Personal care composition containing amino acids

Abstract

The present invention relates to a personal care composition for protecting the skin from unwanted bacteria. The present invention is particularly useful for formulating a composition that allows the growth of skin commensal bacteria, such as Staphylococcus epidermidis, while inhibiting the growth of harmful bacteria, such as Escherichia coli and Staphylococcus aureus, among others. The present invention, which contains a mixture of carefully selected amino acids, therefore provides a balance of the skin microbiome.

Description

Technical Field

[0001] The present invention relates to a personal care composition for protecting the skin from unwanted bacteria. The present invention is particularly useful in formulating a composition that acts as a prebiotic for skin commensal bacteria such as Staphylococcus epidermidis, which produces metabolites shown to inhibit the growth of harmful bacteria such as Escherichia coli (E. coli) and Staphylococcus aureus among bacteria by the method of the present invention. The present invention thus provides a balance of the microbiome in the skin.

Background Art

[0002] In mammals, the skin is considered the largest organ of the body and has the largest surface area. The skin forms the first line of defense against microorganisms that can enter the body through the air, water, food, or substances that come into contact with the body. When the body becomes infected with a skin infection or a systemic infection, the conventional approach to such hygiene problems has been to treat the skin / body with antimicrobial substances that reduce or kill the pathogens. Recent research has shown that a large number of bacteria that persistently reside on the skin (called cutaneous symbiotic bacteria) do not usually cause infection in healthy individuals; rather, they are beneficial bacteria that protect the skin from disease-causing pathogens. Several mechanisms have been proposed to explain this protection, some of the common being: physically occupying space on the skin to prevent the colonization of pathogens; producing metabolites that repel harmful, and sometimes pathogenic, organisms; producing metabolites that enhance the natural defense mechanisms to prevent infection by harmful pathogens; and providing other benefits, such as maintaining the skin's pH and providing protective functions. Therefore, in recent years, there has been a trend away from the approach of treating the skin with a broad range of antimicrobial agents to kill all microorganisms present on the skin (or any other part of the body) as a means of treating infection. Rather, the approach is moving towards eliminating skin symbiotic organisms and targeting or selectively inhibiting / killing the desired microorganisms. This ensures that the skin's microorganisms are maintained in a healthy and balanced state for long-term hygiene and health.

[0003] The inventors aimed to solve the problem of selective killing of non-symbiotic skin bacteria such as Escherichia coli and Staphylococcus aureus, and directed their research towards boosting the number and functionality of skin symbiotic bacteria through the use of prebiotics / selective fermentation inducers (SFIs).

[0004] In the course of extensive research in the field of prebiotics, the inventors know that numerous carbon sources, such as carbohydrates and sugars, are known as prebiotics for the skin (e.g., International Publication No. 2013 / 122931 (P&G) publishes that topical use of dermal symbiotic prebiotics improves the health of the skin microbiome), thereby potentially improving the condition and / or appearance of the skin. In this invention, they investigated the use of nitrogen sources (e.g., amino acids) as prebiotics and, surprisingly, found that, with the exception of others, only certain selected amino acids act as prebiotics. [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, the object of the present invention is to provide a composition that ensures the growth of skin symbiotic bacteria.

[0006] Another object of the present invention is to provide a composition that reliably promotes the growth of commensal skin bacteria on the skin while inhibiting the growth of harmful microorganisms. [Means for solving the problem]

[0007] A first aspect of the present invention relates to a personal care composition comprising a combination of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid, L-tyrosine, L-glycine, and L-threonine, wherein the composition comprises less than 0.05% by weight, preferably less than 0.01% by weight, of other amino acids.

[0008] Another aspect of the present invention relates to a method for nourishing skin symbiotic bacteria, comprising the step of applying the composition of the first aspect to the skin. [Modes for carrying out the invention]

[0009] These and other aspects, features and advantages will become apparent to those skilled in the art by reading the detailed description and appended claims below. To avoid misunderstanding, any feature of one aspect of the present invention may be used in any other aspect of the present invention. The term “comprising” is intended to mean “containing,” but not necessarily “consisting of” or “composed of.” In other words, the described steps or selections do not need to be exhaustive. Note that the examples given in the following description are intended to clarify the present invention and are not intended to limit the present invention to those examples themselves. Similarly, all proportions are weight / weight ratios unless otherwise indicated. Unless otherwise clearly indicated in the examples and comparative examples, or otherwise expressly indicated, all figures in this specification and claims indicating the amount or reaction conditions of a substance, the physical properties of a substance and / or use should be understood to be modified by the term “about.” Numerical ranges expressed in the format “from x to y” are understood to include x and y. If, for a particular reason, a number of preferred ranges are listed in the format "from x to y", it is understood that all ranges combining different endpoints are also considered.

[0010] The present invention relates to a composition comprising a specific combination of selected amino acids for protecting the skin from non-symbiotic bacteria by nourishing skin symbiotic bacteria. The inventors have found that when the composition contains only seven selected amino acids, preferably five of them, more preferably three of them, excluding other amino acids, the effectiveness is better when compared to one containing one, more, or all amino acids not on the selected list. Furthermore, it relates to the use of this combination in a skin care composition as a nutrient for symbiotic bacteria. Alternatively, the present invention also relates to the use of this combination in a skin care composition as a prebiotic for symbiotic bacteria. The inventors believe that this is achieved by only the selected amino acids, which are prebiotics for skin symbiotic bacteria but not for harmful bacteria; and that this works only when amino acids not on the selected list are absent or present in small amounts.

[0011] Any choice described in the following specification with respect to one aspect of the present invention (for example, a composition or use according to the present invention) is also preferred for use in any other aspect of the present invention.

[0012] As used herein, “skin” is understood to include the skin of any part of the body (e.g., face, neck, chest, back, arms, armpits, hands, legs, buttocks, and scalp). Protecting the skin of infants is also useful. “Infant” means a child under the age of 5 years, preferably under the age of 3 years, and more preferably under the age of 1 year. The use of the compositions of the present invention against pathogens is preferably non-therapeutic and is delivered, for example, through cosmetic or personal care compositions. Furthermore, the compositions and methods of the present invention are also preferably for non-therapeutic use. Such compositions may be in the form of leave-on compositions. Alternatively and equally preferably, it may be delivered through wash-off forms to deliver selective and protective benefits to local areas of mammals, particularly humans, such as skin and / or hair. Such compositions also include any products applied to the human body for improving appearance, cleansing, or general aesthetics. The compositions of the present invention can be delivered by a topically acceptable carrier, which may be an anhydrous base, a liquid, a lotion, a cream, a foam, a scrub, a gel, or an emulsion.

[0013] The present invention relates to a personal care composition comprising a combination of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid, L-tyrosine, L-glycine, and L-threonine, and comprising less than 0.05% by weight, preferably less than 0.01% by weight, of other amino acids.

[0014] The structures and properties of amino acids useful in this invention are given in Table 1 below:

[0015] [Table 1]

[0016] A preferred embodiment of the present invention provides a composition comprising a combination of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid, and L-tyrosine, wherein the composition further comprises less than 0.05% by weight, preferably less than 0.01% by weight, of other amino acids.

[0017] A further preferred embodiment of the present invention provides a composition comprising a combination of the amino acids L-cysteine, L-serine, and L-alanine, wherein the composition further comprises less than 0.05% by weight, preferably less than 0.01% by weight, of other amino acids.

[0018] In any embodiment of the present invention, the amino acids selectively included are preferably present in an amount of 0.01 to 1% of the total weight of the composition, each of the amino acids described in the claims. Each amino acid in any embodiment of the present invention is more preferably present in an amount of at least 0.03, even more preferably at least 0.05, even more preferably at least 0.07% by weight, and optionally at least 0.1% by weight of the composition. Each amino acid in any embodiment of the present invention is more preferably present in an amount of at most 0.9% by weight, more preferably at most 0.8, even more preferably at most 0.7% by weight, and optionally at most 0.5% by weight of the composition. The composition according to the present invention contains a total amount of amino acids of 0.03 to 7%, preferably 0.05 to 5%, and most preferably 0.07 to 3% of the total weight of the composition.

[0019] "Other amino acids in amounts less than 0.05% by weight, preferably less than 0.01% by weight" means that the concentration of each amino acid not included in the selection list according to the embodiments of the present invention is less than 0.05% by weight, preferably less than 0.01% by weight of the composition. According to a particularly preferred embodiment of the present invention, the concentration of each amino acid not included in the selection list according to the embodiments of the present invention is less than 0.005% by weight of the composition, most preferably less than 0.001% by weight. According to a further preferred embodiment, the total amount of amino acids not included in the selection list according to the embodiments of the present invention is less than 0.05% of the total weight of the composition, preferably less than 0.01%, and even more preferably less than 0.005%.

[0020] According to another preferred embodiment of the present invention, a composition is provided comprising a peptide having more than three amino acids in its chain in less than 1% by weight, preferably less than 0.1% by weight. According to yet another preferred embodiment of the present invention, a composition is provided comprising less than 1% by weight, preferably less than 0.1% by weight, of protein. Thus, the benefits of the present invention are seen when the selected amino acids are included in the composition in the absence of peptides or proteins.

[0021] The selected amino acids present in the composition according to the present invention are preferably prebiotics for skin commensal bacteria. The skin commensal bacteria are preferably Staphylococcus epidermidis. The skin is protected by the present invention from non-commensal bacteria, which may be Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, or a mixture thereof. Consumers often find such non-commensal bacteria unnecessary or undesirable, as they may provide certain negative characteristics such as itching, discomfort, or foul odor. In certain cases, for example, in dry skin, dermatitis, and atopic dermatitis, they may be even more harmful, or in extreme cases, pathogenic.

[0022] In one aspect, the composition of the present invention is preferably a wash-off composition, which is enabled by containing 1 to 80% by weight of a surfactant. Generally, the surfactant can be selected from surfactants described in known textbooks such as "Surface Active Agents" Vol. 1 by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, and / or the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company, or in "Tenside Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Any type of surfactant, i.e., anionic, cationic, non-ionic, zwitterionic or amphoteric surfactant, can be used, but preferred surfactants are anionic or non-ionic type surfactants.

[0023] The pH of the wash-off composition according to the present invention is within the range from 4 to 11, preferably within the range from 5.5 to 10.

[0024] The surfactant can be a soap. Soap is a surfactant suitable for the application of personal cleansing of the composition of the present invention. The soap is preferably a C8 - C24 soap, more preferably a C10 - C20 soap and most preferably a C12 - C16 soap. The soap can or cannot have one or more carbon-carbon double bonds or triple bonds. The cation of the soap can be an alkali metal, an alkaline earth metal or ammonium. Preferably, the cation of the soap is selected from sodium, potassium or ammonium. More preferably, the cation of the soap is sodium or potassium.

[0025] Soap can be obtained by saponifying fats and / or fatty acids. Fats or oils commonly used in soap production may include, for example, animal fat, animal fat stearin, palm oil, palm stearin, soybean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process, fatty acids are derived from oils / fats selected from coconut, rice bran, peanuts, animal fat, palm, palm kernel, cottonseed, soybeans, castor, etc.

[0026] A typical fatty acid mixture consists of 5 to 30% coconut fatty acids and 70 to 95% fatty acids from hydrogenated rice bran oil. Other suitable oils / fats, such as fatty acids derived from peanuts, soybeans, animal fats, palm, palm kernels, etc., may also be used in other desirable proportions. The most preferred soap is laurate soap. When soap is present in the solid form of the present invention, it is present in amounts from 30 to 90% by weight, preferably from 50 to 85% by weight, and more preferably from 55 to 75% by weight of the composition. When soap is present in the liquid form of the composition, it is present in amounts from 0.5 to 20% by weight, preferably from 1 to 10% by weight of the composition.

[0027] Alternatively, the surfactant may be a nonionic surfactant, such as a C8-C22, preferably C8-C16 fatty alcohol ethoxylate containing an ethylene oxide between 1 and 8. The surfactant is preferably selected from primary alkyl sulfates, secondary alkyl sulfonates, alkylbenzene sulfonates, or ethoxylated alkyl sulfates. The composition may further contain an anionic surfactant, such as an alkyl ether sulfate, preferably an alkyl ether sulfate having an ethylene oxide group between 1 and 3 and / or a sulfonic acid, preferably from either a natural or synthetic source. Particularly preferred is sodium lauryl ether sulfate. Alkyl polyglucosides may also be present in the composition, preferably having a carbon chain length between C6 and C16. The appropriate concentration of the surfactant in liquid form applied to washing is generally more than 0.5% by weight but less than 10% by weight of the composition, preferably between 1 and 5% by weight. In solid compositions, the surfactant is preferably present in an amount of 5 to 40% by weight, preferably between 10 and 30% by weight of the composition.

[0028] Water may preferably be present in an amount of 10 to 90% by weight of the composition, depending on the form of the composition. In solid compositions, water may be present in an amount of 10 to 30%, while in liquid or semi-solid compositions, water may be present in an amount of 40 to 90%.

[0029] If the composition according to another aspect of the present invention is a leave-on composition, it preferably comprises one or more surfactants, emollients, wetting agents, dyes, or preservatives.

[0030] The pH of the leave-on composition according to the present invention is in the range of 5 to 9, preferably in the range of 5.5 to 8.

[0031] The carrier acts as a diluent or dispersant for the components of the composition. The carrier can be aqueous, anhydrous, or an emulsion, with water-in-oil or oil-in-water emulsions generally preferred. If the use of water is desired, it typically balances the composition, most preferably in an amount of 40 to 80% by weight.

[0032] In addition to water, organic solvents may be optionally included as carriers to support any other carriers in the composition of the present invention. Examples include alkanols such as ethyl and isopropyl alcohols.

[0033] Other suitable organic solvents include ester oils such as isopropyl myristate, cetyl myristate, 2-octyldodecyl myristate, avocado oil, almond oil, olive oil, and neopentyl glycol dicaprate. Typically, such ester oils help to emulsify the composition, and effective amounts are often used to produce a stable, and most preferably, water-in-oil emulsion.

[0034] Emollients can also be used as carriers, if desired. Alcohols such as 1-hexadecanol (i.e., cetyl alcohol) are preferred. Other emollients include silicone oils and synthetic esters. Suitable silicone oils for use include cyclic or linear polydimethylsiloxanes containing 3 to 9, preferably 4 to 5, silicon atoms. Non-volatile silicone oils useful as emollients include copolymers of polyalkylsiloxanes, polyalkylallylsiloxanes, and polyethersiloxanes. Non-volatile polyalkylsiloxanes are useful as polydimethylsiloxanes. Silicone elastomers can also be used. Optional ester emollients include: (i) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples include isoarachidyl neopentanoate, isononyl isonanoate, oleyl myristate, oleyl stearate, and oleyl oleate; (ii) ether esters, for example, fatty acid esters of ethoxylated fatty alcohols; (iii) Polyhydric alcohol esters. Satisfactory polyhydric alcohol esters include ethylene glycol mono and di fatty acid esters, diethylene glycol mono and di fatty acid esters, polyethylene glycol (200-6000) mono and di fatty acid esters, propylene glycol mono and di fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono and di fatty acid esters, polyglycerol polyfatty acid esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; (iv) wax esters, such as beeswax, whale wax, stearyl stearate and arachidyl behenate; and (v) Sterol esters and cholesterol fatty acid esters are examples of this. That is the case.

[0035] If present, emollients typically constitute 0.1 to 50% by mass of the composition, encompassing the entire range included therein.

[0036] Fatty acids having 10 to 30 carbon atoms can also be included as carriers. Examples of such fatty acids include pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, arachidic acid, behenic acid or erucic acid and mixtures thereof.

[0037] Moisture retention can be improved through the use of petrolatum or paraffin. Thickeners can also be used as part of the carrier in the composition. Typical thickeners include cross-linked acrylates (e.g., Carbopol® 982), hydrophobically modified acrylates (e.g., Carbopol® 1382), cellulose derivatives, and natural gums. Useful cellulose derivatives include sodium carboxymethylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, ethylcellulose, and hydroxymethylcellulose. Natural gums suitable for the present invention include guar, xanthan gum, sclerotia particles, carrageenan, pectin, and combinations of these gums. The amount of thickener can range from 0.001 to 5, optionally from 0.01 to 0.5% by weight of the composition.

[0038] Surfactants may also be present. If present, the total amount of surfactant is 2 to 40% by weight, preferably 4 to 20% by weight, and optionally 5 to 12% by weight of the composition. Surfactants are selected from the group consisting of anionic, nonionic, cationic, and amphoteric active substances. Particularly preferred nonionic surfactants are those condensed with 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobic substance, C 10~20 These include those having hydrophobic substances of fatty alcohols or fatty acids; mono and di fatty acid esters of ethylene glycol; fatty acid monoglycerides; sorbitan, mono and di C8-C20 fatty acids; block copolymers (ethylene oxide / propylene oxide); and polyoxyethylene sorbitan and combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g., methyl gluconamide) are also suitable nonionic surfactants.

[0039] Preferred anionic surfactants include soap, alkyl ether sulfates and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, and C 8から20Acyl isethionate, acyl glutamate, C 8から20 This includes alkyl ether phosphates and combinations thereof.

[0040] A variety of other components can also be used in the composition. Active substances are defined as skin beneficiaries other than emollients and components that merely improve the physical properties of the composition. Common examples, though not limited to this category, include body pigments, such as talc and silica, as well as α-hydroxy acids, β-hydroxy acids, and zinc salts.

[0041] Beta-hydroxy acids include salicylic acid. Zinc oxide and zinc pyrithione are examples of useful zinc salts.

[0042] Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionates, and various quaternary ammonium compounds. Particularly preferred preservatives are methylparaben, propylparaben, phenoxyethanol, and benzyl alcohol. The preservative is present in an amount of 0.1 to 2% by weight of the composition.

[0043] Packaging can be patches, bottles, tubes, roll ball applicators, high-pressure gas-driven aerosol devices, compression containers, or bottles with lids.

[0044] Without being constrained by theory, the inventors believe that while many bacteria can synthesize most amino acids using their internal mechanisms, they cannot synthesize all of them. If they lack the necessary enzymes, they need to be supplied with amino acids from their environment. Furthermore, they always prefer to use amino acids already available in their environment rather than synthesize them, because producing amino acids requires energy. In the current scenario, we identified a mixture of essential amino acids needed to support the good growth of symbiotic bacteria, but coincidentally, they also offered no benefit whatsoever to pathogenic bacteria.

[0045] The present invention is therefore intended to increase, promote, improve, maintain, or sustain skin health and skin resilience. This is achieved by ensuring a healthy skin ecosystem through a balanced microbiome. A balanced microbiome means that the ratio of symbiotic bacteria to non-symbiotic bacteria is maintained within a desirable range for skin health that should be maintained.

[0046] The present invention is particularly useful for use on the skin of infants, where the use of a wide range of antimicrobial agents is considered too irritating. This is because such use tends to hinder the growth and maintenance of a healthy skin microbiome for the long-term health of the infant as they grow into adulthood. Therefore, whether or not they are used on the skin of infants or others, the compositions for use in the present invention are substantially free of conventional antimicrobial compounds. Substantially free means that conventional antimicrobial active substances are present in amounts of less than 0.1% by mass, more preferably less than 0.05% by mass, even more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass of the composition. Conventional antimicrobial active substances mean antimicrobial active substances that kill or inhibit bacteria that attack the skin, such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Preservatives included in the composition for microbial stability are excluded from the above definition of antimicrobial active substances. Preservatives are included to ensure that the composition is stable with respect to microorganisms that may grow and degrade the composition. On the other hand, antimicrobial compounds are included in the composition to inhibit the growth of microorganisms present on the substance to which the composition is applied (e.g., skin).

[0047] Conventional antimicrobial compounds are generally compounds derived from biguanides, bisphenols, halophenols, trace metal compounds such as silver or zinc compounds, cationic antimicrobial compounds, or essential oil active substances. Biguanides have a common base structure that can be further derivatized (e.g., chlorhexidine or polyhexamethylene biguanide (PHMB)). Bisphenols include triclosan or hexachlorophene. Halophenols include chloroxylenol (PCMX). Cationic compounds are another type of antimicrobial active substance, such as benzalkonium chloride, cetylpyridinium chloride, or cetyltrimethylammonium bromide.

[0048] Low-boiling point alcohols (fast-acting antimicrobial agents) are not particularly present in substantial amounts in the compositions of the present invention. Ideally, they are not present in such compositions. Low-boiling point alcohols refer to monohydric alcohols having 2 to 5 carbon atoms.

[0049] When the composition of the present invention is formulated for use on the skin of an infant, it is preferable that it is substantially free of fragrance components. Fragrance components mean molecules or groups of molecules that make up a perfume. A characteristic of such a composition is that they are volatile (at various temperatures) and provide a pleasant fragrance. In the context of perfume or fragrance components, "by substantially free" means that they are present in amounts of less than 0.05% by mass, more preferably less than 0.01% by mass, even more preferably less than 0.005% by mass, and even more preferably less than 0.001% by mass of the composition.

[0050] Furthermore, another aspect of the present invention relates to compositions of the present invention for use in protecting the skin from non-symbiotic, and even undesirable, bacteria by nourishing skin commensal bacteria. While the uses according to the present invention are generally of a non-therapeutic nature, the compositions can also be used in therapeutic applications. Therefore, the compositions are preferably compositions for use in therapeutically protecting the skin from harmful bacteria by nourishing skin commensal bacteria. In another aspect, the present invention relates to the use of compositions comprising a combination of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid, L-tyrosine, L-glycine and L-threonine for providing the skin with the benefits of the microbiome, wherein the compositions contain less than 0.05% by mass, preferably less than 0.01% by mass, of other amino acids.

[0051] Furthermore, another aspect of the present invention relates to a method for nourishing skin commensal bacteria while inhibiting the growth of harmful bacteria, comprising the step of applying the composition of the present invention to the skin. They observed this through experimental data for Staphylococcus epidermidis, a skin commensal bacterium, but it is likely possible with numerous other such beneficial bacteria known to colonize healthy skin. The method of the present invention is effective in inhibiting harmful bacteria, including one or more selected from Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, or a mixture thereof.

[0052] The present invention will be demonstrated by the following unlimited embodiments. [Examples]

[0053] Example 1: Growth of Staphylococcus epidermidis in the presence of a single amino acid as a nutritional supplement: The growth of the above-mentioned symbiotic bacteria due to the separate presence of each of the 20 different amino acids was studied. All 20 L-amino acids were sourced from Hi-Media. The stocks were prepared in distilled water and filtered sterilized by passing them through a 0.22 μm filter. 100 mM sodium phosphate buffer pH 7.4 was prepared and filtered sterilized. The reaction was set up in a 96-well flat-bottomed transparent plate. 100 μl of 20% TSB (prepared by diluting 100% TSB with 100 mM sodium phosphate buffer) was added to each well, followed by 20 μl of 10% glucose (prepared in water and filtered sterilized), 20 μl of 1% individual amino acid stock (in the control wells, the same volume of buffer was added instead of the amino acid stock), and 10% of the stock prepared in 100 mM sodium phosphate buffer. 8 20 μl of 0.2 OD equivalent to CFU / ml 600nm A Staphylococcus epidermidis culture (plate cultured for 22-24 hours) was added, and the final volume was 200 μl with buffer. The final concentration of individual amino acids was 0.1%. Each reaction was set up in three replicates. The plates were incubated at 37°C under steady-state conditions for 24 hours. After 24 hours, the absorbance of the plates was measured at 600 nm using a TECAN plate reader. The absorbance values ​​were then normalized to the control (Staphylococcus epidermidis grown in 10% TSB + 1% glucose). Data for the growth percentage of each sample relative to the control are summarized in Table 1 below:

[0054] [Table 2]

[0055] The samples in the table above with higher absolute values ​​can be interpreted as amino acids that ensure higher growth of Staphylococcus epidermidis, a commensal bacterium of the skin.

[0056] Example 2: Growth of Staphylococcus epidermidis in the presence of a 0.2% amino acid mixture (containing all 20 amino acids with single amino acid deficiency) Mixtures of 20 different amino acids were prepared by mixing all of each amino acid stock in equal proportions, with one amino acid excluded from each mixture (equal volumes of water were added in place of the excluded amino acid). The control amino acid mixture was prepared by mixing all of the 20 amino acid stocks in equal proportions.

[0057] The reaction was set up in a 96-well flat-bottom clear plate. 100 μl of 20% TSB (prepared by diluting 100% TSB with 100 mM sodium phosphate buffer) was added to each well, followed by 20 μl of 10% glucose (prepared in water and filter-sterilized), 20 μl of 2% amino acid mixture, and 100 mM sodium phosphate buffer prepared at pH 7.4. 8 20 μl of 0.2 OD equivalent to CFU / ml 600nm A culture of Staphylococcus epidermidis (plate cultured for 22-24 hours) was added, and the final volume was 200 μl with buffer. Each reaction was set up in three replicates. The final concentration of each amino acid in the mixture was 0.01%.

[0058] The plates were incubated at 37°C under steady-state conditions for 24 hours. After 24 hours, the absorbance of the plates was measured at 600 nm using a TECAN plate reader. The absorbance values ​​were then normalized to a control (Staphylococcus epidermidis grown in a 0.2% amino acid mixture containing 10% TSB + 1% glucose + all 20 amino acids).

[0059] The growth percentage data for each control sample is summarized in Table 2 below. The amino acids shown in each of the following columns indicate those not present in that particular sample:

[0060] [Table 3]

[0061] Samples in the table above with lower absolute values ​​can be interpreted as amino acids that ensure higher growth of Staphylococcus epidermidis, a commensal bacterium of the skin. Therefore, lower values ​​are better.

[0062] Based on the data (and the differences between them) in Tables 1 and 2 above, the inventors have shortlisted seven amino acids, namely L-cysteine, L-serine, L-alanine, L-aspartic acid, L-tyrosine, L-glycine, and L-threonine, as the amino acids most likely to ensure the growth of Staphylococcus epidermidis.

[0063] Example 3: Growth patterns of Staphylococcus epidermidis / Staphylococcus aureus in the presence of the above seven amino acid mixture Growth dynamics experiments were conducted on both Staphylococcus epidermidis (symbiotic) and Staphylococcus aureus (pathogenic) in the presence of an amino acid mixture (mixture 7) prepared using a set of seven amino acids (alanine, aspartic acid, cysteine, glycine, serine, tyrosine, and threonine) that were shown in supplemental experiments to boost the growth of Staphylococcus epidermidis. The growth dynamics of the two microorganisms described above, measured as absorbance at 600 nm, are shown in Table 3 below.

[0064] [Table 4]

[0065] The data in the table above shows that a mixture of seven selected amino acids begins to reduce the growth of Staphylococcus aureus after 18 hours, while ensuring the continued growth of Staphylococcus epidermidis even after 18 hours.

[0066] Example 4: Identification of the five most effective amino acids from seven selected amino acids that inhibit the growth of Staphylococcus aureus. To identify the set of amino acids that primarily contribute to the higher growth rate of Staphylococcus aureus in mixture 7, growth kinetics experiments were conducted for all seven individual amino acids. The kinetic data showed a steady increase for all seven amino acids, followed by a plateau in growth. Experiments were conducted for growth up to 20 hours. These were performed at a concentration of 0.1% by mass of each individual amino acid. Absorbance data at 600 nm are summarized in Table 4 below:

[0067] [Table 5]

[0068] The data in Table 4 above shows that the first five amino acids, namely cysteine, serine, alanine, aspartic acid, and tyrosine, are desirable and ensure maximum inhibition of Staphylococcus aureus.

[0069] Example 5: Growth patterns of Staphylococcus epidermidis / Staphylococcus aureus in the presence of a mixture of five selected amino acids Growth dynamics experiments were conducted on both Staphylococcus epidermidis and Staphylococcus aureus in the presence of an amino acid mixture (mixture 5) prepared using the set of five selected amino acids (alanine, aspartic acid, cysteine, serine, and tyrosine) identified in the above experiments. The growth dynamics of the two microorganisms, measured as absorbance at 600 nm, are shown in Table 5 below.

[0070] [Table 6]

[0071] The data in the table above shows that a mixture of five selected amino acids ensures the continuous growth of Staphylococcus epidermidis while significantly reducing the growth of Staphylococcus aureus. Thus, the desirable behavior of the microbiome balance is significantly observed with this mixture of five amino acids.

[0072] Example 6: Growth pattern of Staphylococcus epidermidis / Staphylococcus aureus in the presence of a smaller subset of mixture 5 To further optimize and minimize the amino acid mixtures from a selection of five amino acid mixtures that preferentially support the growth of Staphylococcus epidermidis over Staphylococcus aureus, growth dynamics experiments were conducted on both Staphylococcus epidermidis and Staphylococcus aureus in the presence of different amino acid combinations containing two, three, or four amino acids, all of which retain two key amino acids, namely cysteine ​​and serine, in common across all combinations tested. These two were selected because, as can be seen in Table 2, their individual absence resulted in the lowest growth among the diverse amino acid combinations. The data are summarized in Table 6 below:

[0073] [Table 7]

[0074] The data in Table 6 above show that the smallest subset that yields the desired results, namely higher growth of Staphylococcus epidermidis and lower growth of Staphylococcus aureus, is mixture 3a, which is a combination of cysteine, serine, and alanine.

[0075] Example 7: Growth patterns of Staphylococcus epidermidis / Staphylococcus aureus in the presence of a mixture of three selected amino acids Growth dynamics experiments were performed on both Staphylococcus epidermidis and Staphylococcus aureus in the presence of an amino acid mixture (mixture 3a) prepared using the set of three selected amino acids (alanine, cysteine, and serine) identified in the above experiments. The growth dynamics of the two microorganisms, measured as absorbance at 600 nm, are shown in Table 7 below.

[0076] [Table 8]

[0077] The data in the table above shows that a mixture of three selected amino acids ensures the continuous growth of Staphylococcus epidermidis while significantly reducing the growth of Staphylococcus aureus. Thus, a significant microbiome balance is observed with this optimized mixture of three amino acids.

Claims

1. A personal care composition for use as a prebiotic for skin symbiotic bacteria, wherein the composition comprises all of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid and L-tyrosine, each of which is present in an amount of 0.01 to 1% by weight, and the total amount of other amino acids is less than 0.005% by weight.

2. A personal care composition for use as a prebiotic for skin symbiotic bacteria, wherein the composition comprises all of the amino acids L-cysteine, L-serine and L-alanine, each of which is present in an amount of 0.01 to 1% by weight, and the total amount of other amino acids is less than 0.005% by weight.

3. The composition according to claim 1 or 2, comprising amino acids in a total amount of 0.07 to 7% by weight.

4. The composition according to any one of claims 1 to 3, comprising less than 1% by weight of a peptide having more than 3 amino acids in its chain.

5. A composition according to any one of claims 1 to 4, comprising less than 1% by weight of protein.

6. A composition according to any one of claims 1 to 5 for use in a method of nourishing skin symbiotic bacteria.

7. The composition according to claim 6, wherein the skin symbiotic bacteria is Staphylococcus epidermidis.

8. A composition according to any one of claims 1 to 5 for use in a method of nourishing skin commensal bacteria while inhibiting the growth of harmful bacteria.

9. The composition according to claim 8, wherein the harmful bacteria include Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, or a mixture thereof.

10. A composition for providing the benefits of the microbiome to the skin, wherein the composition comprises all of the amino acids L-cysteine, L-serine, L-alanine, L-aspartic acid and L-tyrosine, with each of the amino acids present in an amount of 0.01 to 1% by weight, and the total amount of other amino acids being less than 0.005% by weight.

Images