WO2022258404A1

WO2022258404A1 - Topical composition for restoring microbial diversity of scalp

Info

Publication number: WO2022258404A1
Application number: PCT/EP2022/064510
Authority: WO
Inventors: Ranjit Kaur Bhogal; Chung-Ching Chu; David Andrew Gunn; Fei-Ling LIM; Barry Murphy; Jennifer Elizabeth Pople; Mingming PU
Original assignee: Unilever Ip Holdings B.V.; Unilever Global Ip Limited; Conopco, Inc., D/B/A Unilever
Priority date: 2021-06-09
Filing date: 2022-05-30
Publication date: 2022-12-15

Abstract

The present invention relates to use of a piroctone compound in a topical composition for restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.

Description

TOPICAL COMPOSITION FOR RESTORING MICROBIAL DIVERSITY OF SCALP

Field of the Invention

The present invention relates to a method of restoring microbial diversity of scalp, which is dandruff scalp.

Background of the Invention

The skin is the largest organ of human body. It protects our body from external factors such as the environment, pollution and microbes. Our skin harbours a diverse range of microorganisms which live as a community and function as a component of skin biology. Due to the advent of next-generation sequencing technologies, we now know that the microbiome or microbiota of human skin is highly dependent on biophysical characteristics and chemical constitution of the skin. For example, sebaceous sites are dominated by Cutibacterium sp., whereas moist areas harbour Staphylococcus and Corynebacterium species. Any adverse alteration in the microbiome of our skin (dysbiosis) could lead to conditions, that may need at least cosmetic treatment as such seen in the case of acne, dry skin and dandruff.

Dandruff, a skin disorder common among many people globally. The condition is manifested by the shedding of clumps of dead skin cells from the scalp. It is known that microbiome dysbiosis, increased sebum production and inflammation are the most common contributing factors. The major fungal/bacterial species present on the scalp, namely Malassezia restricta, Malassezia globosa, Cutibacterium acnes,

Staphylococcus epidermidis and Staphylococcus capitis. Staphylococcus is one of the most abundant genera across both healthy and dandruff scalps. However, at species level, Staphylococcus capitis is reported to be positively associated with dandruff conditions, while Staphylococcus epidermidis is positively associated with non-dandruff scalp conditions.

Recent studies reveal that dandruff is associated with an altered microbiota involving multiple taxa, as evidenced by an increase in the abundance of certain microbes and a concomitant decrease in the abundance of some others. Such an imbalance often manifests itself as a dysbiotic condition like acne or dandruff. Other such dysbiotic conditions include atopic dermatitis and dry skin. To some extent, such conditions can be managed by cosmetic treatment by the application of topical compositions that contain one or more active ingredients.

The microbiome of skin can be balanced e.g. by reducing the overall microbial load of skin or by selectively reducing some while selectively increasing the count of some others.

In some cases, balancing the microbiota of skin refers to selectively increasing the microbial count of good microbes and/or reducing the same count of bad microbes. Good microbes are said to provide benefit to their host through e.g., competing with bad microbes for available nutrients and through secretion of good metabolites.

A bacterial/fungal community is characterized by the number of species present therein and their absolute numbers. This is called bacterial/fungal diversity. In order to compare the bacteria/fungal diversity of microorganisms, a variety of tools have been developed. Shannon-Weaver (or simply Shannon) and Simpson’s diversity index are commonly used in such measurements based on Operational Taxonomic Units (OTUs). OTUs can be defined at different levels of resolution such as phylum, class, order, family, genus, and species). ACE (Abundance-based Coverage Estimator) and Chaol indices are used to estimate richness (estimated richness; measurement of OTUs expected in samples given all the bacterial species that were identified in the samples).

Biological diversity means the variability among living organisms from the ecological complexes of which organisms are part, and it is defined as species richness and relative species abundance in space and time.

A measure of the number of different kinds of organisms present in a community is defined as richness, therefore richness refers to the number of different species present in a certain niche. If more species are present in “A” than “B”, “A” is richer than “B”. When it comes to species richness, it does not consider the number of individuals of each species present. Diversity is not only based on richness, but also evenness. Evenness compares the uniformity of the population size of each of the species present. A measure of the relative abundance of the different species consisting of a community is evenness. In general, when species richness and evenness increase, diversity also increases.

XP055874533 discloses anti-dandruff composition comprising piroctone olamine as active agent against dandruff and for fighting microorganisms causing dandruff. However, it does not disclose the impact of piroctone olamine on the diversity of microbiota of scalp.

EP3695825 A1 (Unilever) discloses a hair care composition against dandruff comprising piroctone olamine. It discloses that piroctone olamine is able to decrease the level of Malassezia species. However, it does not disclose the impact of piroctone olamine on the diversity of microbiota of scalp.

WO2013093823 A2 (VYOME BIOSCIENCES PVT LTD) discloses oil compositions comprising at least 0.01wt% piroctone olamine exhibiting antifungal activity against Malassezia furfur useful as anti-dandruff agent. However, it does not disclose the impact of piroctone olamine on the diversity of microbiota of scalp.

US2016058775 A1 (PRASAD SUDHANAND ET AL) discloses hair care compositions comprising at least 0.01% of piroctone olamine exhibiting antifungal (Malassezia species) and antibacterial activity. However, it does not disclose the impact of piroctone olamine on the diversity of microbiota of scalp.

JPH10265408 A (LION CORP) discloses a lotion for atopic dermatitis comprising at least 0.01 % of a piroctone compound. However, it does not disclose the impact of piroctone olamine on the diversity of microbiota of scalp.

US10071103 B2(VYOME BIOSCIENCES PVT LTD) relates generally to novel molecules compositions and formulations for treatment of bacterial infections in general and more specifically to bacterial infections with antibiotic-tolerant pathogens. It does not disclose the use of piroctone compound for restoring diversity of microbiota of dandruff scalp. US2019000734 A1 (STURGIS DAVID ARTHUR ET AL) relates to antiperspirant and deodorant compositions and methods relating thereto. It does not disclose the use of piroctone compound for restoring diversity of microbiota of dandruff scalp. Summary of the Invention

In accordance with a first aspect disclosed is use of a piroctone compound in a topical composition for restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.

In accordance with a second aspect of the invention disclosed is a method of restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp comprising a step of applying thereto a piroctone compound in a topical composition.

In accordance with a third aspect disclosed is a topical composition comprising a piroctone compound for use in restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.

In accordance with a fourth aspect disclosed is use of a piroctone compound for restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.

Brief Description of the figures Figure 1 shows the Beta diversity of bacteria of dandruff-subjects as compared to non dandruff subjects before and after treatment.

Figure 2 shows the Beta diversity of fungi of dandruff-subjects as compared to non dandruff subjects before and after treatment. Detailed Description of the Invention

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 is 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.

By ‘a cosmetic composition’ as used herein, is meant to include a composition for topical application to skin, hair and/or scalp of mammals, especially human beings. Such a composition is generally applied on to the desired topical surface of the body for a period of time from a few seconds to up to 24 hours. When the period of time of application is low say of the order of a few seconds to a few minutes after which the composition is rinsed off with water or wiped away, such a composition is known as a cleansing composition or a wash-off composition. On the other hand, When the composition is applied for longer period of time say from several minutes to up to 24 hours and washed off usually during the process of normal personal cleaning, such a composition is known as a leave-on composition. The composition as per the present invention includes any product applied to a human body for also improving appearance, cleansing, odor control or general aesthetics.

By "hair care composition" as used herein, is meant to include a composition for topical application to hair or scalp of mammals, especially humans. By topical is meant that the composition is applied to the external surface of the body. In the present invention this is achieved by applying the composition on the hair or scalp. Such a composition may be generally classified as leave-on or rinse off, and includes any product applied for improving the appearance, cleansing, odor control or general aesthetics of scalp and hair. The hair care composition of the present invention could be in the form of a liquid, lotion, cream, foam, scrub, gel, shampoo, conditioner, shower gel or bar. The haircare composition of the present invention is preferably a leave-on composition. Alternatively, the hair care composition of the present invention is a wash-off composition. Compositions for achieving the desired benefits by way of ingestion into the human body are excluded from the scope of the present invention.

Restoring the microbiota diversity used herein preferably means restoring the alpha diversity of microbiota which means increasing or decreasing the number of different types of microbes and/or the evenness of the different types of microbes in the microbiota of a subject. In some embodiments, the microbiota diversity is increased. In some embodiments, the number of different genera of bacteria in the microbiota is increased. In some embodiments, the number of different species of bacteria in the microbiota is increased. In some embodiments, the number of different strains of bacteria in the microbiota is increased. In some embodiments, the microbiota diversity is decreased. In some embodiments, the number of different genera of bacteria in the microbiota is decreased. In some embodiments, the number of different species of bacteria in the microbiota is decreased. In some embodiments, the number of different strains of bacteria in the microbiota is decreased. In some embodiments, the number of genera, species and strains in the microbiota is restored.

Restoring the microbiota diversity used herein alternatively means restoring the beta diversity of microbiota which means the similarity of a community of microbes in the microbiota of a subject. Beta diversity is a measure of the difference in microbial composition between two samples or groups of samples based on taxonomic abundance, presence or absence, or on phylogenetic distances. Samples or groups of samples that are similar to each other have a low variation in beta diversity where samples or groups of samples that are different to each other have high variation in beta diversity.

“Amenable skin” means scalp which has dandruff. Wherein the term “normal healthy skin” preferably refers to skin which is free from any infection. Wherein the term” healthy scalp” preferably refers to scalp which is free from dandruff. Chad is Abundance-based estimator of species richness

where F1 and F2 are the count of singletons and doubletons, respectively, and S_obs is the number of observed species.

Chad is a nonparametric method for estimating the number of species in a community. The Chad richness estimator was developed by Anne Chao and is based on the concept that rare species infer the most information about the number of missing species. Because the Chad richness estimator gives more weight to the low abundance species, only the singletons and doubletons are used to estimate the number of missing species. Therefore, this index is particularly useful for data sets skewed toward the low-abundance species.

A microbe can be described as a tiny living organism, such as bacterium, fungus, or virus. A microbiome or microbiota refers collectively to all the microbes on or in the human body. In other words, a microbiome is a community of microbes. A balanced microbiota containing an appropriate diversity of organisms helps to maintain health and is essential for human development, immunity, health and wellbeing. Each of our individual microbiomes adapts throughout our lifetime and people can achieve a healthy microbiome in different ways. lAmenable skin means the scalp having dandruff.

Dandruff is a common scalp condition, characterized by excessive flaking and itch. It is generally accepted that the presence of dandruff is associated with changes in microbe ecology, altered lipid composition, inflammation and abnormal epidermal barrier function. The Malassezia yeast has long been considered as one of the main microbial drivers for dandruff. Severity of dandruff is generally associated with an increased abundance of Malassezia restricta. In addition, a trend towards an increase in the relative proportions of Staphylococcus to Cutibacterium is observed as dandruff scores increase, suggesting an imbalanced microbial ecology in the dandruff-affected scalp.

In accordance with the present invention, it is preferred that the microbes are bacteria or fungi, more preferably bacteria. Alternatively, the microbes are protozoans or viruses. Without wishing to be bound by theory it is believed that balanced microbiota of scalp having dandruff, is a result of a piroctone compound in the topical composition with the host defense mechanism.

Diversity In accordance with one aspect of the invention, restoring diversity of microbiota of scalp having dandruff includes restoring alpha diversity, determined using an alpha diversity index. The richness of microbes of scalp having dandruff is improved to the level normally indicative of healthy scalp. Preferably the alpha diversity measures include at least one of Shannon Index, Chad, Observed OTUs, ACE, Simpson or Fisher, more preferably Chad which indicates the richness of microbes of scalp.

It is preferred that the alpha diversity index as represented by Chad index of the scalp having dandruff after restoring is increased to a level normally indicated of healthy scalp.

Alternatively, the diversity is determined using a beta diversity index. It is preferred that the beta diversity of the scalp having dandruff is restored to a level normally indicative of healthy scalp. More preferably the beta diversity measures includes Bray-Curtis dissimilarity, Jaccard distance or and weighted/unweighted UniFrac.

The Composition

It is preferred that the topical composition comprises 0.001 to 5.0 wt% of a piroctone compound. When the composition comprises a piroctone compound, it preferably comprises 0.01 to 5%, more preferably 0.05 to 2%, still more preferably 0.5 to 1% of piroctone compound by weight of the total composition. It is preferred that the piroctone compound is piroctone olamine.

Piroctone Olamine is an olamine salt of the hydroxamic acid derivative piroctone. It is commonly known as piroctone ethanolamine with the trade name Octopirox^®. The piroctone olamine according to the present invention is a 1:1 compound of 1- hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone with 2-aminoethanol and is also designated 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H) pyridinone monoethanolamine salt. The CAS number is 68890-66-4 and the compound has the general formula (II) as below:

When the composition comprises piroctone olamine it preferably comprises 0.01 to 5%, more preferably 0.05 to 2%, still more preferably 0.5 to 1% of piroctone olamine by weight of the total composition.

It is preferred that the topical composition is a cosmetic composition. Alternatively, the topical composition is a medicament or a pharmaceutical composition.

The cosmetic composition is preferably in the form of a wash-off or a leave-on composition, more preferably a wash-off composition. Alternatively, it is a wash-off cosmetic composition, more preferably a hair care composition comprising 0.01 to 5.0 wt% of a piroctone compound.

Leave-on composition preferably means a composition which is not required to be removed or washed off from the human body after the application of the composition. When the composition is in the form of a leave-on composition, the composition is preferably a deodorant (stick, roll-on or spray), a hand sanitizer, a body lotion, a skin cream or body spray. Leave-on compositions are to be distinguished from compositions which are applied to the skin and subsequently removed, either by washing, rinsing, wiping, or the like either soon after or during the application of the product. Surfactants typically used for rinse-off compositions have physico-chemical properties giving them the ability to generate foam/lather in-use with ease of rinse; they can consist of mixtures of anionic, cationic, amphoteric, and nonionic surfactants. Wash-off composition preferably means a composition which is intended/required to be removed from the body by washing with solvent preferably water after the application of said composition like e.g. a shampoo, a hand wash composition and a face wash composition. In case of wash-off compositions, a cosmetically acceptable base preferably further comprises a surfactant.

For example, if the composition is in the form of a shampoo, in addition to water, the cosmetically acceptable base preferably comprises an anionic surfactant e.g. an alkyl sulphate and/or ethoxylated alkyl sulfate surfactant. These anionic surfactants are preferably present at a level of from 1 to 20 wt%, more preferably from 2 to 16 wt%, even more preferably from 3 to 16 wt%. Preferred alkyl sulfates are C8 to 18 alkyl sulfates, more preferably C12 to 18 alkyl sulfates, preferably in the form of a salt with a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium.

It is preferred that the topical composition comprises a cosmetically acceptable base. Examples of ingredients that may be used as cosmetically acceptable base includes water, fatty acids, soaps (salts of fatty acids), alcohols and mixtures thereof.

When the composition for use in the invention is a hair care composition, it preferably is a wash-off composition, especially shampoo or a conditioner. The preferred use of the cosmetic composition is in a shampoo. The cosmetic composition may suitably comprise from 50 to 90%, preferably from 60 to 80% water by weight of the total shampoo composition. Shampoo compositions for use in the invention will typically comprise one or anionic surfactants such as sodium laureth sulfate, sodium oleyl succinate, ammonium lauryl sulfosuccinate, ammonium lauryl sulphate, sodium dodecylbenzene sulphonate, triethanolamine dodecylbenzene sulfonate, sodium cocoyl isethionate, sodium lauryl isethionate, sodium N-lauryl sarcosinate, sodium lauryl sulfate, sodium lauryl ether sulfate (n) EO, (where n ranges from 1 to 3), ammonium lauryl sulfate and ammonium lauryl ether sulfate (n) EO, (where n ranges from 1 to 3) .

Mixtures of any of the above described materials may also be used. The total amount of anionic surfactant in shampoo compositions for use in the invention generally ranges from 5 to 30%, preferably from 8 to 20% by weight of the total weight of the composition.

Shampoo compositions for use in the invention may also include co-surfactants such as nonionic surfactants, which can be included in an amount ranging from 0.5 to 8%, preferably from 2 to 5% (by weight based on the total weight of the composition) and/or amphoteric or zwitterionic surfactants, which can be included in an amount ranging from 0.5 to 8%, preferably from 1 to 4% by weight based on the total weight of the composition. Representative nonionic surfactants include alkanolamides such as cocamide monoethanolamide and cocamide monoisopropanolamide; alkyl polyglucosides such as cocoglucoside and lauryl glucoside; and acyl glucamides such as cocoyl methyl glucamide. Representive amphoteric surfactant includes cocamidopropyl betaine. It is more preferred that the shampoo composition for use in the invention comprises sodium laureth sulfate and co-surfactant which is cocamidopropyl betaine.

Mixtures of any of the above described materials may also be used. Shampoo compositions for use in the invention may also include one or more cationic polymers, which can be included in an amount ranging from 0.01 to 5%, preferably from 0.05 to 2% by weight based on the total weight of the composition. Representative cationic polymers include cationic polysaccharide polymers such as cationic cellulose derivatives and cationic guar gum derivatives such as guar hydroxypropyltrimethylammonium chloride.

Shampoo compositions for use in the invention may also include one or more suspending agents, which can be included in an amount ranging from 0.05 to 5%, preferably from 0.1 to 3% (by weight based on the total weight of the composition). Representative suspending agents include polyacrylic acids, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid-containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, heteropolysaccharide gums and crystalline long chain acyl derivatives such as ethylene glycol distearate.

The shampoo composition further preferably comprises a suspending agent. Suitable suspending agents are polyacrylic acids, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid- containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, heteropolysaccharide gums and crystalline long chain acyl derivatives. The long chain acyl derivative is desirably selected from ethylene glycol stearate, alkanolamides of fatty acids having from 16 to 22 carbon atoms and mixtures thereof. Ethylene glycol distearate and polyethylene glycol distearate are preferred long chain acyl derivatives, since these impart pearlescence to the composition. Polyacrylic acid is available commercially as Carbopol® 420, Carbopol® 488 or Carbopol® 493. Polymers of acrylic acid cross-linked with a polyfunctional agent may also be used; they are available commercially as Carbopol® 910, Carbopol® 934, Carbopol® 941 and Carbopol® 980.

Suitable cross-linked polymers of acrylic acid and acrylate esters are Pemulen® TR1 and Pemulen® TR2. A suitable hetero polysaccharide gum is xanthan gum, for example that available as Kelzan. The present invention now will be demonstrated by way of following non-limiting examples.

Examples

Example 1

These examples are to explore the effect of a prototype shampoo with Octopirox^® on scalp microbiome through investigation of both scalp fungal and bacterial communities of dandruff scalp and healthy scalp.

The shampoo formulations are prepared as below in Table 1.

Table 1

A clinical study was conduction where a group of subjects who were classified as suffering with dandruff and a group of subjects who have healthy scalp were treated for 4 weeks with a shampoo containing Octopirox^®.

Following treatment assessment was made of changes / differences in microbiome profiles (bacteria and fungi) between the groups. Alpha Diversity:

Chaol - An alpha diversity metric used to examine the “richness” of a sample. How many types of bacteria / fungi are present in a sample. Beta Diversity: A measure used to examine the differences in complete community composition taking into account all the organisms in the sample.

• Bray Curtis: Examines differences based on the abundance of all microbes

• Jaccard: Examines differences based presence or absence of microbes

• Unweighted Unifrac: Phylogenetics differences without using abundances measures

The observations concerning alpha diversity (Chaol Index) of bacteria are presented in Table 2. Table 2

Diversity is an important characteristic of microbiome that may be unique to different body sites. Changes in diversity of microbiota is usually an indication of dysbiosis.

Alpha diversity and beta diversity are commonly used to describe the diversity of microbiome within samples (alpha) and among samples (beta) respectively. In the present experiments, the alpha diversity was assessed by the Chaol Index. The observations in Table 1 indicate that alpha diversity was lower in dandruff as compared to the healthy scalp microbiome (P<0.05). After 4-weeks of treatment of the dandruff subjects, the Chaol Index significantly increased and thereby restored to a level normally indicative of healthy scalp (there was no difference between the levels of Chaol diversity between treated dandruff subjects and healthy subjects p>0.5) Beta Diversity of bacteria was examined using Unweighted Unifrac metric.

As illustrated in Figure 1, a significant dissimilarity was observed between the healthy scalp and dandruff subjects (FDR<0.05) using the Unweighted Unifrac metric on bacterial data.

After 4-weeks of cosmetic treatment with the shampoo composition comprising piroctone olamine, the beta diversity of bacteria of dandruff subjects is moved closer to that of the healthy scalp subjects (Refer Figure 1). The shift in the microbial profiles suggests that the shampoo composition restored diversity of microbiota of skin (dandruff scalp) to a level normally indicative of healthy skin.

Beta Diversity of fungi was examined using Bray Curtis metric. As illustrated in Figure 2, a significant dissimilarity was observed between the healthy scalp and dandruff subjects (FDR<0.05) using the Bray Curtis metric on fungal data..

After 4-weeks of cosmetic treatment with the shampoo composition comprising piroctone olamine, the beta diversity of fungi of dandruff subjects is moved closer to that of the healthy scalp subjects (Refer Figure 2). The shift in the microbial profiles suggests that the shampoo composition restored diversity of microbiota of skin (dandruff scalp) to a level normally indicative of healthy skin.

In conclusion, a shampoo composition comprising piroctone olamine is found to restore the microbiome diversity in dandruff scalp via increasing the alpha diversity of the microbiome, which was lower prior to treatment compared to healthy scalp. Meanwhile, it is found to restore the microbiome diversity in dandruff scalp via restoring the beta diversity of microbiota of dandruff scalp to a level normally indicative of healthy skin.

Claims

1. Use of a piroctone compound in a topical composition for restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.

2. Use as claimed in claim 1 wherein said topical composition is a cosmetic composition.

3. Use as claimed in claim 1 or 2 wherein the alpha diversity index as represented by Chad index of the scalp having dandruff after restoring is increased to a level normally indicated of healthy scalp.

4. Use as claimed in any of claims 1 to 3 wherein said microbes are bacteria or fungi, preferably bacteria.

5. Use as claimed in any of claims 1 to 4 wherein the beta diversity of the scalp having dandruff is restored to a level normally indicative of healthy scalp.

6. Use as claimed in any of claims 1 to 5 wherein said composition comprises 0.01 to 5.0 wt% of said piroctone compound.

7. Use as claimed in any of the claims 1 to 6 wherein said piroctone compound is piroctone olamine.

8. A method of restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp comprising a step of applying thereto piroctone compound in a topical composition.

9. A topical composition comprising piroctone compound for use in restoring diversity of microbiota of scalp having dandruff to a level normally indicative of healthy scalp; further wherein the richness of microbes of scalp having dandruff after restoring is improved to a level normally indicated of healthy scalp.