Methods for inhibiting the growth of Malassezia restricta

Abstract

The present invention relates to the use of glycine or a composition comprising glycine in inhibiting the growth of Malassezia restricta when applied to external surfaces of the human body, the composition comprising at least 0.04% glycine by weight of the composition. The present invention also relates to the use of glycine or a composition comprising glycine in balancing the microbiome on a surface (balancing means selectively reducing the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), the composition comprising at least 0.04% glycine by weight of the composition.

Description

[Technical Field]

[0001] The present invention relates to a method for balancing the microbiome on an external surface of the human body, preferably on human skin or scalp, more preferably on the scalp. In particular, the present invention relates to the use of glycine or a composition comprising glycine to inhibit the growth of harmful microorganisms, such as Malassezia restricta. The present invention also relates to the use of glycine or a composition comprising glycine to balance the microbiome on an external surface of the human body. [Background technology]

[0002] Microorganisms such as bacteria, fungi, viruses, protozoa, and mites are often found to reside on surfaces such as fabrics, hard surfaces, and skin. The surface microbiome refers to the entire population of microorganisms present on a surface. While some of the microorganisms present on a surface may be considered beneficial, other microorganisms that coexist with the good microorganisms may be harmful in nature.

[0003] The scalp microbiome has recently received attention for its potential causative role in the development of dandruff. The main fungal / bacterial species present on the scalp are Malassezia restricta, Malassezia globosa, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus capitis. Malassezia restricta, a lipid-soluble yeast, is known to be associated with dandruff. Antifungal agents such as zinc pyrithione, piroctone olamine, and selenium sulfide have been demonstrated to be effective antidandruff agents by reducing the growth of Malassezia on the scalp. Staphylococcus and Cutibacterium are the most abundant bacterial genera in both healthy and dandruff-affected scalps. However, at the species level, Staphylococcus capitis has been reported to be positively associated with dandruff status, while Staphylococcus epidermidis and Cutibacterium acnes are considered to be commensal bacteria positively associated with dandruff-free scalp status in terms of relative or absolute abundance. Summary of the Invention

[0004] Antimicrobial compositions are commonly used by individuals to eliminate or reduce harmful microorganisms, however, the use of broad-spectrum antimicrobial compositions such as zinc pyrithione may also kill or inhibit beneficial microorganisms.

[0005] There remains a need for treatments that can balance the microbiome by selectively reducing the number of harmful microorganisms while either limiting or selectively increasing the number of beneficial microorganisms.

[0006] The present inventors have surprisingly found that application of glycine or a composition containing certain levels of glycine to the external surfaces of the human body can inhibit the growth of Malassezia restricta, but has no inhibitory effect whatsoever on resident microorganisms selected from Staphylococcus epidermidis and Cutibacterium acnes.

[0007] In a first aspect, the present invention relates to the use of glycine or a composition comprising glycine in inhibiting the growth of Malassezia restricta when applied to the external surface of the human body, the composition comprising at least 0.04% glycine by weight of the composition.

[0008] In a second aspect, the present invention relates to the use of glycine or a composition comprising glycine in balancing the microbiome (balancing meaning selectively reducing the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes) on the external surfaces of the human body, said composition comprising at least 0.04% glycine by weight of the composition.

[0009] In a third aspect, the present invention relates to a method of applying glycine or a composition comprising glycine to an external surface of the human body to inhibit Malassezia restricta, wherein the composition comprises at least 0.04% glycine by weight of the composition.

[0010] In a fourth aspect, the present invention relates to a method for balancing the microbiome (by balancing, it is meant to selectively reduce the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of commensal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes) by applying glycine or a composition comprising glycine to the external surface of the human body, wherein the composition comprises at least 0.04% glycine by weight of the composition.

[0011] In a fifth aspect, the present invention relates to a method of applying glycine or a composition comprising glycine to an external surface of the human body to protect the surface from harmful microorganisms that are Malassezia restricta while ensuring the growth of resident bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes, wherein the composition comprises at least 0.04% glycine by weight of the composition.

[0012] In a sixth aspect, the present invention relates to glycine or a composition comprising glycine for use in inhibiting the growth of Malassezia restricta, the composition comprising at least 0.04% glycine by weight of the composition.

[0013] In a seventh aspect, the present invention relates to glycine or a composition comprising glycine for use in balancing the microbiome on the external surface of the human body (by balancing, it is meant to selectively reduce the number of harmful microorganisms which are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), wherein the composition comprises at least 0.04% glycine by weight of the composition.

[0014] All other aspects of the present invention will become more readily apparent in light of the following detailed description and examples. DETAILED DESCRIPTION OF THE INVENTION

[0015] For the avoidance of doubt, any feature of one aspect of the present invention can be utilized in any other aspect of the present invention. The term "comprising" is intended to mean "including," but not necessarily "consisting of" or "composed of." In other words, the steps or options described need not be all-inclusive. It should be noted that the examples described below are intended to clarify the invention and are not intended to limit the invention to those examples themselves. Similarly, unless otherwise indicated, all percentages are weight / weight percent. Except in the examples and comparative examples, or unless explicitly stated, all numbers in this Detailed Description and Claims describing amounts of materials or reaction conditions, physical properties of materials, and / or uses are to be understood as modified by the word "about." Numerical ranges expressed in the format "from x to y" are understood to include both x and y. When multiple preferred ranges for a particular feature are described in the format "from x to y," it is understood that all ranges combining the different endpoints are also contemplated. As used herein, the indefinite article "a" or "an" and its corresponding definite article "the" mean at least one or more than one, unless otherwise specified. Various features of the invention referred to in individual sections above apply mutatis mutandis to other sections, where appropriate. Thus, features specified in one section may, where appropriate, be combined with features specified in other sections. Section headings are provided for convenience only and are not intended to limit the disclosure in any way.

[0016] As used herein, the term "hair care composition" is meant to include compositions for topical application to mammalian, particularly human, hair and / or scalp. Such compositions can generally be classified as leave-on or rinse-off and include any product applied to the human body to improve appearance, cleansing, odor control, or general aesthetics. The compositions of the present invention may be in the form of a liquid, lotion, cream, foam, scrub, gel, or bar. Non-limiting examples of such compositions include leave-on hair lotions, creams, and rinse-off shampoos, conditioners, shower gels, or toilet bars.

[0017] microorganisms Microorganisms can be described as small living organisms such as bacteria, fungi, viruses, protozoa, or mites. The microbiome on a surface collectively refers to all the microorganisms on a surface. In other words, the microbiome is a community of microorganisms.

[0018] As used herein, the term "balancing the microbiome" means selectively removing / killing / reducing microorganisms present on a surface that are considered harmful, while maintaining substantially the same level of or increasing the number of microorganisms that are considered beneficial.

[0019] The potentially harmful microorganism is Malassezia restricta (M. restricta), a lipophilic yeast and one of the most abundant Malassezia species in the human skin microbiome. M. restricta is considered an opportunistic pathogen associated with skin disorders such as seborrheic dermatitis and dandruff.

[0020] At least one potentially beneficial microorganism is Staphylococcus epidermidis (S. epidermidis). S. epidermidis has been reported as a beneficial bacterium involved in maintaining skin health. It is a common microorganism that is likely involved in competitive exclusion of pathogens. It is therefore an indicator of the state of the surface microbiome. The growth and maintenance of S. epidermidis is an important means of maintaining a healthy microbiome.

[0021] At least one microorganism thought to be beneficial is Cutibacterium acnes (C. acnes), which is one of the major bacterial species identified on healthy scalps.

[0022] The present invention relates to the use of glycine or a composition containing glycine in inhibiting the growth of Malassezia restricta when applied to an external surface of the human body. However, such use has no inhibitory effect on the growth of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes. The surface is preferably human skin, such as a surface of the hands, face, body, or scalp. More preferably, the surface is the scalp.

[0023] The balancing of the microbiome is achieved by selectively reducing the number of harmful microorganisms, namely Malassezia restricta, without having any effect on the number of resident bacteria selected from S. epidermidis and C. acnes.

[0024] The present invention relates to the use of glycine or a composition comprising glycine in balancing the microbiome on an external surface of the human body, preferably a surface such as human skin, e.g., a surface of the hand, face, body, or scalp. More preferably, the surface is the scalp.

[0025] It has also been surprisingly found that the use of glycine or a composition according to the present invention does not significantly affect the growth of other microorganisms of the genus Malassezia, such as Malassezia furfur. The use of glycine or a composition according to the present invention has no effect whatsoever on inhibiting the growth of Malassezia furfur.

[0026] glycine Glycine is an amino acid essential for the production of collagen, a protein that provides structure to bones, skin, muscles, and connective tissue. Glycine is the simplest and most stable amino acid and has the chemical formula NH2-CH2-COOH.

[0027] Amino acids are typically considered a source of nutrition for both microorganisms and humans. Surprisingly, it has been found that glycine or compositions containing glycine at specific levels can inhibit the growth of Malassezia restricta when applied to surfaces. However, such use has no inhibitory effect on the growth of commensal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes. Therefore, such use can balance the microbiome, selectively reducing the number of harmful microorganisms, such as Malassezia restricta, while having no effect on the number of commensal bacteria selected from S. epidermidis and C. acnes.

[0028] The compositions of the present invention comprise at least 0.04% glycine, preferably at least 0.1% glycine, more preferably at least 0.15% glycine, by weight of the composition.

[0029] Preferably, the composition comprises 0.04 to 10% glycine by weight of the total composition, preferably 0.1% to 5% glycine by weight, more preferably 0.15 to 2% by weight, even more preferably 0.2 to 2% by weight glycine, and all ranges therein inclusive.

[0030] In compositions intended to be diluted before application, the preferred minimum concentration of glycine may be higher. It is generally preferred that the concentration of glycine in the composition used according to the present invention be equal to or greater than the optimal concentration in the working composition, since in many typical applications the composition will be used pure or diluted to form the working composition. For example, when washing hands with water and a composition of the present invention, the foam produced is typically a 50% by weight dilution of the original composition. Similarly, for hair washes and body washes, liquid or bar soaps are typically diluted with water to about 8% to 10% by weight, which corresponds to about a 10-fold dilution of the product. Therefore, the concentration of glycine in the composition is preferably such that when the composition is diluted or dissolved in a suitable medium before or during use, the concentration in the diluted or dissolved mixture is sufficient to provide a microbiome-balancing effect on the external surfaces of the human body.

[0031] composition The composition is preferably a personal care composition. A personal care composition is a composition for treating, cleaning, caring for, or conditioning a person. The foregoing includes, but is not limited to, chemicals, compositions, products, or combinations thereof related to or having utility or use in treating, cleansing, or conditioning a person (including, inter alia, the skin, hair, scalp, and oral cavity), and all of the foregoing products. Examples of personal care compositions include, but are not limited to, leave-on skin lotions and creams, shampoos, conditioners, shower gels, bar soaps, antiperspirants, deodorants, shaving creams, depilatories, lipsticks, foundations, mascaras, sunscreens, or sunscreen lotions. Preferably, the composition is a leave-on personal care composition.

[0032] Preferred personal care compositions for use in the present invention include rinse-off or leave-on hair or scalp care compositions such as shampoos, conditioners, creams, lotions, gels, serums, mousses, or oils. Leave-on hair or scalp care compositions such as lotions, serums, and oils intended for topical application to the hair or scalp are preferred.

[0033] Compositions for use in the present invention generally include a cosmetically acceptable carrier, the term "cosmetically acceptable" meaning that the carrier is suitable for topical application to the skin, has good aesthetic properties, is compatible with other ingredients, and does not raise safety or toxicity concerns.

[0034] The carrier may be composed of an aqueous phase, an oil phase, an alcohol phase, a silicone phase, or mixtures thereof, and may be in the form of an emulsion, which may have a wide range of consistencies, including thin lotions (which may also be suitable for spray or aerosol delivery), creamy lotions, light creams, and heavy creams.

[0035] Compositions for use in the present invention can also be formulated in a single-phase carrier, such as a hydrophobic or hydrophilic liquid. Suitable hydrophobic liquid carriers include liquid polyorganosiloxanes, mineral oil, hydrogenated polyisobutene, polydecene, paraffins and isoparaffins containing at least 10 carbon atoms, aliphatic or aromatic ester oils (e.g., isopropyl myristate, lauryl myristate, isopropyl palmitate, diisopropyl sebacate, diisopropyl adipate, C12-C15 alkyl benzoates), polyglycol ethers (e.g., polyglycol butanol ethers), and mixtures thereof. Suitable hydrophilic liquid carriers include water, monohydric or polyhydric aliphatic alcohols having 2 to 8, preferably 2 or 3, carbon atoms (e.g., ethanol and isopropanol), oligoglycol ethers having 2 to 5 repeating units (e.g., dipropylene glycol), and mixtures thereof. A particularly preferred carrier is water.

[0036] Liquid compositions for use in the present invention may be thickened using, for example, one or more water-soluble or colloidal water-soluble polymeric thickeners.

[0037] Compositions for use in the present invention preferably include a thickening agent.

[0038] Suitable water-soluble or colloidal water-soluble polymeric thickeners include hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, polyquaternium-10, carrageenan, guar gum, hydroxypropyl guar gum, xanthan gum, polyvinyl alcohol, acrylic acid / ethyl acrylate copolymers, carboxyvinyl polymers, crosslinked polyacrylate polymers, and polyacrylamide polymers.

[0039] The composition for use in the present invention may further comprise a conditioning agent that provides a conditioning benefit. Preferably, the composition comprises discretely dispersed droplets of a water-insoluble conditioning agent having an average droplet size (D3,2) of less than 15 microns, preferably less than 10 microns, more preferably less than 5 microns, and most preferably less than 3 microns. The average droplet size (D3,2) of the water-insoluble conditioning agent can be measured by laser light scattering techniques, for example, using a Malvern Instruments 2600D particle size analyzer.

[0040] The water-insoluble conditioning agent may include a non-silicone conditioning agent, which comprises a non-silicone oily or fatty material such as hydrocarbon oils, fatty esters, and mixtures thereof. Preferably, the water-insoluble conditioning agent is an emulsified silicone oil.

[0041] Suitable silicones include polydiorganosiloxanes, particularly polydimethylsiloxanes with the CTFA designation dimethicone. Suitable for use in the compositions of the present invention (particularly shampoos and conditioners) are polydimethylsiloxanes with hydroxyl end groups that have the CTFA designation dimethiconol. Also suitable for use in the compositions of the present invention are silicone gums with slight crosslinking, such as those described in WO 96 / 31188. Preferably, the silicone oil comprises dimethicone, dimethiconol, or a mixture thereof.

[0042] Suitable emulsified silicones for use in the compositions of the present invention are available as preformed silicone emulsions from silicone suppliers such as Dow Corning and GE silicones. The use of such preformed silicone emulsions is preferred for ease of processing and control of silicone particle size. Such preformed silicone emulsions typically further contain a suitable emulsifier and can be prepared by a chemical emulsification process such as emulsion polymerization or by mechanical emulsification using a high-shear mixer. Examples of suitable preformed silicone emulsions include DC1785, DC1788, and DC7128, all available from Dow Corning. These are dimethiconol / dimethicone emulsions.

[0043] Another type of silicone that can be used is a functionalized silicone, such as an amino-functional silicone, which means a silicone containing at least one primary, secondary, tertiary amine group, or quaternary ammonium group. Examples of suitable amino-functional silicones include polysiloxanes having the CTFA designation "amodimethicone."

[0044] The water-insoluble conditioning agent will typically be present in compositions for use in the present invention in an amount of from 0.05 to 15%, preferably from 0.1 to 10%, more preferably from 0.5 to 8%, and most preferably from 1 to 5%, based on the total weight of the composition.

[0045] The pH of the composition used according to the present invention is preferably 4.0 or higher, more preferably in the range of 5.0 to 10.0.

[0046] Oils and lotions for use in the present invention typically have an oil phase containing one or more cosmetically acceptable fatty substances which may be liquid or solid at room temperature (25° C.) Lotions are typically aqueous emulsions having an aqueous phase in addition to the oil phase.

[0047] Suitable cosmetically acceptable fatty substances include naturally occurring oils (e.g., sunflower oil, borage oil, soybean oil, castor oil, olive oil and almond oil); esters of monoalcohols or polyols with monocarboxylic or polycarboxylic acids, alcohols and / or acids containing at least one hydrocarbon chain containing at least 6 carbon atoms (e.g., octyl palmitate, isopropyl myristate, isopropyl palmitate, isopropyl isostearate, hexyl laurate, syl, isohexyl laurate, isohexyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate, decyl stearate, dihexyldecyl adipate, lauryl lactate, myristyl lactate, cetyl lactate, oleyl stearate, oleyl oleate, oleyl myristate, lauryl acetate, cetyl propionate, isononyl isononanoate, propylene glycol dicaprate, diisopropyl adipate, dibutyl adipate, and oleyl adipate; ethers ( For example, dicapryl ether; fatty alcohols (for example, cetyl alcohol, stearyl alcohol, and behenyl alcohol); isoparaffins (for example, isooctane, isododecane, and isohexadecane); silicone oils (for example, cyclomethicone, dimethicone, and dimethiconol); hydrocarbon oils (for example, mineral oil, petrolatum, and polyisobutene); fatty acids containing 8 to 30 carbon atoms (for example, stearic acid, lauric acid, palmitic acid, and oleic acid); vegetable fats (for example, cocoa butter, coconut oil, palm oil, and shea butter); petroleum-based, natural, and synthetic waxes (e.g., lanolin wax, beeswax, carnauba wax, candelilla wax, paraffin wax, lignite wax, microcrystalline wax, ceresin, ozokerite, and polyethylene wax); hydrogenated oils that are solid at 25°C (e.g., hydrogenated castor oil, hydrogenated jojoba oil, hydrogenated palm oil, hydrogenated tallow, and hydrogenated coconut oil); and fatty esters that are solid at 25°C (e.g., C20-40 alkyl stearate).

[0048] The aqueous phase of lotions for use in the present invention may also contain one or more organic liquids that are miscible with water at room temperature (25° C.). Exemplary water-miscible organic liquids include monohydric and polyhydric alcohols and derivatives thereof, such as C2-C6 alkanols (e.g., ethanol and isopropanol); C2-C10 glycols and polyols (e.g., glycerol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, caprylyl glycol, dipropylene glycol, and diethylene glycol); C3-C16 glycol ethers (e.g., mono-, di-, or tripropylene glycol (C1-C4) alkyl ethers and mono-, di-, or triethylene glycol (C1-C4) alkyl ethers), and polyethylene glycols having 2 to 12 oxyethylene units.

[0049] Lotions for use in the present invention may also contain surface-active ingredients, such as emulsifiers and solubilizers, to allow two or more immiscible ingredients to be combined uniformly and to aid in stabilizing the composition. Emulsifiers that may be used to form O / W or W / O emulsions include sorbitan oleate, sorbitan sesquioleate, sorbitan isostearate, sorbitan trioleate, PEG-20 sorbitan isostearate, polyglyceryl-3-diisostearate, polyglycerol esters of oleic acid / isostearic acid, polyglyceryl-6 hexalicinoleate, polyglyceryl-4-oleate, polyglyceryl-4 oleate / PEG-8 propylene glycol cocoate, polyglyceryl-2 dipolyhydroxystearate, PEG-30 dipolyhydroxystearate, and the like. Ingredients include oleamide DEA, TEA myristate, TEA stearate, magnesium stearate, sodium stearate, potassium laurate, potassium ricinoleate, sodium cocoate, sodium tallowate, potassium castor oil, sodium oleate, cetyl phosphate, diethanolamine cetyl phosphate, potassium cetyl phosphate, sodium glyceryl oleate phosphate, dimethicone copolyol, cetyl dimethicone copolyol, octyl dimethicone ethoxyglucoside copolyol, dimethicone copolyol crosspolymer, and lauryl methicone copolyol.

[0050] Combinations of any of the above materials or product forms may also be used.

[0051] Compositions for use in the present invention (described above) may contain additional active substances to improve the physical and / or aesthetic properties of the scalp and / or hair. Examples include amino acids, vitamins, minerals and / or antioxidants, emollients, moisturizers, sunscreens, anti-irritants, exfoliants, plant extracts (e.g., pomegranate extract, birch extract, green tea extract, chamomile extract and licorice extract), and mixtures thereof.

[0052] The composition for use in the present invention (described above) may contain additional functional ingredients to improve the physical and / or aesthetic properties of the composition itself.Examples include inorganic pigments (e.g., titanium dioxide, zirconium oxide, cerium oxide, zinc oxide, iron oxide, chromium oxide, manganese violet, ultramarine blue, chromium hydrate, and ferric blue); organic pigments (e.g., carbon black and organic lakes of barium, strontium, calcium, or aluminum); pearlescent agents (e.g., mica coated with titanium dioxide and / or iron oxide); dyes, preservatives (e.g., disodium EDTA, benzyl alcohol, methylparaben, phenoxyethanol, propylparaben, ethylparaben, butylparaben, and isobutylparaben); pH adjusters, and fragrances (e.g., essential oils, flower oils, resins, gums, balsams, natural extracts from beans, mosses, and other plants, and synthetic aromatic materials).

[0053] Mixtures of any of the above materials may also be used.

[0054] Preservatives may also be incorporated into the compositions used in the present invention to protect against the growth of potentially harmful microorganisms. Suitable conventional preservatives include alkyl esters of parahydroxybenzoic acid, hydantoin derivatives, propionate salts, and various quaternary ammonium compounds. Illustrative, but non-limiting, examples of preservatives that may be used in the present invention include, for example, phenoxyethanol, sodium salicylate, methylparaben, butylparaben, propylparaben, diazolidinyl urea, sodium dehydroacetate, benzyl alcohol, sodium benzoate, iodopropynyl butylcarbamate, caprylyl glycol, disodium EDTA, or mixtures thereof. In particularly preferred embodiments, the preservative is sodium benzoate, phenoxyethanol, sodium salicylate, or mixtures thereof. Preservatives are preferably used in amounts ranging from 0.01 to 2% by weight of the composition.

[0055] It is further preferred that the composition used in the present invention comprises a cosmetic ingredient. Preferably, the cosmetic ingredient is selected from the group consisting of silicones, antibacterial agents other than antidandruff agents, foam boosters, fragrances, encapsulants (e.g., encapsulated fragrances), dyes, colorants, pigments, preservatives, thickeners, proteins, phosphate esters, buffers, pH adjusters, pearlescent agents (e.g., mica, titanium dioxide, mica coated with titanium dioxide, ethylene glycol distearate (INCI glycol distearate) and / or opacifiers), viscosity adjusters, emollients, sunscreens, emulsifiers, sensation-inducing active substances (e.g., menthol and menthol derivatives), vitamins, mineral oil, essential oils, lipids, natural active substances, glycerin, natural hair nutrients such as plant extracts, fruit extracts, sugar derivatives and amino acids, microcrystalline cellulose and mixtures thereof.

[0056] Preferably, the compositions used in the present invention comprise, based on the weight of the total composition, 0.01 to 20% by weight of at least one cosmetic ingredient, more preferably 0.05 to 10% by weight, even more preferably 0.075 to 7.5% by weight, and most preferably 0.1 to 5% by weight of at least one cosmetic ingredient.

[0057] method The present invention provides the use of glycine or a composition comprising glycine in inhibiting the growth of Malassezia restricta when applied to the external surface of the human body, the composition comprising at least 0.04% glycine by weight of the composition. Such inhibition can be used to treat dandruff. The use is preferably non-therapeutic in nature, and more preferably cosmetic in nature.

[0058] The present invention provides the use of glycine or a composition comprising glycine in balancing the microbiome (balancing means selectively reducing the number of harmful microorganisms, which are Malassezia restricta, while leaving unaffected the reduction in the number of resident bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes) on the external surfaces of the human body, said composition comprising at least 0.04% glycine by weight of the composition. Such microbiome balancing can be used to treat dandruff. The use is preferably non-therapeutic in nature, more preferably cosmetic in nature.

[0059] The present invention provides a method for inhibiting Malassezia restricta by applying glycine or a composition containing glycine to an external surface of the human body, the composition comprising at least 0.04% glycine by weight of the composition. Such inhibition can be used to treat dandruff. The method is preferably non-therapeutic in nature, and more preferably cosmetic in nature.

[0060] The present invention provides a method for balancing the microbiome (balancing means selectively reducing the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of commensal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes) by applying glycine or a composition containing glycine to the external surface of the human body, the composition comprising at least 0.04% glycine by weight of the composition. Such microbiome balancing can be used to treat dandruff. The method is preferably non-therapeutic in nature, and more preferably cosmetic in nature.

[0061] The present invention provides a method of applying glycine or a composition comprising glycine to an external surface of the human body to protect the surface from harmful microorganisms, which are Malassezia restricta, while ensuring the growth of resident bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes, the composition comprising at least 0.04% glycine by weight of the composition. The method is preferably non-therapeutic in nature, and more preferably cosmetic in nature.

[0062] The present invention provides glycine or a glycine-containing composition for use in inhibiting the growth of Malassezia restricta, the composition comprising at least 0.04% glycine by weight of the composition. Such inhibition can be used to treat dandruff.

[0063] The present invention provides glycine or a composition comprising glycine for use in balancing the microbiome on the external surfaces of the human body (balancing means selectively reducing the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of resident bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), the composition comprising at least 0.04% glycine by weight of the composition. Such microbiome balancing can be used to treat dandruff.

[0064] The present invention provides a composition comprising glycine or glycine for use as a pharmaceutical. The present invention also provides a composition comprising glycine or glycine for use as a pharmaceutical for inhibiting the growth of Malassezia restricta when applied to the external surface of the human body, the composition comprising at least 0.04% glycine by weight of the composition. The present invention also provides a composition comprising glycine or glycine for balancing the microbiome on the external surface of the human body (balancing means selectively reducing the number of harmful microorganisms that are Malassezia restricta, while not affecting the reduction in the number of commensal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), the composition comprising at least 0.04% glycine by weight of the composition.

[0065] The composition is suitably applied to the hair or scalp and massaged into the scalp surface. Generally, the equivalent of about 1 to 15 mL of composition per application is applied evenly to the treatment area daily or at least once a week for a period of at least 7 days, preferably at least 28 days, and more preferably at least 30 days.

[0066] The present invention is further illustrated by the following non-limiting examples. [Example]

[0067] Example 1 Microbial preparation M. restricta (CBS7877) was regenerated on modified Reeming-Notman agar (mLNA) plates from a -80°C freezer by incubating at 32°C for 5 days. The organisms were further cultured in 20 mL of modified Reeming-Notman broth (mLNB) at 32°C for 48 hours with shaking. 1 mL of the original culture was then transferred to 9 mL of fresh mLNB and incubated at 32°C for 48 hours with shaking before use.

[0068] Malassezia furfur (CBS1878) was regenerated on Pityrosporum broth (PB) agar by incubation at 32°C for 2 days. The organism was further cultured in 20 mL of liquid growth medium, PB broth, with shaking at 32°C for 48 hours. 1 mL of the original culture was then transferred to 9 mL of fresh PB and incubated with shaking at 32°C for 48 hours before use.

[0069] S. epidermidis (ATCC_12228) was recovered by overnight incubation on tryptic soy agar (TSA) at 37°C. The organism was further cultured overnight at 37°C in 20 mL of liquid growth medium, tryptic soy broth (TSB), for further use.

[0070] C. acnes (ATCC_6919) was regenerated on TSA plates by 5 days of anaerobically incubated at 37°C, and the microorganisms were further cultured in 20 mL of liquid growth medium TSB at 37°C for 4 days anaerobically before use.

[0071] Experimental method: Agar dilution MIC assay Growth medium agar plates were prepared containing no glycine (control) and different levels (by weight) of glycine: 0.04, 0.05, 0.1, 0.15, and 0.2%. For the fungi M. restricta and M. furfur, mLNA was used. For the bacteria S. epidermidis and C. acnes, TSA was used.

[0072] The optical density (OD) of each microbial culture was adjusted to: OD = 2, 1, 0.5, and 0.25 for M. restricta; OD = 0.8, 0.4, 0.2, and 0.1 for M. furfur; and OD = 0.6 for S. epidermidis and C. acnes, with serial 10-fold dilutions of 0.6, 0.6x10^-1, 0.6x10^-2, 0.6x10^-3, 0.6x10^-4, 0.6x10^-5, and 0.6x10^-6. Four microliters of each microbial inoculum was transferred onto the corresponding plate, incubated, and microbial growth was monitored. Duplicate sets of experiments were performed. Finally, plates with growing colonies were visually inspected once daily for up to 7 days for Malassezia and C. acnes, and for up to 2 days for S. epidermidis. Microbial growth under different conditions was compared by colony density. "No inhibition" means no change in microbial colony density as observed with the naked eye, "inhibition" means that microbial growth was inhibited and microbial colony density was reduced by at least 75%, and "no growth" means that little to no visible growth of microbial colonies was observed with the naked eye.

[0073] result The microbial growth was recorded and is shown in Table 1 below. Table-1

[0074] [Table 1]

[0075] From the table above, it is clear that Samples 1-5 containing glycine at levels consistent with the present invention were able to selectively inhibit the growth of harmful microorganisms (M. restricta) without any inhibitory effect on the growth of beneficial microorganisms (S. epidermidis and C. acnes). Furthermore, the results in the table above demonstrate that the use of compositions containing glycine at levels consistent with the present invention has minimal impact on the populations of other Malassezia species, such as Malassezia furfur (M. furfur).

[0076] Example 2 The antimicrobial efficacy of various amino acids was investigated against Malassezia restricta (M. restricta). Growth of M. restricta was monitored by culturing M. restricta in mLNB liquid medium for 3 days with or without the addition of 0.5% of various amino acids. To prevent the various amino acids from affecting the pH of the growth medium, the pH of all solutions was adjusted to the same level, pH 5.5. The same protocol was used to monitor microbial growth.

[0077] result The microbial growth was recorded and is shown in Table 2 below. Table-2

[0078] [Table 2]

[0079] From the above table, it is clear that sample 6, which contained levels of glycine consistent with the present invention, was able to inhibit the growth of harmful microorganisms (M. restricta), while samples containing other amino acids were not.

[0080] Example 3 This example demonstrates that a leave-on lotion containing certain levels of glycine can inhibit the growth of Malassezia restricta (M. restricta). Compositions are prepared according to the formulations detailed in Table 3. All ingredients are expressed as the active ingredient level as a weight percent of the total formulation.

[0081] Table-3 [Table 3]

[0082] Experimental Method: Using the agar dilution MIC assay from Example 1 Prepare mLNA with the lotion sample. Mix 10 g of lotion with 90 g of 1.1X mLNA medium.

[0083] The optical density (OD) of M. restricta was adjusted to OD = 2, 1, 0.5, and 0.25. Four microliters of the M. restricta suspension was added to the agar and cultured at 32°C for 7 days. The growth of M. restricta was observed visually once a day for 7 days. Microbial growth was compared based on colony density. "No inhibition" means no change in the microbial colony density observed visually. "Inhibition" means that microbial growth was inhibited and the microbial colony density was reduced by at least 75%. "No growth" means that almost no visible growth of the microbial colonies was observed.

[0084] result The microbial growth was recorded and is shown in Table 4 below. Table-4

[0085] [Table 4]

[0086] From the above table, it is clear that compositions containing levels of glycine consistent with the present invention (Samples 7-9) were able to inhibit the growth of harmful microorganisms (M. restricta).

Claims

1. 1. Use of glycine or a composition comprising glycine in inhibiting the growth of Malassezia restricta when applied to the external surface of the human body, said composition comprising at least 0.04% glycine by weight of the composition.

2. 2. The use according to claim 1, wherein the composition comprises glycine in an amount of 0.04 to 10%, preferably 0.15 to 5%, more preferably 0.2 to 2% by weight of the composition.

3. 3. The use according to claim 1 or 2, wherein the surface is human skin, preferably the scalp.

4. The use according to any one of claims 1 to 3, wherein the use is for inhibiting dandruff and promoting scalp health.

5. The use according to any one of claims 1 to 4, wherein the use has no inhibitory effect on the growth of indigenous bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes.

6. Use according to any one of claims 1 to 5, wherein the composition is a hair or scalp composition, preferably a leave-on hair or scalp composition.

7. 1. Use of glycine or a composition comprising glycine in balancing the microbiome on the external surface of the human body (balancing means selectively reducing the number of harmful microorganisms which are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), wherein the composition comprises at least 0.04% glycine by weight of the composition.

8. 8. The use according to claim 7, wherein the surface is human skin, preferably the scalp.

9. 9. The use according to claim 7 or 8, wherein the use is for inhibiting dandruff and promoting scalp health.

10. 1. A method for inhibiting Malassezia restricta by applying glycine or a composition containing glycine to an external surface of the human body, wherein the composition comprises at least 0.04% glycine by weight of the composition.

11. 1. A method for balancing the microbiome (balancing means selectively reducing the number of harmful microorganisms that are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes) by applying glycine or a composition comprising glycine to an external surface of the human body, wherein the composition comprises at least 0.04% glycine by weight of the composition.

12. 1. A method of applying glycine or a composition comprising glycine to an external surface of the human body to protect the surface from harmful microorganisms that are Malassezia restricta while ensuring the growth of resident bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes, said composition comprising at least 0.04% glycine by weight of the composition.

13. The method according to any one of claims 10 to 12, wherein the surface is human skin, preferably the scalp.

14. 1. Glycine or a composition comprising glycine for use in balancing the microbiome on the external surface of the human body (balancing means selectively reducing the number of harmful microorganisms which are Malassezia restricta, while leaving unaffected the reduction in the number of normal bacteria selected from Staphylococcus epidermidis and Cutibacterium acnes), the composition comprising at least 0.04% glycine by weight of the composition.

15. 1. Glycine or a composition comprising glycine for use in inhibiting the growth of Malassezia restricta, said composition comprising at least 0.04% glycine by weight of the composition.

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