 to 9.0 by mass, more preferably 0.2 to 9.0, and particularly preferably 0.4 to 3.0, from the viewpoint of suppressing the decrease of ergothioneine over time and maintaining a stable ergothioneine content in the cosmetic composition.

[0033] In one embodiment, it is preferable that compound A is disodium hydrogen phosphate and compound B is disodium hydrogen phosphate. In this embodiment, the ratio of the content of disodium hydrogen phosphate to the content of disodium hydrogen phosphate (disodium hydrogen phosphate / sodium hydrogen phosphate) is preferably 0.1 to 40 by mass, more preferably 0.5 to 40, and particularly preferably 2 to 40, from the viewpoint of suppressing the decrease of ergothioneine over time and maintaining a stable ergothioneine content in the cosmetic composition.

[0034] In one embodiment, it is preferable that compound A is citric acid and compound B is sodium dihydrogen phosphate. In this embodiment, from the viewpoint of suppressing the decrease of ergothioneine over time and maintaining a stable ergothioneine content in the cosmetic composition, the ratio of citric acid content to sodium dihydrogen phosphate content (citric acid / sodium dihydrogen phosphate) is preferably 0.05 to 6 by mass, more preferably 0.09 to 6, and particularly preferably 0.09 to 0.4.

[0035] In one embodiment, it is preferable that compound A is disodium hydrogen phosphate and compound B is sodium citrate. In this embodiment, from the viewpoint of suppressing the decrease in ergothioneine content over time and maintaining a stable ergothioneine content in the cosmetic composition, the ratio of disodium hydrogen phosphate content to sodium citrate content (disodium hydrogen phosphate / sodium citrate) is preferably 0.05 to 1.5 by mass, more preferably 0.1 to 1.5, and particularly preferably 0.2 to 0.6.

[0036] Citric acid can be used without particular restrictions, as long as it is the type commonly used in pharmaceuticals, quasi-drugs, and cosmetics. You can use commercially available citric acid. An example of commercially available citric acid is "Citric Acid" manufactured by Fujifilm Wako Pure Chemical Corporation.

[0037] Sodium citrate can be used without particular restrictions as long as it is the type commonly used in pharmaceuticals, quasi-drugs, and cosmetics. Commercially available sodium citrate can be used. An example of commercially available sodium citrate is "trisodium citrate dihydrate" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0038] Disodium hydrogen phosphate can be used without particular restrictions, as long as it is commonly used in pharmaceuticals, quasi-drugs, and cosmetics. Commercially available disodium hydrogen phosphate may be used. An example of a commercially available disodium hydrogen phosphate is "Disodium Hydrogen Phosphate" from Fujifilm Wako Pure Chemical Industries, Ltd.

[0039] Sodium dihydrogen phosphate can be used without particular restrictions, as long as it is the type commonly used in pharmaceuticals, quasi-drugs, and cosmetics. Commercially available sodium dihydrogen phosphate may be used. An example of a commercially available sodium dihydrogen phosphate is "Sodium Dihydrogen Phosphate" from Fujifilm Wako Pure Chemical Industries, Ltd.

[0040] The content of compound A and compound B in the cosmetic composition relating to this disclosure can be quantified by known methods. Specifically, it can be quantified by the method shown below.

[0041] • Citric acid The Consumer Affairs Agency's "Methods for Analyzing Food Additives in Food" (Methods for Analyzing Food Additives in Food, Consumer Affairs Agency (caa.go.jp)) describes "Citric Acid and its Compounds (001133947.pdf (caa.go.jp))".

[0042] Sodium citrate A combination of the "Citric Acid and its Compounds (001133947.pdf (caa.go.jp))" described in the Consumer Affairs Agency's "Methods for Analyzing Food Additives in Food" (Methods for Analyzing Food Additives in Food, Consumer Affairs Agency (caa.go.jp)) and the sodium ion concentration determination method described on pages 29-31 onwards of Shimadzu Corporation's Ion Chromatograph Application Data Collection (c190-0209.pdf (shimadzu.co.jp)).

[0043] • Disodium hydrogen phosphate A combination of the "Phosphoric acid and its salts, pyrophosphates, polyphosphates and metaphosphates (https: / / www.caa.go.jp / policies / policy / standards_evaluation / food_additives / analysis / assets / 001135613.pdf)" described in the Consumer Affairs Agency's "Methods for Analyzing Food Additives in Food" (Methods for Analyzing Food Additives in Food, Consumer Affairs Agency (caa.go.jp)), and the sodium ion concentration determination method described on pages 29-31 onwards of Shimadzu Corporation's Ion Chromatograph Application Data Collection (c190-0209.pdf (shimadzu.co.jp)).

[0044] • Disodium hydrogen phosphate Consumer Affairs Agency, Methods for Analyzing Food Additives in Food (Methods for Analyzing Food Additives in Food, Consumer Affairs Agency) A combination of methods for determining sodium ion concentration, as described in "Phosphoric Acid and its Salts, Pyrophosphates, Polyphosphates and Metaphosphates" (https: / / www.caa.go.jp / policies / policy / standards_evaluation / food_additives / analysis / assets / 001135613.pdf) and the Shimadzu Corporation Ion Chromatograph Application Data Collection (c190-0209.pdf (shimadzu.co.jp)) on pages 29-31 onwards.

[0045] <Water> The cosmetic composition relating to this disclosure contains water. The water is not particularly limited, as long as it is water that can be used in cosmetics, for example. Specific examples of water include natural water, purified water, distilled water, ion-exchanged water, pure water, and ultrapure water (e.g., Milli-Q water). As for the water, purified water, distilled water, ion-exchanged water, pure water, or ultrapure water are preferred, for example, from the viewpoint of having fewer impurities.

[0046] The water content is not particularly limited, but is preferably 0.1% to 99.9% by mass relative to the total amount of the cosmetic composition.

[0047] <Other ingredients> The cosmetic composition relating to this disclosure may contain, as necessary, components other than those described herein (so-called other components), to the extent that it does not impair the effects of this disclosure. Other ingredients include, for example, additives commonly used in cosmetics (so-called cosmetics and medicated cosmetics) and quasi-drugs (hereinafter also simply referred to as "additives").

[0048] Examples of additives include the active ingredients of quasi-drug cosmetics (i.e., medicated cosmetics). Such active ingredients include allantoin, dipotassium glycyrrhizate, tranexamic acid, stearyl glycyrrhetinate, and niacinamide. In addition, examples of additives include functional ingredients that exhibit useful cosmetic effects (such as moisturizing, whitening, and skin conditioning effects) when used in cosmetics. Examples of such functional ingredients include ascorbic acid derivatives such as L-ascorbyl palmitate; carotenoids such as β-carotene, astaxanthin, zeaxanthin, lycopene, and lutein; vitamin E such as tocopherol and tocotrienol; retinol derivatives such as retinyl palmitate; ubiquinones such as coenzyme Q10; polyhydric alcohols such as diglycerin, glycerin, 1,3-butylene glycol (also referred to as "BG"; the same applies hereinafter), 1,3-propanediol, and dipropylene glycol; hyaluronic acid, erythritol Examples include polysaccharides such as itol, xylitol, glucose, sorbitol, and trehalose; sphingoglycolipids such as glucosylceramide and galactosylceramide; collagen such as hydrolyzed collagen and soluble collagen; amino acids such as acetyl hydroxyproline; ester oils such as cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol; polyethylene glycol such as PEG-75; hydrolyzed white lupin protein; nicotinamide; catechu extract; iris extract; and dipotassium glycyrrhizate. Other additives not listed above include surfactants, pH adjusters (sodium hydroxide, potassium hydroxide, hydrochloric acid, etc.), preservatives (phenoxyethanol, ethylhexylglycerin, methylparaben, propylparaben, etc.), UV absorbers, antioxidants, anti-inflammatory agents, thickeners other than acrylic thickeners, colorants, fragrances, minerals, etc. These additives may include components that perform two or more functions.

[0049] If a cosmetic composition contains other ingredients, it may contain one ingredient alone or two or more ingredients.

[0050] If the cosmetic composition contains other ingredients, the content of those other ingredients is not particularly limited and can be set as appropriate depending on the purpose.

[0051] <pH of cosmetic composition> The cosmetic composition relating to this disclosure can be appropriately set to a pH according to its intended purpose. The pH of the cosmetic composition can be adjusted, for example, to 2-10. The pH of the cosmetic composition shall be determined using a pH meter and the value obtained under conditions of a liquid temperature of 25°C. For example, a compact pH meter such as the LAQUAtwin (model number: AS-pH-22, manufactured by Horiba, Ltd.) can be used as the measuring device. However, the pH meter is not limited to this.

[0052] <Dosage Forms of Cosmetic Compositions> The cosmetic compositions relating to this disclosure can be prepared into dosage forms applicable to the cosmetic composition. The cosmetic compositions relating to this disclosure can be prepared into liquid compositions (e.g., aqueous compositions and emulsion compositions). Furthermore, the cosmetic composition according to this disclosure may also be prepared as a liquid composition, dried to obtain a dry product (e.g., powder), and then reformulated into a liquid composition by adding water at the time of use.

[0053] <Uses of cosmetic compositions> The uses of the cosmetic composition relating to this disclosure are not particularly limited. Cosmetic compositions can be used, for example, in skincare products such as creams, lotions, toners, gels, packs, and masks; haircare products such as perming agents, hair dyes, bleaches, styling agents, and hair growth products; makeup products such as eyeliners, mascaras, eyebrow pencils, lip liners, foundations, and makeup bases; cleansing products such as shampoos, conditioners, body soaps, and facial cleansers; and antiperspirants.

[0054] <Method for producing cosmetic compositions> The method for producing the cosmetic composition relating to this disclosure is not particularly limited. The cosmetic composition relating to this disclosure can be obtained using at least ergothioneine, compound A and compound B, water, and optionally other components, according to known methods for producing cosmetic compositions.

[0055] An example of a method for producing the cosmetic composition according to this disclosure is a method that includes, for example, a step of stirring and mixing ergothioneine, compound A and compound B, water, and other components as needed at 25°C (hereinafter referred to as the "mixing step" as appropriate). Other components may be added to the mixture obtained by the mixing step as needed. The following describes an example of a preferred method for manufacturing the cosmetic composition relating to this disclosure. However, matters common to the previously described cosmetic composition, such as the components of the cosmetic composition and their quantities, will not be explained.

[0056] [Mixing process] In the mixing step, at least ergothioneine, compound A and compound B, and water are mixed. The method of mixing these components is not limited to any particular method. In the mixing step, ergothioneine, compound A and compound B, and water may be mixed with other components as needed.

[0057] In the mixing step, ergothioneine, compound A and compound B, and water may be mixed together, or ergothioneine and water, and compound A and compound B and water may be mixed separately to obtain a mixture, and then the two resulting mixtures may be mixed together.

[0058] The mixing method used in the mixing process is not particularly limited. Any commercially available mixing method may be used in the mixing process. Mixing methods include stirrers, paddle mixers, impeller mixers, homomixers, disperser mixers, ultramixers, high-pressure homogenizers, ultrasonic homogenizers, and the like.

[0059] In the mixing process, the temperature at which ergothioneine, compound A, compound B, and water are mixed is not particularly limited and can be set appropriately depending on the types of components being mixed.

[0060] The stirring conditions when mixing each component are not particularly limited, as long as the components are thoroughly mixed. The stirring conditions can be set appropriately, for example, depending on the mixing method.

[0061] [Other processes] The method for producing the cosmetic composition according to this disclosure may include steps other than the mixing step (so-called other steps). Other processes include, for example, a defoaming process, a heat sterilization process, a cooling process, and a removal process. Methods known in the industry may be applied to the defoaming process, heat sterilization process, cooling process, and removal process. [Examples]

[0062] The cosmetic compositions relating to this disclosure will be described in more detail below with reference to examples. However, the cosmetic compositions relating to this disclosure are not limited to the following examples, unless they exceed the spirit of the disclosure.

[0063] [Example 1] The components shown in the Example 1 column of Table 1 were placed in a container and stirred and mixed for 10 minutes at a rotation speed of 150 rpm (revolutions per minute) using a magnetic stirrer [model number: HSD-6, manufactured by AS ONE Corporation] in an environment of ambient temperature of 25°C to obtain the cosmetic composition of Example 1.

[0064] [Examples 2-24, Comparative Examples 1-13] Except for using the compositions listed in Table 1, Table 2, Table 3, Table 4, Table 5, or Table 6, the same procedure as in Example 1 was followed to obtain the cosmetic compositions of Examples 2 to 24 and Comparative Examples 1 to 13.

[0065] [evaluation] 1. Stability of ergothioneine 1) Measurement of ergothioneine content immediately after preparation Ergothioneine was separated and quantified from each cosmetic composition immediately after preparation (within 24 hours of preparation) using high-performance liquid chromatography (HPLC). Specifically, a HILIC column (Inertsustain Amide: 4.6 mm × 150 mm, GL Sciences Inc.) was used. Solution A was a 10 mM ammonium acetate aqueous solution, and solution B was a 10 mM ammonium acetate 90% acetonitrile aqueous solution. Isocratic elution of 80% of solution B was performed at a flow rate of 1.0 ml / min. The column temperature was 40°C. Ergothioneine was detected by measuring the absorbance at 261 nm, and the amount of ergothioneine was quantified from the area value of the peaks of each substance. The obtained measured values ​​were considered to be the content immediately after preparation.

[0066] 2) Measurement of ergothioneine content over time 5g was taken from each cosmetic composition, placed in a glass container, sealed, and stored for one week at an ambient temperature of 60°C. Ergothioneine was separated and quantified from the cosmetic composition after storage using the same method as in "1) Measurement of ergothioneine content immediately after preparation". The obtained measurement values ​​were defined as the ergothioneine content over time.

[0067] 3) Evaluation The ratio of ergothioneine content after time has elapsed to the ergothioneine content immediately after preparation (hereinafter also simply referred to as the "content ratio") was calculated from the measurements obtained above. The calculated content ratio is shown in the "Content after time / Content immediately after preparation" column of Tables 1 to 6. Next, based on the calculated content ratio, the time-dependent stability of ergothioneine in the cosmetic composition was evaluated according to the evaluation criteria below. The results are shown in the "Evaluation Results" column of Tables 1 to 6. If the evaluation result rank is "A" or "B", it is determined that the decrease of ergothioneine over time is suppressed, and that the cosmetic composition has excellent ergothioneine stability. -Evaluation Criteria- A: The content ratio is 0.97 or higher. B: The content ratio is 0.94 or higher and less than 0.97. C: The content ratio is less than 0.94.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] [Table 4]

[0072] [Table 5]

[0073] [Table 6]

[0074] In Tables 1 to 6, the units of the numerical values ​​listed in the "Composition of Cosmetic Compositions" column are "mass%". In Tables 1 to 6, a "-" in the "Composition of Cosmetic Composition" column means that the cosmetic composition does not contain the ingredient corresponding to that column. In Tables 1 through 6, a "-" in the "Mass Ratio" column indicates that the cosmetic composition does not contain the ingredient corresponding to that column, and therefore the "Mass Ratio" has not been calculated.

[0075] Details of each component listed in Tables 1 to 6 are as follows:

[0076] <Active ingredients> • A mixture containing ergothioneine, BG, and water [(Natural ERG Liquid (manufactured by Koei Kogyo Co., Ltd.)]. Ergothioneine is included in the cosmetic composition in the amount (mass %) shown in parentheses in the composition column.

[0077] <Compound A> • Citric acid (anhydrous citric acid) [Product name: Citric acid, Fujifilm Wako Pure Chemical Corporation] • Sodium citrate [Product name: Trisodium citrate dihydrate, Fujifilm Wako Pure Chemical Industries, Ltd.] <Compound B> • Disodium hydrogen phosphate [Product name: Disodium hydrogen phosphate, Fujifilm Wako Pure Chemical Industries, Ltd.] • Sodium dihydrogen phosphate [Product name: Sodium dihydrogen phosphate, Fujifilm Wako Pure Chemical Industries, Ltd.]

[0078] <Comparative Compounds> • Potassium dihydrogen phosphate [Product name: Potassium dihydrogen phosphate, Fujifilm Wako Pure Chemical Industries, Ltd.] • Sodium hydroxide [Product name: Sodium hydroxide, Fujifilm Wako Pure Chemical Industries, Ltd.] • Sodium malate [Product name: DL-Disodium malate n-hydrate, Fujifilm Wako Pure Chemical Industries, Ltd.]

[0079] <Base material> ·Water [pure water]

[0080] As shown in Tables 1 to 4, the cosmetic compositions of Examples 1 to 24, which contain ergothioneine, compound A, and compound B, and in which the ratio of compound A to compound B is 0.05 to 40 by mass, all maintained or only slightly decreased the ergothioneine content before and after the passage of time, confirming that the decrease of ergothioneine over time was suppressed.

[0081] As shown in Tables 4 to 6, in Comparative Examples 1 to 4, which did not contain compound A and compound B but included a combination of the two comparative compounds; Comparative Examples 5 to 10, which did not contain compound B but included compound A and the comparative compound; and Comparative Examples 11 to 13, which contained only either compound A or compound B, it was confirmed that ergothioneine decreased significantly over time in all of these cases.

Claims

1. Ergothioneine and, A compound A selected from the group consisting of citric acid and disodium hydrogen phosphate, A compound B selected from the group consisting of sodium citrate and sodium dihydrogen phosphate, Water and, The ratio of the content of compound A to the content of compound B is 0.05 to 40 by mass. Cosmetic composition.

2. The cosmetic composition according to claim 1, wherein compound A is citric acid and compound B is sodium citrate.

3. The cosmetic composition according to claim 2, wherein the ratio of the citric acid content to the sodium citrate content is 0.1 to 9.0 by mass.

4. The cosmetic composition according to claim 1, wherein compound A is disodium hydrogen phosphate and compound B is sodium hydrogen phosphate.

5. The cosmetic composition according to claim 4, wherein the ratio of the content of disodium hydrogen phosphate to the content of sodium dihydrogen phosphate is 0.1 to 40 by mass.

6. The cosmetic composition according to claim 1, wherein compound A is citric acid and compound B is sodium dihydrogen phosphate.

7. The cosmetic composition according to claim 6, wherein the ratio of the citric acid content to the sodium dihydrogen phosphate content is 0.05 to 6 by mass.

8. The cosmetic composition according to claim 1, wherein compound A is disodium hydrogen phosphate and compound B is sodium citrate.

9. The cosmetic composition according to claim 8, wherein the ratio of the content of disodium hydrogen phosphate to the content of sodium citrate is 0.05 to 1.5 by mass.

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