Use of unsaturated fatty acids alone or in combination with antimicrobial peptide in a topical personal care composition

Abstract

The present invention relates to use of an unsaturated fatty acid for inducing secretion of anti-microbial peptides when applied on an external surface of the human body, like, skin, scalp, oral cavity. The invention also relates to a personal care composition comprising the unsaturated fatty acid and an anti-microbial peptide and / or booster thereof. The composition protects an external surface of the human body e.g. skin, scalp, oral cavity, from harmful or potentially harmful microorganisms.

Description

[0001] USE OF UNSATURATED FATTY ACIDS ALONE OR IN COMBINATION WITH ANTIMICROBIAL PEPTIDE IN A TOPICAL PERSONAL CARE COMPOSITION

[0002] Field of the invention

[0003] The invention relates to a new use of unsaturated fatty acids for inducing generation of antimicrobial peptides (AMPs), thereby protecting an external surface of the human body. This has application in improving the immunity of external surfaces of the body e.g., skin including scalp and the oral cavity of the human body, against harmful microorganisms. The invention also relates to a personal care composition comprising the unsaturated fatty acids and AMPs or booster thereof for providing antimicrobial benefit and protecting external surfaces of the body e.g. skin, against harmful microorganism.

[0004] Background of the invention

[0005] People tend to take care of their external surfaces e.g. skin, scalp and oral cavity. Skin is the primary line of defence that protects the human body from invading pathogens, like viruses and bacteria. As the primary defence organ, the skin tissue always remains in constant contact with the environment and therefore it has to face and resolve threats and challenges from invading pathogens. The exposed skin surface is not only challenged by pathogenic foreign bacteria, but it also remains in contact and interacts with the resident commensal bacteria. In spite of all these challenges from such foreign microbes, healthy skin remains infection free and also the number of the resident microflora generally remains constant. This equilibrium in the interaction between the skin tissue and the microbes is maintained as the skin has inbuilt sophisticated defence strategy of which antimicrobial peptides (AMPs) form an important part.

[0006] AMPs form an integral part of the skin’s own defence system. AMPs are ubiquitous in nature; and they typically exhibit a broad spectrum of activity against invading bacteria, fungi, viruses and parasites. AMPs are generally short peptides and in humans about 90 different AMPs are reported to be present. AMPs in general have two major physical features and they are a) cationic charge and b) a significant proportion of hydrophobic residues. The cationic charge of the AMPs promotes selectivity for negatively charged microbial surfaces whereas the hydrophobicity facilitates interactions with the cell membrane of the microbial species.

[0007] The present inventors have been working to provide hygiene benefits to consumers through the route of enhancing the AMP levels in external surfaces e.g., skin. They wish to provide this through use of ingredients which are perceived by the consumers to be more skin friendly and thereby less harsh. Further, they also wish to provide a personal care composition that provides antimicrobial benefits by way of killing or inactivating invading infectious microorganisms.

[0008] Specifically, one of the most common and leading causative agents for skin infection is the Staphylococcus aureus, causing various skin and soft tissue infections. Colonization of S. aureus on the host skin surface is the initial stage of infection, on breaching into the deeper tissues, the microbe establishes infection by employing its complex strategies. In particular, S. aureus overcomes the host innate system by producing a range of toxins such as haemolysins, leukotoxins that impairs the cellular membrane and causes lysis.

[0009] To achieve the goal of protecting external surfaces of the human body from harmful microorganisms, various actives were tested and after extensive research, the present inventors found that unsaturated fatty acid induce secretion of AMPs from keratinocytes thereby increasing the levels of AMPs on the surface e.g., skin. Further the AMPs so generated interact synergistically with the externally applied unsaturated fatty acids to provide antimicrobial activity against infective organisms e.g. Staphylococcus aureus (S. aureus), Escherichia coli (E. coli). The antimicrobial benefit was also found to be achieved through a composition comprising a combination of unsaturated fatty acids and AMPs e.g., defensins, histatins, cathelicidin, dermcidin, S100 peptides, RNAse peptides and mixtures thereof.

[0010] Summary of the invention

[0011] Accordingly, in a first aspect, the present invention relates to use of an unsaturated fatty acid for inducing secretion of anti-microbial peptides from keratinocytes, when applied on an external surface of the human body.

[0012] In a second aspect, the present invention relates to a personal care composition comprising: a. an unsaturated fatty acid, b. an anti-microbial peptide and / or a booster thereof, wherein when the composition comprises an anti-microbial peptide, then the ratio of the antimicrobial peptide to the unsaturated fatty acid, is in the range 1 :1000 to 1 :10000 by weight.

[0013] In a third aspect, the present invention relates to a method of providing protection to an external surface of the human body by way of inducing anti-microbial peptides (AMPs) comprising steps of: a. applying the composition according to the second aspect on such surfaces; and b. optionally, rinsing the surface.

[0014] Detailed description of the invention

[0015] All other aspects of the present invention will more readily become apparent from the description and examples which follow. Any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of’ or “composed of.” In other words, the listed steps or options need not be exhaustive. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word “about”. Numerical ranges expressed in the format " x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and may be abbreviated as “wt%”. The use of any and all examples or exemplary language e.g. “such as” provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed. Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use may optionally be understood as modified by the word “about”.

[0016] The composition of the invention is meant to be used for personal care or for cosmetic use. Such personal care composition may be classified as leave-on or rinse-off, and includes any product applied to a human body for improving appearance, cleansing, odour control or general aesthetics.

[0017] An external surface of the human body as used herein include skin, scalp, hair and oral cavity. The use as per this invention could be by way of applying unsaturated fatty acids or the composition as per the invention in a leave-on or in a rinse off product, and includes any product applied to a human body primarily for hygiene benefits but may also improve appearance, cleansing, odour control or general aesthetics. The composition can be in the form of a liquid, lotion, cream, foam, scrub, gel, soap bar or toner, or applied with an implement or via a face mask, pad, wipe or patch. Non-limiting examples of such compositions include leave-on products like skin lotions and creams, antiperspirants, deodorants, depilatories, lipsticks, foundations, mascara, sunless tanners, sanitizers, gels, sprays or sunscreen lotions or through rinse off products like shampoos, conditioners, shower gels, toilet bars, face wash, hand wash or body wash products.

[0018] In a first aspect, the present invention relates to use of an unsaturated fatty acid for inducing secretion of anti-microbial peptides from keratinocytes, when applied on an external surface of the human body, thereby providing protection against harmful microorganism.

[0019] An unsaturated fatty acid is found to induce and / or improve secretion of anti-microbial peptides from keratinocytes that are present in the skin, when applied on an external surface of the body. The AMPs so secreted aid in improving the immunity of external surfaces of the body which include oral cavity, scalp and skin on any part of the body e.g., face, neck, chest, back, arms, underarms, hands, legs, buttocks. Preferably, the external surface of the body is skin.

[0020] Preferably, the unsaturated fatty acid is C14-C24 unsaturated fatty acid. In other words, preferably, the unsaturated fatty acids as per the present invention are the unsaturated fatty acids having carbon chain length from 14 to 24, preferably from 16 to 22, preferably from 18 to 20. Preferably, the unsaturated fatty acids are selected from mono-, di- and tri-unsaturated fatty acids.

[0021] Examples of such unsaturated fatty acids include: monounsaturated fatty acids e.g. myristoleic acid, palmitoleic acid, sapineic acid, elaidic acid, vaccenic acid, oleic acid, gadoleic aicd, eicosenoic acid, erucic acid, nervonic acid, diunsaturated fatty acids e.g. linoleic acid, eicosadienoic acid, docosadienoic acid, tri unsaturated fatty acids e.g. linolenic acid, pinolenic acid, eleosteric acid

[0022] More preferably, myristoleic acid, palmitoleic acid, linoleic acid, linolenic acid and mixtures thereof, are used as the unsaturated fatty acids in the composition.

[0023] Preferably, the unsaturated fatty acids of the invention do not include conjugated fatty acids e.g. conjugated linoleic acid. Conjugated fatty acids are unsaturated fatty acids that contain unsaturated bonds at alternate carbon like for example, in conjugated linoleic acid which contains such unsaturated bonds at 9thand 11thcarbon atom.

[0024] The use of the unsaturated fatty acids claimed in first aspect of the present invention may be therapeutic or non- therapeutic. However, the most preferred use is for non-therapeutic e.g., for cosmetic application. Cosmetic use preferably means the use for prevention rather than cure. For example, bacteria like Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are commonly found on the human skin. These bacteria per se do not trigger a pathogenic effect in general, whilst commonly present on the skin. However, when they enter the human body through cuts on the skin and through acts like ingestion, these bacteria become pathogenic. Additionally, bacteria like S. hominis does not per se have any harmful effect on skin on its own. However, it reacts with skin biproducts like sebum to produce substance that cause foul smell, which is undesirable. For the purpose and definition of the invention S. hominis is also considered to be a harmful microorganism. Pseudomonas aeruginosa (P. aeruginosa), Cutibacterium acnes (C. acnes) are other examples of microorganism mostly found on the external surface of human.

[0025] Therefore, keeping the external surface of the body like e.g., hand and scalp, free of these microorganisms (bacteria) helps in preventing them from entering the human body or causing malodour, thereby achieving the desired hygiene. It may also be seen as improving or helping skin’s own defence mechanism. Thus, the use as claimed provides a protection in terms of reducing the harmful bacteria present in the skin by inducing secretion of AMPs.

[0026] The use as claimed may be for malodour reduction when applied on an external surface of the human body. Malodour generally caused by the reaction of skin biproduct e.g. sebum with some harmful microorganism like S. hominis. One of the advantages of present invention is that by way of inducing secretion AMPs, which there on helps in reducing S. hominis, thereby reducing malodour.

[0027] Without wishing to be bound by theory, it is believed that the unsaturated fatty acids activate keratinocytes, which are the major cells in the skin epidermis to provide the benefits of the present invention viz. inducing secretion of anti-microbial peptides (AMPs). This causes unsaturated fatty acids to boost protection shield against harmful microorganisms, i.e. improve the immunity of the external surface. Unsaturated fatty acids therefore provide protection for the body against infections by boosting the body’s own defence. In other words, the active primes the body surface for germ protection. The advantage of this is that it provides long-lasting protection e.g. up to 24 hours of protection against germs.

[0028] In a second aspect, the present invention relates a personal care composition comprising: a. an unsaturated fatty acid; and b. an anti-microbial peptide and / or a booster thereof, wherein when the composition comprises an anti-microbial peptide, then the ratio of the antimicrobial peptide to the unsaturated fatty acid, is in the range 1 :1000 to 1 :10000 by weight. It will be understood that the composition of this second aspect comprises an unsaturated fatty acid in combination with either an antimicrobial peptide or a booster thereof or a combination of them both. When the composition comprises AMPs, then the ratio of the AMP to the unsaturated fatty acids is in the range 1 : 1000 to 1 : 10000 by weight.

[0029] Preferably, the unsaturated fatty acids are the ones having carbon chain length from 14 to 24. Preferably, the unsaturated fatty acids are selected from mono-, di- and tri-unsaturated fatty acids. Examples of such unsaturated fatty acids include: monounsaturated fatty acids e.g. myristoleic acid, palmitoleic acid, sapineic acid, elaidic acid, vaccenic acid, oleic acid, gadoleic aicd, eicosenoic acid, erucic acid, nervonic acid, diunsaturated fatty acids e.g. linoleic acid, eicosadienoic acid, docosadienoic acid, tri unsaturated fatty acids e.g. linolenic acid, pinolenic acid, eleosteric acid

[0030] More preferably, myristoleic acid, palmitoleic acid, linoleic acid, linolenic acid and mixtures thereof, are used as the unsaturated fatty acids in the composition.

[0031] Preferably, the composition comprises from 0.000001 to 10 wt%, preferably from 0.00001 to 9 wt%, preferably from 0.0001 to 8 wt%, preferably from 0.001 to 7 wt%, preferably from 0.01 to 6 wt%, preferably from 0.1 to 5 wt%, preferably from 1 to 4 wt%, preferably from 2 to 3 wt% of one or more unsaturated fatty acids described above.

[0032] As described above, the composition comprises either AMPs or a booster thereof or both.

[0033] Preferably, the composition comprises AMPs. Preferably, AMPs are selected from defensins e.g. human beta defensin 1 , human beta defensin 2, human beta defensin 3 and human beta defensin 4; histatins e.g. histatin 5, histatin 7; cathelicidin e.g. LL-37; dermcidin e.g. dermcidin 1 ; S100 peptides e.g. psoriasin; and RNAse peptides e.g. RNAse7, which may be used in the present invention individually or as a combination. More preferably, AMPs are selected from human beta defensin 1 , human beta defensin 2, human beta defensin 3 and human beta defensin 4, LL-37 and mixtures thereof. Even more preferably, the AMP selected is human beta defensin 3, LL-37 and mixtures thereof.

[0034] Preferably, the composition comprises AMPs in an amount ranging from 0.000001 to 2 wt%, more preferably from 0.00005 to 1 wt% even more preferably from 0.00001 to 0.1 wt%, furthermore preferably from 0.0001 to 0.05 wt% and still more preferably from 0.001 to 0.01 wt%. When the composition comprises AMPs, then the ratio of the AMPs to an unsaturated fatty acid is preferably in the range from 1 :1000 to 1 :10000 by weight. Preferably, the ratio is 1 :1000 to 1 :7500, preferably 1 :1000 to 1 :5000, preferably 1 :3000 to 1 :5000, preferably 1 :3500 to 1 :4500 by weight. Preferably, the composition does not comprise LL-37 and oleic acid in ratio 1 :2000 by weight.

[0035] For example, when the composition comprises an AMP e.g., LL-37, then the weight ratio of LL- 37 to an unsaturated fatty acid e.g. oleic acid is 1 :10000 by weight.

[0036] Preferably, the composition comprises a booster of AMPs selected from niacinamide, 10- hydroxystearic acid, 12-hydroxystearic acid and mixtures thereof. By ‘AMP booster’ or ‘booster of AMPs’, it is preferably meant that boosters which induce and / or improves secretion of AMPs when applied on an external surface of the body, e.g. 12-hydroxystearic acid, induces the secretion of AMPs from the skin, preferably from keratinocytes.

[0037] Thus, the composition of the second aspect relates to covers a personal care composition comprising: a. an unsaturated fatty acid; and b. an AMP, wherein the ratio of the AMP to the unsaturated fatty acid, is in the range 1 :1000 to 1 :10000.

[0038] The composition of the second aspect also covers a personal care composition comprising: a. an unsaturated fatty acid; and b. a booster of AMPs preferably selected from those described above.

[0039] The composition of the second aspect also covers a personal care composition comprising: a. an unsaturated fatty acid, b. an AMP, wherein the ratio of the AMP to the unsaturated fatty acid is in the range from 1 :1000 to 1 :10000; and c. a booster of AMPs preferably selected from those described above.

[0040] Preferably, the composition is a leave-on product. Examples of leave-on products include a cream, a lotion, a gel, a sanitizer and a deodorant. ‘Leave-on’ composition preferably means a composition which is not required to be removed from the surface it is applied on to, e.g. skin, after the application of the composition; and such compositions may only get removed when a consumer / user takes a shower or a bath typically after several hours or after about a day.

[0041] If the composition is in the form of a cream, then it preferably further comprises from 3 to 25 wt%, more preferably 4 to 22 wt%, even more preferably from 7 to 20 wt%, furthermore preferably from 10 to 19 wt% and still more preferably 12 to 18 wt% saturated fatty acids. Such fatty acids when present in the composition along with a soap, provide the so-called vanishing cream effect, i.e. a composition, when applied on to the human skin, vanishes on the skin leaving behind no significant streaks of the composition.

[0042] The saturated fatty acids may be selected from saturated fatty acids having carbon atoms preferably in the range 10 to 22, more preferably 12 to 22, even more preferably 14 to 22, furthermore preferably 16 to 22, yet more preferably from 18 to 22. Examples of such saturated fatty acids that may be used in the composition include lauric, myristic, palmitic, stearic, isostearic, oleic, arachidic, behenic, erucic acid and mixtures thereof. Alternatively, the saturated fatty acid that may preferably be used is stearic acid or palmitic acid or a mixture thereof. The saturated fatty acid in the present invention is preferably hysteric acid which is substantially (generally about 90 to 95%) a mixture of stearic acid and palmitic acid where amount of palmitic acid may range from 40 to 65% and that of stearic acid may range from 34 to 58%.

[0043] If the composition is in the form of a cream, then it preferably further comprises from 0.1 to 10 wt%, more preferably 1 to 8 wt%, even more preferably 2 to 7 wt%, furthermore preferably 2 to 6 wt%, even furthermore preferably 2 to 5 wt% and most preferably 2 to 4 wt% soap.

[0044] Soap when present in the combination with the saturated fatty acids in the composition, it provides the so-called vanishing effect. Soap of the invention is generally prepared by in-situ neutralization of the saturated fatty acids that may be present in the composition. Thus, it is preferred that the soap has a carbon chain length that corresponds to the chain length of the additional fatty acids in the composition. The soap is formed from the saturated fatty acids through the use of alkali metal hydroxides e.g. sodium hydroxide or potassium hydroxide. Of the two, potassium hydroxide is more preferred. Thus, the soap is preferably a potassium soap (potassium salt of a saturated fatty acid).

[0045] Preferably, the leave-on composition of the invention comprises water. Amounts of water may preferably range from 10 to 95 wt%, more preferably from 15 to 85 wt%, even more preferably from 35 to 80 wt%, and furthermore preferably from 40 to 75 wt%. The leave-on composition of the invention may be in the form of an emulsion e.g. a water-in-oil emulsion or an oil-in-water emulsion, preferably an oil-in-water emulsion. In such cases, the composition may include mineral oils, silicone oils, and synthetic oils. Amounts of these materials may range from 0.1 to 50 wt%, and preferably, from 0.1 to 30 wt%, and most preferably, from 1 to 20 wt%, including all ranges subsumed therein.

[0046] Silicone oils may be divided into the volatile and non-volatile varieties. The term “volatile” as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, and preferably, from 4 to 5 silicon atoms. Linear volatile silicone materials generally have viscosities of less than 5 centistokes at 25°C while cyclic materials typically have viscosities of less than 10 centistokes (measured with a Brookfield Viscometer, RV No. 3 spindle at 20 PRM, standardized to mineral oil and at 25°C).

[0047] Nonvolatile silicone oils useful as carrier material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethylsiloxanes (like dimethicone, including crosspolymers and elastomers) with viscosities of from 5 to 100,000 centistokes at 25°C.

[0048] An often-preferred silicone source is a cyclopentasiloxane and dimethiconol solution.

[0049] The leave-on composition of the invention may further comprise emollients. Examples of emollients that may be used in the composition include stearyl alcohol, glyceryl monoricinoleate, mink oil, cetyl alcohol, isopropyl isostearate, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecan-2-ol, isocetyl alcohol, eicosanyl alcohol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethylpolysiloxane, din-butyl sebacate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, cocoa butter, corn oil, cotton seed oil, olive oil, palm kernel oil, rape seed oil, safflower seed oil, evening primrose oil, soybean oil, sunflower seed oil, avocado oil, sesame seed oil, coconut oil, arachis oil, castor oil, acetylated lanolin alcohols, petroleum jelly, mineral oil, butyl myristate, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate and mixtures thereof. Such emollients may preferably be present in amounts 0.1 to 30 wt%, more preferably from 1 to 25 wt%, even more preferably from 3 to 20 wt%, furthermore preferably from 5 to 15 wt% and still more preferably from 7 to 12 wt%. Emulsifiers (or surfactants) may be present in leave-on compositions comprising the components of the present invention. Total concentration of the emulsifier, when used, may range from 0.1 to 30 wt%, and preferably, from 2 to 20 wt%, and most preferably, from 1 to 9 wt% by weight of the composition. The emulsifier may be selected from the group consisting of anionic, non-ionic, cationic and amphoteric components. Particularly preferred non-ionic components are those with a C10 to C20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C2-C10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di-fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, nono- and di- C8-C20 fatty acids; and polyoxyethylene sorbitan as well as combinations thereof. Alkylpolyglycosides and saccharide fatty amides (e.g., methyl gluconamides) are also suitable non-ionic emulsifiers.

[0050] Preferred anionic emulsifiers include alkyl ether sulphate and sulfonates, alkyl sulphates and sulphonates, alkylbenzene sulphonates, alkyl and dialkyl sulphosuccinates, C8-C20 acyl isethionates, C8-C20 alkyl ether phosphates, alkylethercarboxylates and combinations thereof.

[0051] Cationic emulsifiers that may be used include, for example, palmitamidopropyltrimonium chloride, distearyldimonium chloride and mixtures thereof. Useful amphoteric emulsifiers include cocoamidopropyl betaine, C12-C20 trialkyl betaines, sodium lauroamphoacetate, and sodium laurodiamphoacetate or a mixture thereof.

[0052] Other generally preferred emulsifiers include glyceryl stearate, glycol stearate, stearamide AMP, PEG-100 stearate, cetyl alcohol.

[0053] A leave-on composition of the present invention may be in the form of a sanitizer composition that is intended for providing antimicrobial effect against harmful or potentially harmful microorganisms that may be present on the skin. Sanitizers preferably comprise 40 to 98 wt%, preferably 45 to 95 wt%, preferably 50 to 90 wt%, preferably 55 to 85 wt%, preferably 60 to 80 wt%, preferably 65 to 75 wt% e.g. 70 wt%, of C2 to C4 monohydric alcohols wherein said monohydric alcohols are selected from ethanol, isopropyl alcohol or mixtures thereof. Sanitizer may include certain polyols. Polyols in the composition according to the invention are preferably sorbitol, glycerol, polyethylene glycol, propylene glycol and combinations thereof. Sanitizers may preferably comprise from 0.01 to 1 wt. % of a thickening agent. More preferably the composition comprises 0.05 to 0.8 wt. % of a thickening agent, most preferably 0.08 to 0.2 wt% of a thickening agent. Water is generally present in a sanitizer composition from 5 to 40 wt%, preferably 10 to 40 wt%, preferably 12 to 35 wt%, preferably 25 to 30 wt%. Sanitizer may preferably comprise one or more fragrance compounds. Alternatively, the composition may be in the form of a wash-off composition. Examples of such wash-off composition include a hand-wash composition, a body-wash composition and a shampoo composition.

[0054] By ‘wash-off’, it is preferably meant that the composition applied on to a surface e.g. skin, is removed from the surface preferably with water. In other words, the surface is rinsed off with water and the composition so applied is removed. Typically, if the composition is formulated in the form of a wash-off composition, then the composition so applied is removed preferably within 5 minutes, more preferably within 3 minutes, even more preferably within 1 minute and furthermore preferably within 30 seconds e.g., 10 or 15 seconds of it being applied on a surface.

[0055] If the composition is formulated in the form of a wash-off composition, e.g. a shampoo or wash composition, then the composition preferably comprises a surfactant. In such case, the composition preferably comprises surfactants in an amount from 3 to 80 wt%, preferably 5 to 80 wt% surfactant. Based on the whether the wash-off composition is formulated in a liquid format or a solid format, amounts and types of surfactants may vary.

[0056] For example, if the wash-off composition is formulated as a solid wash-off composition e.g. a bar, then the composition may comprise preferably from 25 to 70 wt%, preferably from 30 to 65 wt%, preferably from 35 to 60 wt%, preferably from 40 to 55 wt% surfactant e.g. a fatty acid soap and / or from 0.1 to 25 wt% preferably 1 to 22 wt%, preferably 3 to 20 wt%, preferably 5 to 15 wt% nonsoap synthetic surfactant whereby the bars typically comprise 10 to 25 wt%, preferably 12 to 22 wt%, preferably 14 to 20 wt%, preferably 14 to 16 wt% water.

[0057] Alternatively, for example, if the wash-off composition is formulated as a liquid wash-off composition e.g. hand-wash or body-wash composition, then the composition preferably comprises from 3 to 20 wt%, preferably from 5 to 20 wt%, more preferably from 5 to 18 wt%, even more preferably from 5 to 15 wt%, further more preferably from 5 to 14 wt% and still more preferably from 5 to 12 wt% surfactant.

[0058] Preferably, surfactants present in such wash-off compositions may be selected from an anionic surfactant, a cationic surfactant, a non-ionic surfactant, an amphoteric surfactant, a zwitterionic surfactant and mixtures thereof.

[0059] A suitable anionic surfactant may be selected from a soap and / or a non-soap synthetic anionic surfactant. Examples of soap include soaps that may be used as anionic surfactants in a wash-off composition include those formed after saponification of saturated fatty acids having carbon atoms in the range from C8 to C20 with an aqueous alkali e.g. sodium hydroxide, potassium hydroxide and ammonium hydroxide. Typical examples of soap include caprylate (C8), caprates (C10), laurate (C12), myristate (C14), palmitate (C16, stearate (C18) and oleate (C18:1) formed with an aqueous alkali mentioned earlier. Thus, preferred soaps are selected from potassium caprylate, potassium caprate, potassium laurate, potassium myristate, potassium palmitate, potassium stearate, potassium oleate, sodium caprylate, sodium caprate, sodium laurate, sodium myristate, sodium palmitate sodium stearate, sodium oleate and mixtures thereof. Often, soaps may be present as a mixture of soaps formed from fatty acids of varying chain lengths.

[0060] Preferably, a non-soap synthetic anionic surfactants is selected from alkyl sulphates, alkyl ether sulphates (AES), alpha olefin sulphonates (AOS), isethionates, taurates and mixtures thereof.

[0061] Examples of alkyl sulphates that may be used as non-soap anionic surfactant in the composition include sodium lauryl sulphate (SLS), sodium myristyl sulphate, ammonium lauryl sulphate (ALS); sodium pareth sulphate, and mixtures thereof.

[0062] Examples of AES that may be used as non-soap anionic surfactants include anionic surfactants of the general formula:

[0063] R1-(OR’)n-O-SO3‘ M+, wherein:

[0064] R1 is saturated or unsaturated C8-C16, preferably C12-C14 alkyl chain; preferably, R1 is a saturated C8-C16, more preferably a saturated C12-C14 alkyl chain;

[0065] R’ is ethylene; n is from 1 to 18; preferably from 1 to 15, more preferably from 1 to 10 and even more preferably from 1 to 5,

[0066] M+ is a suitable cation which provides charge neutrality, preferably sodium, calcium, potassium, or magnesium, ammonium, more preferably a sodium cation or ammonium.

[0067] Examples of AES that may be used as non-soap anionic surfactants in the composition include sodium lauryl ether sulphate (SLES), sodium myristyl ether sulphate and sodium palmityl ether sulphate, ammonium lauryl ether sulphate (ALES) and mixtures thereof. Preferred AES is SLES having 1 to 3 ethylene oxide units per molecule. SLES having 1 to 2 ethylene oxide units per molecule is more preferred. Examples of AOS that may be used as non-soap anionic surfactant in the composition include sodium olefin sulphonate. Examples of isethionate that may be used as non-soap anionic surfactant in the composition include, sodium lauryl isethionate; sodium cocoyl isethionate. Examples of taurates that may be used as non-soap anionic surfactant in the composition include sodium taurates such as sodium lauryl methyl taurate and sodium cocoyl methyl taurate.

[0068] Preferably, nonionic surfactants are selected from: fatty alcohol ethoxylates with saturated carbon chain and having HLB higher than

[0069] 15.5 e.g. Brij® 35 (also known as Brij® L23), fatty alcohol ethoxylates with unsaturated carbon chain with HLB higher than 12, e.g. Brij® 97 and Brij® 99, polyoxyethylene sorbitan alkyl esters with saturated C12 to C16 carbon chain and having HLB higher than 12; e.g. Tween® 20, polyoxyethylene sorbitan alkyl esters with unsaturated C18 carbon chain and having HLB higher than 9; e.g. Tween® 80, Tween® 81 ; and Tween® 85; alkyl glucosides e.g. decyl glucoside, and mixtures thereof.

[0070] Preferably, amphoteric surfactants are selected from betaines e.g. cocamidopropyl betaine (CAPB), sulfobetaine, cocoamphoacetate and mixtures thereof. More preferably, amophoteric surfactants are selected from betaine, sulfobetaine and mixtures thereof. Furthermore preferably, amphoteric surfactants selected is CAPB. Amphoteric surfactants provide foam boost and improve sensorial properties of the composition.

[0071] If the composition is formulated as a liquid wash-off composition, then it preferably comprises water in an amount from 50 to 95 wt%, more preferably from 60 to 90 wt%, even more preferably from 70 to 85 wt%, furthermore preferably from 75 to 80 wt% and still more preferably from 80 to 85 wt% water.

[0072] The composition of the first aspect described above preferably further comprises preservatives to protect against the growth of potentially harmful microorganisms. Examples of ingredients that may be used as preservatives in the composition include alkyl esters of para hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. More preferably, ingredients that may be used as preservative in the composition are sodium benzoate, iodopropynyl butyl carbamate, methylisothiazolinone, iodopropynylbutylcarbamate, phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea, sodium dehydroacetate, ethylhexylglycerin, benzyl alcohol, alkane diols and mixtures thereof. The alkane diols that are suitable for use as preservative are C6-C12 alkanes that are vicinally substituted with hydroxy groups. Illustrative examples include 1 ,2-octane diol (caprylyl glycol), 2,3-octane diol, 1 ,2-nonane diol, 1 ,2-decane diol, 1 ,2-hexane diol, 3,4-octane diol, mixtures thereof or the like where caprylyl glycol is typically the most preferred. When present in the composition, preservatives are added preferably in an amount 0.001 to 5 wt%, more preferably 0.01 to 3 wt% and most preferably 0.02 to 2 wt%.

[0073] Preferably, the composition further comprises one or more skin brightening agents. Such one or more skin brightening agents may be selected from vitamin B6, vitamin C and its derivatives, vitamin E, glutathione precursors, resorcinol, phenyl ethyl resorcinol, 4-alkyl resorcinol e.g. 4- ethyl resorcinol, 4-butyl resorcinol, 4-hexyl resorcinol, and mixtures thereof.

[0074] Alternatively, the one or more skin brightening agents may also be selected from galardin, adapalene, ammonium lactate, arbutin, butyl hydroxy anisole, butyl hydroxy toluene, citrate esters, deoxy arbutin, 1 ,3-diphenyl propane derivatives, 2,5-dihydroxybenzoic acid and its derivatives, 2-(4-acetoxyphenyl)-1 ,3-dithiane, 2-(4-hydroxyphenyl)-1 ,3-dithiane, ellagic acid, glucopyranosyl-1 -ascorbate, gluconic acid, glycolic acid, , 4-Hydroxy-5-methyl-3[2H]-furanone, 4- hydroxyanisole and its derivatives, 4-hydroxybenzoic acid derivatives, hydroxy caprylic acid, inositol ascorbate, linoleic acid, magnesium ascorbyl phosphate, 5-octanoyl salicylic acid, salicylic acid, 3,4,5-trihydroxybenzyl derivatives, acetylglucosamine, pitera extract, symwhite, calcium pantothenate (Melano-block), seppiwhite and mixtures thereof.

[0075] Such one or more skin brightening agents may preferably be present in an amount from 0.1 to 10 wt%, more preferably from 1 to 7 wt% and even more preferably from 3 to 5 wt%.

[0076] Preferably, the composition further comprises a polymer. The polymer acts as thickener in the composition and improves sensorial properties of the composition. The polymer is preferably selected from the following classes:

[0077] • acrylate I R-methacrylate copolymer e.g. acrylates / steareth-20 methacrylate copolymer (commercially available as Aculyn™ 22) and acrylates / beheneth-25 methacrylate copolymer (commercially available as Aculyn™ 28),

[0078] • acrylate I R-methacrylate crosspolymer e.g. acrylates / steareth-20 methacrylate crosspolymer (commercially available as Aculyn™ 88),

[0079] • acrylates copolymer (commercially available as Aculyn™ 33),

[0080] • acrylate / R-alkyl acrylate crosspolymer e.g. acrylates / C10-C30 alkyl acrylate crosspolymer (commercially available as Pemulen™ TR-2), • copolymer of ammonium acryloyldimethyltaurate with vinyl pyrrolidone (commercially available as Aristoflex® AVC),

[0081] • copolymer of sodium acryloyldimethyltaurate with vinyl pyrrolidone (commercially available as Aristoflex® A VS); and

[0082] • crosspolymer of acryloyldimethyltaurate with R-alkyl acrylate and methyacrylate e.g. Ammonium acryloyldimethyltaurate / beheneth-25 methacrylate crosspolymer (commercially available as Aristoflex® HMB and Aristoflex® BLV); and mixtures thereof.

[0083] Alternatively, the composition may comprise cellulose-based thickeners such as hydroxyethyl cellulose, hydroxypropyl methyl cellulose and mixtures thereof. More preferably, the polymer is selected from acrylate I R-methacrylate copolymer, acrylates copolymer and mixtures thereof. Preferably, the composition comprises 0.1 to 5 wt%, more preferably 0.5 to 4.5 wt%, even more preferably 1 to 4 wt%, furthermore preferably from 1 .5 to 3.5 wt%, still more preferably from 2 to 3 wt% of these polymers.

[0084] The composition may further comprise a range of other optional ingredients that include antioxidants, binders, buffering agents, colorants, astringents, fragrance, opacifying agents, conditioners, exfoliating agents, skin soothing agents, and skin healing agents.

[0085] In addition to the product formats and application to the surface e.g. skin, the composition of the second aspect may also be formulated to be suitable for application to other external surfaces of the body e.g. to oral cavity, through oral care compositions; or e.g. to scalp and hair, through hair care compositions; or to axilla, through deodorant compositions, described as follows:

[0086] Oral Care

[0087] When the personal care composition is formulated for oral care, it preferably includes a cosmetically acceptable base which may be an abrasive, a thickener, a humectant or an orally acceptable surfactant. The product may be delivered in the form of an ointment, a gel, a dentifrice or a mouthwash. Oral care compositions preferably comprise an abrasive. Gels usually contain silica, whereas opaque creams generally contain calcium-based abrasives, especially chalk. Preferred toothpaste compositions have 5 to 60 wt% calcium-based abrasive.

[0088] In a preferred aspect, the composition comprises a thickener. Typically, thickening silica, sodium carboxymethyl cellulose and / or a carbomer is / are preferred thickeners for use in the composition of the invention. Thickener, when present, preferably makes up from 0.01 to about 10 wt%, more preferably from 0.1 to 9 wt%, and most preferably, from 1.5 to 8 wt% of the composition. Suitable humectants are preferably used in the oral care composition of the present invention. Glycerin, polyethylene glycol, sorbitol or mixtures thereof are the preferred humectants. The humectant may be present in the range of from 10 to 90% by weight of oral care compositions.

[0089] Preferably, an oral care composition comprises a surfactant. Preferably the composition comprises at least 0.01 wt% surfactant, more preferably at least 0.1 wt% and most preferably from 0.5 to 7 wt%. The preferred anionic surfactants are sodium lauryl sulphate and / or sodium dodecylbenzene sulfonate. Most preferably the surfactant is sodium lauryl sulphate.

[0090] Water may preferably be included in 5 to 95 wt%, in particular, 10 to 75 wt%, and especially at from 10 to 60 wt%, furthermore preferably 10 to 45 wt% by total weight of the composition.

[0091] The oral care composition of the present invention may contain a variety of other ingredients which are common in the art to enhance physical properties and performance. These ingredients include antimicrobial, anti-caries agents, plaque buffers, fluoride sources, vitamins, plant extracts, desensitizing agents, anti-calculus agents, biomolecules, flavours, proteinaceous materials, preservatives, opacifying agents, colouring agents, pH-adjusting agents, sweetening agents, particulate abrasive materials, polymeric compounds, buffers and salts to buffer the pH and ionic strength of the compositions, and mixtures thereof. Such ingredients typically and collectively make-up less than 20 wt% and preferably from 0.0 to 15 wt%, and most preferably, from 0.01 to 12 wt%, including all ranges subsumed therein.

[0092] Hair Care

[0093] As per a preferred aspect of the invention, the composition may be used for hair care or cleansing. One medium through which this may be delivered is that of a shampoo. The composition of the invention especially shampoos are formulated with an anionic surfactant e.g. an alkyl sulphate and / or ethoxylated alkyl sulphate surfactant. These anionic surfactants are preferably present at a level of from 1 to 20%. Preferred alkyl sulphates are C8-18 alky sulphates, more preferably C12-18 alkyl sulphates, preferably in the form of a salt with a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. An example is sodium lauryl ether sulphate (SLES). Preferred ethoxylated alkyl sulphate anionic surfactant is sodium lauryl ether sulphate (SLES). SLES having an average degree of ethoxylation of from 0.5 to 3, preferably 1 to 3 is especially preferred. Shampoos preferably additionally comprise an amphoteric surfactant preferably a betaine surfactant preferably an alkyl amidopropyl betaine surfactant for example cocamidopropyl betaine. In a preferred embodiment, the composition comprises from 0.1 to 10 wt%, preferably from 0.5 to 8 wt%, more preferably from 1 to 5 wt% of a betaine surfactant.

[0094] To enhance deposition of actives from compositions of the invention especially shampoos, cationic polymers are generally included therein. In the present invention too, it is preferred that the composition additionally includes 0.01 to 2.0 wt% of a cationic polymer. The cationic polymer is preferably guar hydroxypropyl trimonium chloride.

[0095] When conditioning benefits are to be delivered through the composition of the invention the composition is called a hair conditioner. Typically, the most popular conditioning agents used in hair care compositions are water-insoluble oily materials such as mineral oils, naturally occurring oils such as triglycerides and silicone polymers. Conditioning benefit is achieved by the oily material being deposited onto the hair resulting in the formation of a film, which makes the hair easier to comb when wet and more manageable when dry. An especially useful conditioning agent is a silicone compound, preferably a non-volatile silicone compound. The pH of the composition is preferably equal to or higher than 4.0, more preferably in the range of 5.0 to 7.0.

[0096] The hair conditioning composition usually comprises conditioning surfactants selected from cationic surfactants, used singly or in admixture. Particularly useful cationic surfactant for use in conditioners according to the invention is cetyltrimethylammonium chloride, behenyltrimethylammonium chloride or stearamidopropyl dimethylamine. Hair conditioning compositions of the invention preferably may also additionally comprise a fatty alcohol.

[0097] Deodorant products

[0098] A specific class of personal care composition compositions is deodorant compositions. These compositions are usually applied to areas of the skin which generate body odour like the underarm region. These products work by either masking the odour or by ensuring that odour causing molecules are not generated or by killing or inactivating the odour causing microorganisms. A class of such products are also known as anti-perspirant products as they reduce or minimize the amount of sweat that is generated by the person.

[0099] These products can be applied cosmetically and topically to the skin, broadly speaking, by one of two methods. In one method, sometimes called a contact method, a composition is wiped across the surface of the skin, depositing a fraction of the composition as it passes. In the second method, sometimes called the non-contact method, the composition is sprayed from a dispenser held proximate to the skin. The spray can be developed by mechanical means of generating pressure on the contents of the dispenser, such as a pump or a squeezable sidewall or by internally generated pressure arising from a fraction of a liquefied propellant volatilizing, the dispenser commonly being called an aerosol.

[0100] There are broadly speaking two classes of contact compositions, one of which is liquid and usually applied using a roll-on dispenser or possibly absorbed into or onto a wipe, and in the second of which the desired active is distributed within a carrier liquid that forms a continuous phase that has been gelled. In one variation, the carrier fluid comprises a solvent for the desired active and in a second variation, the active remains as a particulate solid that is suspended in an oil, usually a blend of oils.

[0101] Stick or soft solid compositions:

[0102] Many different materials have been proposed as gellant for a continuous oil phase, including waxes, small molecule gelling agents and polymers. They each have their advantages and of them, one of the most popular classes of gellant has comprised waxes, partly at least due to their ready availability and ease of processing, including in particular linear fatty alcohol wax gellants. A gelled deodorant composition is applied topically to skin by wiping it across and in contact with the skin, thereby depositing on the skin a thin film.

[0103] Roll-on:

[0104] Liquid compositions that are applicable from a roll-on broadly speaking can be divided into two classes, namely those in which an active is suspended in a hydrophobic carrier, such as a volatile silicone and those in which the active is dissolved in a carrier liquid. The latter has proven to be more popular. There are mainly two sorts of dissolving carrier liquid, namely carriers that are predominantly alcoholic, which is to say the greater part of the dissolving carrier fluid comprises ethanol and the second class in which the carrier liquid is mainly water. The former was very popular because ethanol is a mild bactericide in its own right, but its popularity waned because it stings, especially if the surface onto which the composition has been applied has been damaged or cut, such as can easily arise during shaving or other de-hairing operations.

[0105] The second class of formulations that is an alternative to alcoholic formulations comprise a dispersion of water-insoluble or very poorly water-soluble ingredients in an aqueous solution of the active. Herein, such compositions will be called emulsions. Roll-on emulsions commonly comprise one or more emulsifiers to maintain a distribution of the water-soluble ingredients.

[0106] Aerosol compositions:

[0107] Deodorant compositions may be delivered through an aerosol which comprises a propellant in addition to the other ingredients described hereinabove. Propellants herein generally accord with one of three classes; i) low boiling point gases liquefied by compression, ii) volatile ethers and iii) compressed non-oxidising gases.

[0108] Class i) is conveniently a low boiling point material, typically boiling below -5°C, and often below -15°C, and in particular, alkanes and / or halogenated hydrocarbons. This class of propellant is usually liquefied at the pressure in the aerosol canister and evaporates to generate the pressure to expel the composition out of the canister. Examples of suitable alkanes include particularly propane, butane or isobutene. The second class of propellant comprises a very volatile ether of which the most widely employed ether hitherto is dimethyl ether. This propellant can advantageously be employed at relatively low weight ratio of propellant to base formulation, for example to as low as 5:95. It can also be employed in admixture with, for example, compressible / liquefiable alkane gasses. The third class of propellant comprises compressed nonoxidising gasses, and in particular carbon dioxide or nitrogen. Inert gases like neon are a theoretical alternative.

[0109] The compositions described herein, namely leave-on or wash off are preferably for topical application on the external surface of human. Preferably the application is non-therapeutic in nature.

[0110] In another aspect, the composition of the second aspect may be used for protecting an external surface of the body from harmful microorganisms. Preferably, the use is non-therapeutic or cosmetic in nature. An external surface of the body may be skin, hair including scalp, oral cavity.

[0111] In another aspect, the present invention relates to a method of providing protection an external surface of the human body by way of inducing secretion of anti-microbial peptides (AMPs) comprising steps of: a. applying the composition according to of the second aspect on such surfaces; and b. optionally, rinsing the surface.

[0112] The step of application, the step a., may be carried out simply by taking a suitable amount, e.g. 5 mL or 2 grams (depending on whether the composition is in liquid or solid form), of the composition on hands and gently spreading it over an external surface e.g. skin. The composition, if required, may also be applied using an applicator in which case, a user is expected to use the applicator to carry out the step of applying the composition; and spread the composition using the applicator on the surface. As an option, the method comprises step b., where the composition so applied in step a., is optionally rinsed off from the skin it was applied on to. If carried out, the step b., may preferably be carried out within 5 minutes, more preferably within 4 minutes, even more preferably within 3 minutes, furthermore preferably within 2 minutes and yet more preferably within 1 minute e.g. 30 seconds, or 15 seconds, from carrying out step a. Such optional step b. is particularly required to be carried out within 5 minutes, if the composition is formulated into a wash-off type of composition e.g. a face wash composition. Preferably, the method is non-therapeutic / cosmetic in nature. Th method may be adopted by consumer as their part of daily hygiene habit, like bathing with soap, or applying moisturizing lotions.

[0113] Preferably, such harmful microorganisms are one or more of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Cutibacterium acnes (C. acnes).

[0114] The invention is now further described by way of the following non-limiting examples.

[0115] Examples

[0116] Culture preparation

[0117] E. coli / S. aureus was inoculated from glycerol stock to TSA slants. Slants were incubated at 37°C aerobically for 24 hours until saturated growth is seen. These slants were then used to streak TSA agar plates which are then incubated at 37°C for about 16 hrs. One loopful of this plate culture was dissolved (pipetting and vortexing) in 10 mM sodium phosphate buffer pH 5.8 (~10ml of buffer). Optical density (OD) was checked, and culture was adjusted to 0.6 OD for E. coli and 0.2 for S. aureus at 620 nm. This OD value at 620nm corresponds to ~108CFU / mL (Colony Forming Unit / millilitre). The culture was serially diluted to get 106CFU / mL.

[0118] Preparation of actives

[0119] Unsaturated fatty acids

[0120] Oleic acid, linoleic acid and myristoleic acid are all dissolved in DMSO and used in concentrations shown in tables below.

[0121] A MPs

[0122] Working stocks of 10 pg / mL of LL37 (an AMP) was prepared by diluting it in water. This working stock was used for adding to the reaction wells as shown in tables below where 0.1 pg / mL LL37 is equal to 0.00001 wt%. Effect of an unsaturated fatty acid on gene expression levels of an AMP using 3D Living Skin Equivalent (from Mattek) was studied as follows:

[0123] 12-well plates indicating the treatment / exposure conditions were labelled and 1 mL of medium was added in to each well. Tissue from the agarose-containing package was removed carefully using sterile forceps and transferred into the labelled 12 well plates containing media and the plates were incubated at 37°C, 5% CO2 incubator for 12 to 18 hrs. After the overnight incubation, under sterile conditions the lid was removed from the 12-well plate and 1 mL / well of fresh, prewarmed medium was added in to each well of the plates. The tissues were then carefully blotted and placed on a sterile plate for dosing. Oleic acid was prepared as 1 % solution in water and sonicated using a bath sonicator for 10 mins. Each tissue was dosed with 10 pL of 1 % Oleic Acid and the inserts were then placed in the well. A vehicle control (sonicated water) was also included in experiment. One set of 3 tissues are retained as a no treatment control. Each test compound was carried out in three replicates. The plate was then incubated at 37°C, 5% CO2 incubator for 24 hrs. On day 2, the plates were removed from the incubator and all the tissues were rinsed with sterile Dulbecco’s phosphate buffered saline. After that, all tissues were cut using a sterile scalpel and then immersed in 500 pL of RNeasy lysis buffer with p-Mercaptoethanol (100:1) in a labelled 1 .5 mL Eppendorf tube. These tissues were probed by qPCR for amplification of AMP genes and the fold change over the vehicle control was calculated.

[0124] Measurement of Antimicrobial efficacy

[0125] The test reaction was prepared in a 96 well microtiter plate with duplicate wells for each reaction. From the working stock of LL37 15 pL and 22.5 pL were added to the respective wells for 0.5 pg / mL and 0.75 pg / mL test concentrations. Fatty acid working stocks of 100 times higher the tested concentrations were prepared in DMSO and 3 pL of this was added in the respective wells. The total volume of the reaction in each well was made to 300 pl with water. The Contact time provided was 4 hours at 37°C. Post-incubation, the reactions were plated on pre-prepared TSA agar plates in requisite dilutions. Dilutions were made in D / E neutralizer, in a micro-titre plate. (270 pl of D / E + 30 pl reaction mixture, etc.). 100 pl volume of desired dilutions is spread plated onto prepared plates. Plates were incubated aerobically overnight. Colonies were counted at the end of the incubation to quantitate the log kill / survival. A difference of 0.5 and above of the combination tested for synergy over the sum of the individual activity / kill is considered a synergy.

[0126] Table 1 : Effect of an unsaturated fatty acid herein oleic acid, on AMP gene expression levels using 3D Living Skin Equivalent (from Mattek) as described above.

[0127] Table 2: Antimicrobial effect obtained against Staphylococcus aureus (ATCC 6538) when an unsaturated fatty acid herein oleic acid, was used in combination with an AMP herein LL-37.

[0128] Table 3: Antimicrobial effect obtained against Staphylococcus aureus (ATCC 6538) when an unsaturated fatty acid herein linoleic acid, was used in combination with an AMP herein LL-37.

[0129] Table 4: Antimicrobial effect obtained against Escherichia coli (ATCC 10536) when unsaturated fatty acids were used in combination with AMPs.

Claims

Claims1 . Use of an unsaturated fatty acid for inducing secretion of anti-microbial peptides (AMPs) from keratinocytes, when applied on an external surface of the human body.

2. Use as claimed in claim 1 for improving the immunity of the external surface of the human body.

3. Use as claimed in claims 1 or 2 wherein the external surface of the human body includes skin, scalp and oral cavity.

4. Use as claimed in any one of claims 1 to 3 wherein the unsaturated fatty acid is C14-C24 unsaturated fatty acid.

5. Use as claimed in any one of claims 1 to 4 wherein the use is non-therapeutic use.

6. A personal care composition comprising: a. an unsaturated fatty acid, b. an anti-microbial peptide and / or a booster thereof, wherein when the composition comprises an anti-microbial peptide, then the ratio of the anti-microbial peptide to the unsaturated fatty acid, is in the range 1 :1000 to 1 :10000.

7. The composition as claimed in claim 6 wherein the unsaturated fatty acid is C14-C24 unsaturated fatty acid.

8. The composition as claimed in any one of claims 6 or 7 wherein the anti-microbial peptide is selected from defensins, histatins, cathelicidin, dermcidin, S100 peptides, RNAse peptides and mixtures thereof.

9. The composition as claimed in any one of claims 6 to 8 wherein the booster of an antimicrobial peptide is selected from niacinamide, 10-hydroxystearic acid, 12-hydroxystearic acid and mixtures thereof.

10. The composition as claimed in any one of claims 6 to 9 wherein the composition is in the form of a leave-on composition.11 . The composition as claimed in any one of claims 6 to 9 wherein the composition is in the form of a wash-off composition further comprising from 3 to 80 wt% surfactant.

12. The composition as claimed in any one of claims 6 to 11 for use in protecting the external surface of the human body from harmful microorganisms.

13. A method for providing protection to an external surface of human body by way of inducing secretion of anti-microbial peptides (AMPs) from keratinocytes comprising steps of: a. applying the composition as claimed in any one of claims 6 to 12 on such surfaces; and b. optionally, rinsing the surface.

14. The method as claimed in claim 13 wherein the method comprises the step of rinsing the surface (step b) and is carried out within 5 minutes from applying the composition on to the surface.

15. The method as claimed in claim 14 wherein the surface is skin.

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