Field of the invention

The present invention relates to use of a combination of a saccharide and glycerol for protection of skin against undesirable bacteria. The present invention is especially useful in formulating compositions which act as prebiotics by skin commensal bacteria like S. epidermidis to produce metabolites like lactic acid which by way of the present invention has been shown to inhibit growth of harmful bacteria like E. Coli, S. Aureus among others. The present invention is especially useful as it provides protection in the short term i.e. rapidly as well as in long-lasting fashion (i.e. in sustained manner). Further, with the use of the present invention there is no need to use conventional antimicrobial actives which may destroy the microbiome of the skin especially in those of babies.

Background of the invention

Skin in mammals are considered as one of the largest organs in the body, especially one which has the largest surface area. Skin forms the first line of defence against microorganisms which may invade the body though the air, water, food or material that come in contact with the body. When the body is infected on the skin or systemically, traditional approach to such hygiene problems has been to treat the skin/ body with antimicrobial actives that reduce or kill the germs. Recent research indicates that a lot of the bacteria that permanently reside on the skin (called skin commensal bacteria) do not actually cause infections, rather they are beneficial bacteria that protect the skin against disease causing pathogens. Several mechanisms have been proposed to explain the protection and some of the popular ones are: physically occupying space on skin to prevent colonization of pathogens; producing metabolites that ward of harmful possibly pathogenic organisms; generating metabolites that strengthen the innate defence mechanisms to prevent infection by harmful pathogens; and providing other benefits such as maintaining skin pH, barrier function etc. Thus, of late, there is a trend in moving away from the approach of treating the skin with broad spectrum antimicrobial actives to kill all microoganisms present on skin (or any other part of the body) as a means of treating infections. Rather, the approach is more towards targeted or selective inhibition/ killing of the desired microorganism to the exclusion of the skin commensal organism. This ensures that the skin microbiome is maintained in a healthy balanced state for long term hygiene and health.

The present inventors, in looking to solve the problem of selective kill of non-commensal bacteria on skin like E.coli and S. aureus directed their research to boosting the number and functionality of skin commensal bacteria through use of prebiotics or Selective Fermentation Inducers (SFI)

They found, during the course of the research, that S. epidermidis present on skin can ferment saccharides and glycerol in quite different manner. While saccharides enable production of metabolites which inhibit the growth of such pathogens in rapid fashion i.e in short time scales of about upto 24 hours, glycerol enables inhibition at long time scales (in a sustained manner) in the order of 24 to 96 hours. To the knowledge of the present inventors the use of a combination of a saccharide and glycerol is not known for inhibiting such type of bacteria in this dual manner.

It is known that saccharides increase the amount of skin commensal bacteria on skin e.g. WO2013/122931 (P&G) discloses topical use of a skin commensal prebiotic to improve the health of the skin microbiome, thereby potentially improving the condition and/or appearance of the skin.

WO2017/173244 (Gojo Ind) discloses a topical composition for reducing pathogen binding on a surface, said composition comprising an active ingredient; and at least one carrier, wherein said active ingredient comprises one or more of a prebiotic material, a probiotic material, and a synbiotic material wherein said topical composition reduces pathogen binding on a surface by a statistically significant amount.

It is thus an object of the present invention to provide for a composition for use in inhibiting growth of harmful microorganisms on the skin.

Summary of the invention

The first aspect of the present invention relates to a combination of a saccharide and glycerol for protecting skin from non-commensal bacteria via nourishing the skin commensal bacteria.

A preferred aspect of the present invention relates to use of the combination of the first aspect to provide both a rapid as well as long lasting protection. A second aspect of the present invention relates to use of the combination of the saccharide and glycerol in a composition suitable for application to the skin.

Another aspect of the present invention relates to a method of protecting skin against non-commensal bacteria comprising the step of applying a composition comprising a combination of a saccharide and glycerol on to skin.

Detailed description of the invention

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, 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. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description and claims 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 "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

The present invention relates to use of a combination of a saccharide and glycerol for protecting skin against non-commensal bacteria via nourishing skin commensal bacteria. Further, the present invention relates to use of this combination in a skin care composition as a skin protecting agent. Further, it relates to use of this combination in a skin care composition as commensal bacteria nourishing agent. Alternatively, the present invention also relates to use of this combination in a skin care composition as prebiotic for commensal bacterium. The present invention works by providing two complementary benefits which have not been known or reported before. The use of this combination provides fast or rapid protection against non-commensal bacteria. By fast or rapid protection is meant that the combination provides for benefit against such non commensal bacteria in the time range of 0 to 24 hours after application of the combination on to the skin. It also provides for long lasting i.e sustained long term protection. By long- lasting protection is meant that the combination provides for protection in the time range of 24 to 96 hours, after application on to the skin. This is unique since the present inventors have found that one benefit is achieved predominantly through use of a saccharide while the other benefit is achieved predominantly through use of glycerol. In the present invention the rapid protection is obtained mainly due to presence of a saccharide. The present inventors believe that this is achieved due to the saccharide being a prebiotic for a skin commensal bacterium which releases metabolites like lactic acid in the short term time range that act on the non-commensal bacterium in a rapid fashion. The long term benefit is believed to be due to presence of glycerol. Glycerol too is believed to act as a prebiotic for a skin commensal bacterium which releases certain metabolites like lactic acid over a longer period of time that act on the harmful bacterium in long-lasting fashion.

Any preference described hereinbelow with regard to one aspect of the invention (e.g. the composition or the use according to the invention) is also preferred for use in any one of the other aspects of the invention.

Preferred saccharide for use in the present invention is selected from monosaccharides including glucose, fructose, galactose, mannose or ribose; or disaccharides including sucrose, lactose, lactulose, maltose or trehalose; or oligosaccharides including fructose oligosaccharides or galactose oligosaccharides; or polysaccharides including alpha glucan or inulin. Most preferred saccharide for use in the present invention is sucrose.

It is also preferred that the use according to the invention is use of the combination of the saccharide and glycerol in a composition also comprising one or more of a surfactant, an emollient, a humectant or mixtures thereof. The invention thus also provides use of combination of a saccharide and glycerol in a skin care or skin cleansing composition as a skin microbiome balancing combination of agents. “Skin” as used herein is meant to include skin on any part of the body (e.g. face, neck, chest, back, arms, underarms, hands, legs, buttocks and scalp). It is especially useful for protecting the skin of babies. By babies is meant a child whose age is less than five years preferably less than three years more preferably less than a year. Such use against pathogens is preferably non-therapeutic, for example, delivered through a cosmetic or personal care composition. Further the composition of the invention and the method of the invention are also preferably for non-therapeutic use. It is to be understood that the benefits disclosed and claimed by combination of the saccharide and glycerol in the present invention could also be achieved by a composition comprising the combination of the saccharide and glycerol of the present invention and by the method of the present invention. Conversely the benefits disclosed and claimed in the composition and method of the present invention are to be understood to be due to the inclusion of combination of the saccharide and glycerol. Such a composition could be in the form of a leave-on composition. Alternatively and equally preferably it could be delivered through a wash-off format for delivering selective protective benefit to topical areas e.g. skin and/or hair of mammals, especially humans. Such a composition includes any product applied to a human body for also improving appearance, cleansing, or general aesthetics. The composition of the present invention may be delivered with a topically acceptable carrier which could be an anhydrous base, liquid, lotion, cream, foam, scrub, gel, or emulsion. The invention alternatively provides for a combination of a saccharide and glycerol for use in protecting skin from non-commensal bacteria via nourishing the skin commensal bacteria wherein the saccharide is selected from monosaccharides including glucose, fructose, galactose, mannose or ribose; or disaccharides including sucrose, lactose, lactulose, maltose or trehalose; or oligosaccharides including fructose oligosaccharides or galactose oligosaccharides; or polysaccharides including alpha glucan or inulin.

The composition as per the invention preferably comprises from 0.1 to 80%, more preferably 0.5 to 50%, further more preferably 0.5 to 20% of a saccharide by weight of the composition. The amount of glycerol in the composition of the invention is preferably in the range of 0.1 to 80%, more preferably 0.5 to 50%, further more preferably 0.5 to 20%by weight of the composition.

It is preferred that the weight ratio of the saccharide to glycerol, in the present invention is in the range of 1:1 to 1:4, preferably 1:1 to 1:3, more preferably 1:1 to 1:2.

The combination of a saccharide and glycerol as per this invention is preferably a prebiotic for a skin commensal bacterium. The skin commensal bacteria is preferably S. epidermidis. The skin is protected as per this invention from non-commensal bacteria which may be E.Coli, S. Aureus, P Aeruginosa, P aeries or mixtures thereof. Consumers often find such non-commensal bacteria to be unwanted or undesirable as they may provide certain negative attributes like producing itchiness, discomfort or malodour. In certain cases, they may even be harmful or in extreme cases be pathogenic. Therefore, the non-commensal bacteria are preferably unwanted bacteria, undesirable bacteria, harmful bacteria and/or pathogenic bacteria or bacteria with a combination of these attributes.

The composition of the invention is preferably a wash-off composition and this is enabled by including 1 to 80% by weight of a surfactant. In general, the surfactants may be chosen from the surfactants described in well known textbooks like "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, and/or the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in “Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Any type of surfactant, i.e. anionic, cationic, nonionic, zwitterionic or amphoteric can be used but preferred surfactant is of the anionic or non-ionic type.

The pH of a wash off composition as per the present invention is in the range of 5 to 11 , preferably in the range of 5.5 to 10.

The surfactant may be a soap. Soap is a suitable surfactant for personal washing applications of composition of the invention. The soap is preferably C8-C24 soap, more preferably C10-C20 soap and most preferably C12-C16 soap. The soap may or may not have one or more carbon-carbon double bond or triple bond. The cation of the soap may be alkali metal, alkaline earth metal or ammonium. Preferably, the cation of the soap is selected from sodium, potassium or ammonium. More preferably the cation of the soap is sodium or potassium.

The soap may be obtained by saponifying a fat and/or a fatty acid. The fats or oils generally used in soap manufacture may be such as tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process the fatty acids are derived from oils/fats selected from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed, soyabean, castor etc.

A typical fatty acid blend consisted of 5 to 30% coconut fatty acids and 70 to 95% fatty acids ex hardened rice bran oil. Fatty acids derived from other suitable oils/fats such as groundnut, soybean, tallow, palm, palm kernel, etc. may also be used in other desired proportions. The most preferred soap is a laurate soap. The soap, when present in solid forms of the present invention is present in an amount of 30 to 90%, preferably from 50 to 85%, more preferably 55 to 75% by weight of the composition. The soap, when present in liquid forms of the composition is present in 0.5 to 20%, preferably from 1 to 10% by weight of the composition.

Alternatively the surfactants are non-ionic surfactants, such as C8-C22, preferably Ce de fatty alcohol ethoxylates, comprising between 1 and 8 ethylene oxide the surfactants are preferably selected from primary alkyl sulphate, secondary alkyl sulphonates, alkyl benzene sulphonates, or ethoxylated alkyl sulphates. The composition may further comprise an anionic surfactant, such as alkyl ether sulphate preferably those having between 1 and 3 ethylene oxide groups, either from natural or synthetic source and/or sulphonic acid. Especially preferred are sodium lauryl ether sulphates. Alkyl polyglucoside may also be present in the composition, preferably those having a carbon chain length between C6 and C16. Suitable surfactant concentrations in liquid forms of cleaning application are generally more than 0.5 but less than 10%, preferably from 1 to 5 % by weight of the composition. In solid compositions, the surfactant is preferably present in 5 to 40%, preferably from 10 to 30% by weight of the composition.

Water may preferably be present in 10 to 90% by weight of the composition depending on the format of the composition. In solid composition water may be present in 10-30%, while in liquid or semi-solid composition, water may be present in 40 to 90%. When the composition in accordance with the invention is a leave on composition, it preferably comprises one or more surfactant, emollient, humectant, pigment and preservative.

The pH of a leave on composition as per the present invention is in the range of 5 to 9, preferably in the range of 5.5 to 8.

The carrier acts as diluent or dispersant for the ingredients of the compositions. The carrier may be aqueous-based, anhydrous or an emulsion, whereby a water-in-oil or oil- in-water emulsion is generally preferred. If the use of water is desired, water typically makes up the balance of the composition, which most preferably is from 40 to 80 % by weight of the composition.

In addition to water, organic solvents may optionally be included as carrier to assist any other carrier in the compositions of the present invention. Examples include alkanols like ethyl and isopropyl alcohol.

Other suitable organic solvents include ester oils like isopropyl myristate, cetyl myristate, 2-octyldodecyl myristate, avocado oil, almond oil, olive oil and neopentylglycol dicaprate. Typically, such ester oils assist in emulsifying the compositions, and an effective amount is often used to yield a stable, and most preferably, water-in-oil emulsion.

Emollients may also be used, if desired, as a carrier. Alcohols like 1 -hexadecanol (i.e. cetyl alcohol) are preferred. Other emollients include silicone oils and synthetic esters. Silicone oils suitable for use include cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5 silicon atoms. Non-volatile silicone oils useful as emollients include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The non-volatile polyalkyl siloxanes useful polydimethylsiloxanes. Silicone elastomers may also be used. The ester emollients that may optionally be used are: (i) alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate;

(ii) ether-esters such as fatty acid esters of ethoxylated fatty alcohols;

(iii) polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200- 6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl mono-stearate, 1,3- butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters; (iv) wax esters such as beeswax, spermaceti, stearyl stearate and arachidyl behenate; and,

(v) sterols esters, of which cholesterol fatty acid esters are examples.

Emollients, when present, typically make up from 0.1 to 50 % by weight of the composition, including all ranges subsumed therein.

Fatty acids having from 10 to 30 carbon atoms may also be included as carriers. Examples of such fatty acids include pelargonic, lauric, myristic, palmitic, stearic, isostearic, oleic, linoleic, arachidic, behenic or erucic acid and mixtures thereof. Moisturisation may be improved through use of petrolatum or paraffin. Thickeners may also be utilized as a portion of the carrier in the compositions. Typical thickeners include cross-linked acrylates (e.g. Carbopol ^® 982), hydrophobically-modified acrylates (e.g. Carbopol ^® 1382), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Amounts of the thickener may range from 0.001 to 5, optimally from 0.01 to 0.5 % by weight of the composition. Surfactants may also be present. When present, the total amount of surfactants is 2 to 40 % by weight, and preferably from 4 to 20 % by weight, optimally from 5 to 12 % by weight of the composition. The surfactant is selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C10-20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; mono- and di- fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di- C8-C20 fatty acids; block copolymers (ethylene oxide/propylene oxide); and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.

Preferred anionic surfactants include soap, alkyl ether sulfate and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, Csto 20 acyl isethionates, acyl glutamates, Cs to 20 alkyl ether phosphates and combinations thereof.

Various other ingredients may also be used in compositions. Actives are defined as skin benefit agents other than emollients and other than ingredients that merely improve the physical characteristics of the composition. Although not limited to this category, general examples include extender pigments such as talcs and silicas, as well as alpha- hydroxy acids, beta-hydroxy acids and zinc salts.

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

Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Particularly preferred preservatives are methyl paraben, propyl paraben, phenoxyethanol and benzyl alcohol. Preservatives are from 0.1 to 2 % by weight of the composition.

The packaging could be a patch, bottle, tube, roll-ball applicator, propellant driven aerosol device, squeeze container or lidded jar.

Without wishing to be bound by theory the present inventors believe that the combination of the saccharide and glycerol used in the present invention act as prebiotics for a skin commensal bacteria. The skin commensal bacteria preferably includes S. epidermidis.

The present invention is therefore intended to increase, promote, improve, maintain or sustain skin health and skin resiliency through improving the barrier health or NMF. This is attained through ensuring a healthy skin ecosystem through balanced microbiome health. By balanced microbiome health is meant that the ratio of commensal bacteria to non-commensal bacteria is maintained in a desired range for the skin health to be maintained, over both the short time as well as extended time frames.

This invention is especially useful for use on skin of babies where the use of broad spectrum anti bacterial agents are considered too harsh as it tends to interfere with the growth and maintenance of a healthy skin microbiome for long term health of the babies as they grow into adults. It is well accepted that baby skin barrier is more vulnerable than adult skin. Baby skin barrier is more delicate and water loss from the surface is faster than in adult skin. Similarly, the microbiome of baby skin is seen to be different from that of adult skin. Soon after birth, the baby’s skin as well as skin microbiome continues to change for up to about three to five years. T ogether with the barrier function, the microbiome plays a critical role in skin’s natural defence. It is thus imperative that the skin microbiome of babies and infants should be nourished to allow for its natural growth and maturation thereby maintaining optimum skin health. Thus, whether used on skin of babies or others, the composition for use in the present invention is substantially free of a conventional antimicrobial compound. By substantially free is meant that conventional antimicrobial actives are present in less than 0.1 wt%, more preferably less than 0.05 wt%, further more preferably less than 0.01wt%, even more further preferably less than 0.001 % by weight of the composition. By conventional antimicrobial actives is meant an antimicrobial active which kills or inhibits bacteria which attack skin like E. Coli,S. Aureus, P Aeruginosa, or P aeries among others. Preservatives which are included in compositions for their microbial stability are excluded from the definitions of antimicrobial actives mentioned above. Preservatives are included to ensure that the compositions are stable with respect to microorganisms which may grow and degrade the compositions. On the other hand, antibacterial compounds are included in compositions to hinder the growth of microorganisms which are present on the substrate (e.g skin) on which the compositions are applied.

Conventional antimicrobial compounds are generally those from the class of biguanides, bisphenols, halophenols, oligodynamic metal compounds like those of silver or zinc, cationic antimicrobial compounds or essential oil actives. Biguanide has a general base structure which may be further derivatised e.g. chlorhexidine or polyhexamethylene biguanide (PHMB). Bisphenols include triclosan or hexachlorophene. Halophenol include chloroxylenol (PCMX). Cationic compounds are another class of antimicrobial actives e.g. benzalkonium chloride, cetyl pyridinium chloride or cetyl trimethyl ammonium bromide.

The class of low boiling alcohols (which are fast acting antimicrobials) are especially not included in any substantial amount in the composition of the invention. Ideally they are absent from such compositions. By low boiling alcohols are meant monohydric alcohols with 2 to 5 carbon atoms.

When the composition of the invention is formulated for use on skin of babies, it is preferred that it is substantially free of a fragrance component. By a fragrance component is meant a molecule or a group of molecules that are compounded to form a perfume. The characteristic of such compounds is that they are volatile (to varying degrees) and offer a pleasant odour. In the context of perfumes or fragrance component, “by substantially free” is meant that that they are present in less than 0.05wt%, more preferably less than 0.01 wt%, further more preferably less than 0.005wt%, even more further preferably less than 0.001 % by weight of the composition.

With a goal of developing a range of products suitable for all types of skin especially for nourishing baby skin, this invention took upon an objective to examine various prebiotics for skin commensal bacterial and arrived at this unique combination of a saccharide and glycerol to attain the same. Surprisingly it was found that not only does it provide microbiome balancing benefit but does that over the short term as well as over long time frames.

Glycerol is a common ingredient found in a wide variety of skin cleansing and skin care products. The main function of glycerol is to act as a humectant, thereby keeping skin hydrated and healthy through improved barrier function. Using both in vitro and ex vivo methods, it has been found by way of the present invention that glycerol can be utilized by skin commensal bacteria as a food source, making glycerol a “skin prebiotic” ingredient. By utilizing glycerol and similar compounds, skin commensal bacteria can produce various fatty acids which are seen to be beneficial for skin. This is an additional benefit beyond the barrier benefits provided by glycerol. Through extensive experiments, the present inventors observed robust increase in various metabolites like fatty acids, organic acids, and diols on application of the combination of glycerol and saccharide on normal skin. Organic acids predominant of which was lactic acid was observed as the model metabolite. Lactic acid is seen to have multiple skin benefits such as hydration, resilience and barrier function. A product which is rich in glycerol and saccharide therefore is found to help nourish the skin’s especially baby skin’s, microbiome as well as improve barrier function towards a healthier skin for babies. The present invention thus provides for a composition for prevention of growth of non commensal bacteria on skin. Model non-commensal bacteria which have been tested and observed to be inhibited include E.Coli, S. Aureus, P aeruginosa, P. Acnes or mixtures thereof. An additional advantage of the invention therefore is that it provides for use of prebiotic glycerine that nourishes skin microbiome especially of babies, helps fight undesirable bacteria which in certain cases may be aggressors and protects the skin from infections and helps to deliver prebiotic moisture or prebiotic moisturization. In another sense, the invention is capable of caring for baby’s skin. One way that the invention does this is by providing a protective barrier on skin using the body’s natural microbiome and through use of prebiotics to feed the natural microbiome. This way, the present invention develops a healthy and resilient skin and improve and build a better barrier. Another advantage of the present invention is that it does not disrupt the skin pH, which plays an important role in microbiome health, and replenishes skin with essential nutrients to help skin retain its natural moisture.

Yet another aspect of the present invention relates to a composition comprising a saccharide and glycerol for use in protecting skin from non-commensal, even undesirable bacteria via nourishing the skin commensal bacteria. Though the use according to the invention generally is of a non-therapeutic nature, the composition may also be used in therapeutic applications. Thus, the composition preferably is a composition for use in therapeutically protecting skin from harmful bacteria via nourishing the skin commensal bacteria. The present invention also relates to a composition comprising a combination of a saccharide and glycerol for use in the treatment of skin conditions like eczema, atopic dermatitis, seborrheic dermatitis, acne, and dandruff.

Yet another aspect of the present invention relates to a method of protecting skin against harmful bacteria comprising the step of applying a composition comprising a combination of a saccharide and glycerol on to skin. The present inventors believe that this is enabled by this combination when included in the composition to behave as a prebiotic for skin commensal bacteria. They have observed this with experimental data on skin commensal bacteria S. epidermidis but it is likely possible with many other such beneficial bacteria known to colonise healthy skin. As a consequence of the metabolites secreted by such skin commensal bacterial, they believe that the skin is protected against harmful bacteria. The metabolites are generally of the fatty acids, organic acids, diols or phenol derivatives class. Additionally, the inventors believe that the method of the invention involves the composition comprising a saccharide and glycerol and the metabolites produced therefrom by the skin commensal bacteria, do not adversely affect the skin commensal bacteria but inhibit growth of non-commensal bacteria.

The invention thus provides for nourishing the good microbes thus maintaining the health of the microbiome. The invention helps in maintaining the host microenvironment to help the right microbes flourish. It does this by maintaining the pH mantle of the host. Alternatively, the present invention ensures that the microbiome balancing is obtained by selectively reducing the number of harm causing microbes residing on the external surface like skin whilst helping the beneficial microbes thrive. Thus, the method of the invention provides for a composition comprising a saccharide and glycerol and the metabolites produced therefrom by the skin commensal bacteria to deliver a beneficial effect on skin health.

The invention will now be demonstrated with the help of the following non-limiting examples. Examples

Examples A-C, 1-3: Production of Lactic acid using various amounts of sucrose and glycerine:

The following materials / combination of materials as in Table - 1 were used to study their effect on production of lactic acid. The method used to generate the data is given below. The amount of lactic acid (fermentation metabolite) generated is also summarized in Table -1.

Organic acid analysis:

Bacterial supernatant was transferred to petri plate and dried at 40 °C in hot air oven. After drying, the residue was dissolved in 1N HCI: Methanol mixture, followed by the addition of a methylating agent which was then heated at 75°C for 40 min.

The methylated organic acids were analyzed using GC-MS. Table -1

The data in the table above indicates that the combination as per the invention comprising both a saccharide (sucrose) and glycerol provides for both long term as well as short term enhancements in the production of lactic acid.

Inhibition of S. aureus: The following materials / combination of materials as in Table - 2 were used to study their effect on inhibition of S. aureus. The method used to generate the data is given below. The %growth inhibition is also summarized in Table -1.

Growth Inhibition assay S. epidermidis 12228 was inoculated in Tryptic Soy broth with and without prebiotic.

The broth cultures were incubated aerobically at 37 °C for 24h and 72h.

At end of each timepoint, the broth cultures were centrifuged, supernatants were collected.

S. aureus was grown in presence of these supernatants and kinetic growth curve was measured over a period of 24 to 72 hrs with 1 hr time interval at OD 620nm in iEMS Plate reader which was set to 37°C.

Table -2 The data in the table above indicates that the combination as per the invention comprising both a saccharide (sucrose) and glycerol provides for both long term and short term benefits in inhibition of S. aureus.