TECHNICAL FIELD
[001] The subject matter described herein in general relates to the antimicrobial
compositions, and in particular, relates to the field of cosmetic and personal care
products.
BACKGROUND OF INVENTION
[002] As the world population grows to alarming proportions, the associated risks of diseases and illness also keeps growing. Though mankind has made rapid strides in the field of health and medication. Personal care and hygiene remain areas of active research.
[003] Miliaria or prickly heat or heat rash is a characteristic skin ailment of eccrine sweat gland, which is highly predominant in hot and humid climatic conditions. It has great affinity towards neonates, as they have immature sweat glands. However, it can affect people of all ages and is characterized by excessive sweating with itchiness and discomfort. It is reported to be the result of sweat retention, which ultimately leads to the vesicular outbreak followed by maceration and obstruction of sweat ducts leading to symptoms that resemble acute acne. Improper diagnosis and treatment can lead to severe implications (Bukhari et al., Our Dermatol Online, DOI: 0.7241/ourd.20164.123). The primary pathogenicity is associated with the extracellular secretions from Staphylococcus epidermidis. S. epidermidis is a Gram positive opportunistic pathogen that is part of the normal human flora, typically the skin flora, and less commonly the mucosal flora. Present methods to combat prickly heat rash involve use of antiseptic powders that typically use zinc-based compounds. The drawback of such formulation is the associated toxicity. An effective method for combating both the toxicity as well as the possibility of drug-resistance is to utilize a combination of natural-occurring compounds.
[004] CN105663366 A attempts to address this problem by using a chinese medical formulation. CN104398838A uses a similar approach in combination with known antibacterial such as zinc oxide. The formulations however, comprise complex mixture of certain uncommon medicinal extracts and are hence not

convenient and economical to manufacture. Hence, there is need for antibacterial composition that utilizes naturally occurring compounds that are readily available.
SUMMARY OF THE INVENTION
[005] In an aspect of the present invention, there is provided an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2.
[006] In an aspect of the present invention, there is provided an antibacterial formulation comprising: i) an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2; and ii) at least one cosmetically suitable carrier.
[007] In another aspect of the present invention, there is provided a process for preparing the antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2, said process comprising steps of: a) obtaining thymol; b) obtaining undecanoic acid; and c) contacting thymol with undecanoic acid to obtain the composition. [008] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] The detailed description is described with reference to the accompanying
figures. The same numbers are used throughout the drawings to reference like
features and components.
[0010] Figure 1 illustrates the determination of MIC of thymol and undecanoic
acid against S. epidermidis, in accordance with an implementation of the present
subject matter.

[0011] Figure 2 illustrates the determination of MIC of zinc oxide and salicylic
acid against S. epidermidis, in accordance with an implementation of the present
subject matter.
[0012] Figure 3 illustrates the determination of degree of synergism between zinc
oxide and salicylic acid using checkerboard agar dilution assay, in accordance with
an implementation of the present subject matter.
[0013] Figure 4 illustrates images of petriplates of CFU assay for the assessment of
anti-bacterial activity of thymol (T); undecanoic acid (UA) and their synergistic
combinations against S. epidermidis, in accordance with an implementation of the
present subject matter.
[0014] Figure 5 illustrates log reduction of S. epidermidis growth upon treatment
with T and UA and their combinations, in accordance with an implementation of
the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Those skilled in the art will be aware that the present disclosure is subject to
variations and modifications other than those specifically described. It is to be
understood that the present disclosure includes all such variations and
modifications. The disclosure also includes all such steps, features, compositions,
and compounds referred to or indicated in this specification, individually or
collectively, and any and all combinations of any or more of such steps or features.
Definitions
[0016] For convenience, before further description of the present disclosure,
certain terms employed in the specification, and examples are delineated here.
These definitions should be read in the light of the remainder of the disclosure and
understood as by a person of skill in the art. The terms used herein have the
meanings recognized and known to those of skill in the art, however, for
convenience and completeness, particular terms and their meanings are set forth
below.
[0017] The articles “a”, “an” and “the” are used to refer to one or to more than one
(i.e., to at least one) of the grammatical object of the article.

[0018] The terms “comprise” and “comprising” are used in the inclusive, open
sense, meaning that additional elements may be included. It is not intended to be
construed as “consists of only”.
[0019] Throughout this specification, unless the context requires otherwise the
word “comprise”, and variations such as “comprises” and “comprising”, will be
understood to imply the inclusion of a stated element or step or group of element or
steps but not the exclusion of any other element or step or group of element or
steps.
[0020] The term “including” is used to mean “including but not limited to”.
“Including” and “including but not limited to” are used interchangeably.
[0021] The term ‘MIC’ refers to minimum inhibitory concentration. MIC is the
lowest concentration of an antimicrobial (like an antifungal, antibiotic or
bacteriostatic) drug that will inhibit the visible growth of a microorganism after
overnight incubation.
[0022] The term ‘CFU’ refers to colony forming unit. CFU is a unit used to
estimate the number of viable bacteria or fungal cells in a sample.
[0023] The term “liquid cleansing product” include shower gel, face wash, body
wash, hand wash, and paste. It is apparent that numerous other forms and
modifications of the liquid cleansing product will be obvious to those skilled in the
art and generally should be construed to cover all such obvious forms and
modifications which are within the true spirit and scope of the present disclosure.
[0024] The term “solid cleansing products” include cleansing bars, and films. It is
apparent that numerous other forms and modifications of the solid cleansing
product will be obvious to those skilled in the art and generally should be construed
to cover all such obvious forms and modifications which are within the true spirit
and scope of the present disclosure.
[0025] Ratios, concentrations, amounts, and other numerical data may be presented
herein in a range format. It is to be understood that such range format is used
merely for convenience and brevity and should be interpreted flexibly to include
not only the numerical values explicitly recited as the limits of the range, but also
to include all the individual numerical values or sub-ranges encompassed within

that range as if each numerical value and sub-range is explicitly recited. For example, a temperature ranges of about 22-28 °C should be interpreted to include not only the explicitly recited limits of about 22 °C to about 28 °C, but also to include sub-ranges, such as 22-25 °C, 25-28 °C, and so forth, as well as individual amounts, including fractional amounts, within the specified ranges, such as 22.2 °C, and 27.5 °C, for example.
[0026] The term “at least one” is used to mean one or more and thus includes individual components as well as mixtures/combinations.
[0027] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.
[0028] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally-equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.
[0029] As mentioned previously, prickly heat is a common disorder and most common medication utilizes zinc-based compounds to combat the bacterial pathogen responsible for the condition. Herbal or natural combinations are effective in providing effective relief while being non-toxic. However, herbal compositions addressing this problem suffer from cost-ineffectiveness. The present disclosure aims to solve the said problem by using a synergistic combination of thymol and undecanoic acid.
[0030] In an embodiment of the present invention, there is provided an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2. In another embodiment of the present disclosure, thymol to undecanoic acid weight ratio is in the range of 1:0.21 – 1:19. In yet another embodiment of the present disclosure, thymol to undecanoic acid weight ratio is in the range of 1:0.23 – 1:15.

[0031] In an embodiment of the present disclosure, there is provided an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is 1:0.25.
[0032] In an embodiment of the present disclosure, there is provided an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is 1:0.5.
[0033] In an embodiment of the present disclosure, there is provided an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is 1:1.
[0034] In an embodiment of the present disclosure, there is provided an antibacterial formulation comprising: i) an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2; ii) at least one cosmetically suitable carrier.
[0035] In an embodiment of the present disclosure, there is provided an antibacterial formulation as described herein, wherein the at least one cosmetically suitable carrier comprises additives selected from the group consisting of diluent, anti-caking agent, absorbent, skin protectant, viscosity modifier, opacifying agent, preservative, skin conditioning agent, cooling agent, odour enhancer, hydrophilic polymer, UV stabilizer, pH adjusting agent, chelating agent, deodorant, perfumes, antimicrobial, antioxidant, humectant, conditioning ingredients, propellants, salts, colorants, dyes, and combinations thereof. A list of additives has been provided, however the provided list is not be considered exhaustive and other known additives may be considered to fall within scope of the present disclosure. [0036] In an embodiment of the present disclosure, there is provided an antibacterial composition comprising: a) thymol having a weight percentage in the range of 0.00256 – 0.0256% with respect to the formulation; and b) undecanoic acid having a weight percentage in the range of 0.00128 – 0.0128% with respect to the formulation, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2. In another embodiment of the present disclosure, the composition comprises: a) thymol having a weight percentage in the range of 0.005 – 0.02% with respect to the composition; and b) undecanoic acid having a weight

percentage in the range of 0.002 – 0.01% with respect to the composition. In yet another embodiment of the present disclosure, the composition comprises: a) thymol having a weight percentage in the range of 0.01 – 0.02% with respect to the composition; and b) undecanoic acid having a weight percentage in the range of 0.005 – 0.01% with respect to the composition.
[0037] In an embodiment of the present disclosure, there is provided an antibacterial formulation comprising: a) thymol having a weight percentage in the range of 0.00256 – 0.0256% with respect to the formulation; b) undecanoic acid having a weight percentage in the range of 0.00128 – 0.0128% with respect to the formulation; and c) at least one cosmetically suitable carrier, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2.
[0038] In an embodiment of the present disclosure, there is provided an antibacterial formulation comprising: a) thymol having a weight percentage in the range of 0.00256 – 0.0256% with respect to the formulation; b) undecanoic acid having a weight percentage in the range of 0.00128 – 0.0128% with respect to the formulation; c) anti-caking agent having a weight percentage in the range of 60 – 70% with respect to the formulation; d) absorbent having a weight percentage in the range of 10 – 15% with respect to the formulation; e) skin protectant having a weight percentage in the range of 10 – 15% with respect to the formulation; f) viscosity modifiers having a weight percentage in the range of 0 – 20% with respect to the formulation; g) opacifying agent having a weight percentage in the range of 0 – 10% with respect to the formulation; h) preservative having a weight percentage in the range of 0 – 5% with respect to the formulation; i) skin conditioning agent having a weight percentage in the range of 0 – 1.5% with respect to the formulation; j) cooling agent having a weight percentage in the range of 0 – 2% with respect to the formulation; k) odour enhancer having a weight percentage in the range of 0.5 – 3% with respect to the formulation; l) perfume having a weight percentage in the range of 0.5 – 30% with respect to the formulation; m) antioxidant having a weight percentage in the range of 0.001 – 5% with respect to the formulation; and n) chelating agent having a weight percentage

in the range of 0.001 – 0.2% with respect to the formulation, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2.
[0039] In an embodiment of the present disclosure, there is provided an antibacterial formulation as described herein, wherein a) anti-caking agent is talc; b) absorbent is starch; c) skin protectant is selected without limitation from the group consisting of zinc oxide, zinc carbonate, and combinations thereof; d) viscosity modifier is selected without limitation from the group consisting of aluminium starch octenylsuccinate, crosslinked polyacrylate polymers, carboxylic acid polymers, polyacrylamide polymers, acrylic acid/ethyl acrylate copolymers, carboxyvinyl polymers, polyalkenyl polyether crosslinked polymer of acrylic acid crosslinked, and mixtures thereof; e) opacifying agent is selected without limitation from the group consisting of titanium dioxide, diatomaceous earth, calcium carbonate, magnesium carbonate, and combinations thereof; f) preservative is selected without limitation from the group consisting of boric acid, capryloyl salicylic acid, and combinations thereof; g) skin conditioning agent is selected without limitation from the group consisting of salicylic acid, allantoin, calcium salicylate, magnesium salicylate, potassium salicylate, sodium salicylate, panthenol, panthetine, pantotheine, panthenyl ethyl ether, and combinations thereof; h) cooling agent is selected without limitation from the group consisting of menthol, trimethyl isopropyl butanamide, peppermint oil, and combinations thereof; i) odour enhancer is selected from known fragrances; j) perfume is selected without limitation from known fragrances; k) hydrophilic polymer is selected from group consisting of polyethylene glycols (PEGs), polyvinylpyrrolidones (PVP), hydroxypropyl methylcellulose (HPMC), poloxamers, and combinations thereof; l) UV stabilizer is selected without limitation from group consisting of benzophenone-3 and other known UV stabilizers in the art; m) antioxidants is selected without limitation from group consisting of tocopheryl acetate, propyl, octyl and dodecyl esters of gallic acid, butylated hydroxyanisole (BHA, usually purchased as a mixture of ortho and meta isomers), butylated hydroxytoluene (BHT) , nordihydroguaiaretic acid, Oxynex (Oxynex ST liquid is a mixture of diethylhexyl syringyliden-emalonate and caprylic/capric triglyceride), vitamin A,

vitamin E, vitamin C, and other known antioxidants in the art; n) preservative is selected without limitation from group consisting of phenoxyethanol, benzyl alcohol, methyl paraben, propyl paraben, and combinations thereof; o) pH adjusting agent is selected without limitation from group consisting of lactic acid, citric acid, sodium citrate, succinic acid, phosphoric acid, sodium hydroxide, sodium carbonate, and combinations thereof; q) antimicrobial is selected without limitation from group consisting of farnesol, zinc phenolsulphonate, ethylhexylglycerin, and combinations thereof; r) humectant is selected without limitation from group consisting of tribehenin, glycerine, and combinations thereof; s) propellant is selected without limitation from group consisting of propane, isopropane, butane, isobutene, and combinations thereof; t) salt is selected without limitation from group consisting of potassium acetate, sodium chloride, and mixtures thereof; u) colorant and dye are selected from group consisting of known colorants in the art; v) chelating agent is selected without limitation from group consisting of ethylene diaminetetraacetic acid (EDTA) , EDTA disodium, calcium disodium edetate, EDTA trisodium, citric acid, EDTA tetrasodium, EDTA dipotassium, and combinations thereof; and w) diluent is selected from group consisting of water, alcohol, silicone, oil, and combinations thereof. In another embodiment of the present disclosure, the absorbent is a starch selected from corn starch, maize starch, and other known starches. In yet another embodiment of the present disclosure, the viscosity modifier is selected from well-known compounds as mentioned in Amjad et al., Carbomer Resins: Past, Present and Future Cosmetics & Toiletries 107 (1992), pp 81-85. In an alternate embodiment of the present disclosure, the viscosity modifier is selected from resins consisting of a colloidally water-soluble polyalkenyl polyether crosslinked polymer of acrylic acid crosslinked with from 0.75% to 2.00% of a crosslinking agent such as for example polyallyl sucrose or polyallyl pentaerythritol.
[0040] In an embodiment of the present disclosure, there is provided a process for preparing the antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2,

said process comprising steps of: a) obtaining thymol; b) obtaining undecanoic acid; and c) contacting thymol with undecanoic acid to obtain the composition. [0041] In an embodiment of the present disclosure, there is provided a process for preparing the antibacterial formulation comprising: i) an antibacterial composition comprising: a) thymol; and b) undecanoic acid, wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2; ii) and at least one cosmetically suitable carrier, said process comprising the steps of: a) contacting anti-caking agent, absorbent and skin protectant to obtain a first mixture; b) contacting thymol, undecanoic acid, odour enhancer, viscosity increasing agent, opacifying agent, preservative, skin conditioning agent, cooling agent with first mixture to obtain a second mixture; and c) processing the second mixture to obtain the formulation. [0042] In an embodiment of the present disclosure, there is provided a process as described herein, wherein contacting the anti-caking agent, the absorbent and the skin protectant is carried out at a temperature in the range of 22 - 28 °C at a stirring speed in the range of 20 - 40 rpm for a period in the range of 10 - 120 minutes to obtain a first mixture. In another embodiment of the present disclosure, contacting the anti-caking agent, the absorbent and the skin protectant is carried out at a temperature in the range of 23 - 27 °C at a stirring speed in the range of 25 - 35 rpm for a period in the range of 15 - 115 minutes to obtain a first mixture. In yet another embodiment of the present disclosure, contacting the anti-caking agent, the absorbent and the skin protectant is carried out at a temperature in the range of 24-26 °C at a stirring speed in the range of 27 - 32 rpm for a period in the range of 25 -100 minutes to obtain a first mixture.
[0043] In an embodiment of the present disclosure, there is provided a process as described herein, wherein contacting thymol, undecanoic acid, the odour enhancer, the viscosity increasing agent, the opacifying agent, the preservative, the skin conditioning agent, the cooling agent with first mixture is carried out at a temperature in the range of 22 - 28 °C at a stirring speed in the range of 20 - 40 rpm for a period in the range of 10 - 120 minutes to obtain a second mixture. In another embodiment of the present disclosure, contacting thymol, undecanoic acid, the odour enhancer, the viscosity increasing agent, the opacifying agent, the

preservative, the skin conditioning agent, the cooling agent with first mixture is carried out at a temperature in the range of 23 - 27 °C at a stirring speed in the range of 25 - 35 rpm for a period in the range of 15 - 115 minutes to obtain a second mixture. In yet another embodiment of the present disclosure, contacting thymol, undecanoic acid, the odour enhancer, the viscosity increasing agent, the opacifying agent, the preservative, the skin conditioning agent, the cooling agent with first mixture is carried out at a temperature in the range of 24 - 26 °C at a stirring speed in the range of 27 - 32 rpm for a period in the range of 25 - 100 minutes to obtain a second mixture.
[0044] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the processing the second mixture is carried out by filtration to obtain the antibacterial formulation. Filtration may be carried out using 60 mesh filter.
[0045] In an embodiment of the present disclosure, there is provided a formulation as described herein, wherein the formulation is dispensed in a form selected from powders, shower gels, sprays, emulsion, solution, antiseptics, patches, face washes, body washes, hand washes, pastes, liquid cleansing products, solid cleansing products, cleansing bars and films. In another embodiment of the present disclosure, the formulation is dispensed in the form of powder.
EXAMPLES [0046] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.

[0047] Prickly heat or miliaria is a serious condition that affects the population especially in hot and humid environment, as found in tropical countries. Though synthetic compositions are known for treating the condition, herbal formulations provide the possibility of solving the problem without the adverse side-effects of toxicity and drug-tolerance. The present disclosure aims to solve the said problem by using a synergistic herbal combination of thymol and undecanoic acid.
Example 1: Determination of minimal inhibitory concentration (MIC) of thymol and undecanoic acid against reference strain S. epidermidis (ATCC 35984)
[0048] Initially, the MIC of thymol (phytochemical, procured from Alfa Aesar, UK) and undecanoic acid (phytochemical, procured from Sigma Aldrich, USA) was evaluated using broth micro dilution assay in 96 well microtitre plate. One percent inoculum (v/v) of overnight culture of S. epidermidis was added to 200 µL of tryptic soy broth (TSB) supplemented with increasing concentrations (1 µg/mL – 512 µg/mL) of thymol and undecanoic acid separately. Wells devoid of treatment and wells containing only TSB was deliberated as control and blank, respectively. The assay was performed in triplicate. The plate was incubated at 37 °C for 24 h. Then, the optical density (OD) of the test samples was measured spectrometrically at 600 nm. MIC is determined as minimum concentration at which complete visible growth inhibition is observed. The percentage of growth inhibition was calculated using following formula
% of growth inhibition = (Control OD - Treated OD / Control OD) * 100. [0049] As is clear from result presented in Figure 1, thymol at 512 µg/mL and undecanoic acid at 256 µg/mL showed significant inhibition of growth (> 95%). Hence, MIC of thymol and undecanoic acid was determined as 512 µg/mL and 256 µg/mL, respectively. These values were important in establishing the individual contributions of the components towards inhibition of bacterial growth.
Example 2: Determination of minimal inhibitory concentration (MIC) of zinc oxide and salicylic acid against reference strain S. epidermidis (ATCC 35984) [0050] The current anti-miliaria products vastly employ chemicals such as salicylic acid and zinc oxide as antibacterial agents. Thus, in the current invention,

zinc oxide and salicylic acid were used as positive controls. Since, the present invention is focused to substitute the aforementioned antibacterial agents and or enhancing their activity in combination with phytochemicals, determination of MIC of zinc oxide and salicylic acid is mandatory. Owing to the insoluble nature of zinc oxide, MIC of zinc oxide and salicylic acid (Hi-Media, India) was determined using agar dilution method. Briefly, TSB agar plates supplemented with varying concentrations (1 to 2048 µg/mL) of zinc oxide and salicylic acid separately were prepared. Two microliter of overnight culture of S. epidermidis was used to inoculate a spot at center of the agar plates. Plain TSB agar plate and TSB agar plate devoid of treatment was deliberated as blank and control, respectively. Then, the plates were incubated at 37 °C for 24 h. After incubation, the plates were documented using high resolution charge-coupled device (CCD) camera (GelDoc XR+, Bio-Rad).
[0051] As is clear from result presented in Figure 2, zinc oxide and salicylic acid exhibited significant growth inhibition (> 90%) of S. epidermidis at the concentration of 2048 µg/mL. Hence, MIC of positive control samples, namely, zinc oxide and salicylic acid was determined as 2048 µg/mL.
Example 3: Checker board assay to determine the synergism between thymol and undecanoic acid
[0052] As the invention is directed towards the substitution of prevalently used natural antibacterial agents, appraising the synergistic effect of combination of phytochemicals (thymol + undecanoic acid) is essential. Thus, two-dimensional checkerboard assay was employed to assess the in vitro interactions between thymol + undecanoic acid using 96 well microtitre plate. Six different concentrations of each drug candidate were tested. Thymol at MIC (512 μg/mL) was added to the first column of 96 well microtitre plate, which was followed by the addition of two-fold lesser concentration of thymol for every consecutive column. Thus, the test concentrations of thymol were added in the range of 512 μg/mL to 0 μg/mL. Similarly, undecanoic acid at MIC (256 μg/mL) was added to the first row, which was diluted two-fold lesser concentration for every successive row. The last test concentration of each drug candidate was set at 0 μg/mL, so as to

examine the activity of individual drug candidate at various test concentrations in combination. Appropriate control, negative control and blank were considered. Each combination and independent dilutions were made in triplicate in 96 well microtitre plate as two separate experiments. The results of the experiment are provided below in Table 1. Table 1- Synergistic activity of thymol and undecanoic acid.

Concentration of thymol

512 µg/mL 256 µg/mL 128 µg/mL 64 µg/mL 32 µg/mL 0 µg/mL

256 µg/mL +
2 .0 1.5 +
1.25 +
1.125 +
1.0625 +

128 µg/mL 1.5 +
1.0 +
0.75 +
0.625 +
0.5625 -

64 µg/mL +
1.25 0.75 0.5 +
0.375 - -

32 µg/mL +
1.125 +
0.625 +
0.375 - - -

16 µg/mL +
1.0625 0.5625 - - - -

0 µg/mL + - - - - -
(+), (-) indicate the presence and absence of antibacterial activity, respectively. Inoculum control (IC) was found to be negative for all combinations. Values 10 indicate the FIC index.
Synergism between thymol and undecanoic acid was evaluated using the following formula: (Meletiadis et al., Antimicrob Agents Chemother. 2010, 54(2), 602-9)

FIC index = FICA + FICB
FICA =MIC of A in combination with B / MIC of A alone FICB=MIC of B in combination with A / MIC of B alone FIC index ≤ 0.5 ==synergistic 0.5 > FIC index < 2 == indifferent FIC index > 2 == Antagonistic FIC Thymol =0.25
FIC Undecanoic acid = 0.25FICIndex = FIC Thymol +FIC Undecanoic acid (0.25 + 0.25)
[0053] The synergistic antibacterial activity with more than 90% growth inhibition was found in 128 µg/mL+64 µg/mL; 128 µg/mL+32 µg/mL; 64 µg/mL+64 µg/mL combinations of thymol and undecanoic acid, respectively and the corresponding FIC indices of aforesaid active combinations were 0.5, 0.375 and 0.375. It was hence established from the results of Table 1 and Example 1, that the combination of thymol and undecanoic acid was found to inhibit bacterial growth at much lower concentrations than individual contributions, thus highlighting the synergy between the phytochemicals.
Example 4: Checker board assay to determine the synergism between zinc oxide and salicylic acid
[0054] Following the protocol as described in Example 3, the synergy between zinc oxide and salicylic acid was evaluated. The in vitro interactions between positive controls zinc oxide and salicylic acid were tested using agar dilution method. Totally six different concentrations were considered for each drug candidate. Initially, 36 petriplates were aligned in 6 X 6 arrays (i.e. 6 rows and 6 columns). Similar to broth dilution assay, TSB agar supplemented with zinc oxide at MIC (2048 μg/mL) was added to the first column, which was followed by addition of two-fold lesser concentration of zinc oxide to every consecutive column. Thus, the test concentrations of zinc oxide were added in the range of 2048 μg/mL to 0 μg/mL. In a similar way, salicylic acid at MIC (2048 μg/mL) was added to the first row, which was followed by the addition of two-fold lesser concentrations to every consecutive row. The last concentration in agar dilution method was also set at 0 μg/mL, so as to examine the activity of individual drug

candidate at various test concentrations in combination. The combination of zinc oxide and salicylic acid was made using agar dilution method. Two microliter of overnight culture was used to inoculate a spot at the center of the agar plates and incubated at 37 °C for 24 h. After incubation, the plates were documented using high resolution CCD camera (GelDoc XR+, Bio-Rad). The results are presented in Figure 3.
[0055] The synergistic antibacterial activity with more than 85% of growth inhibition of S. epidermidis was observed in 512 µg/mL + 512 µg/mL of zinc oxide and salicylic acid combination. The corresponding FIC index is 0.5. Moreover, the synergistic concentration of zinc oxide and salicylic acid combination was found to be approximately four times more than that of working synergistic concentrations of thymol and undecanoic acid. Thus, the proficient synergistic antibacterial activity of phytochemical combination than chemical based antibacterial agents is verified. The experimentation helps establish that the synergistic phytochemical combination of thymol and undecanoic acid can be used as an effective substitute for prevalently used antibacterial agents, which are known to pose certain toxic effects at their effectual concentration.
Example 5: Checker board assay to determine the in vitro interactions between phytochemicals
[0056] In order to establish ability of other phytochemical combinations to inhibit S. epidermidis similar checker board assays were performed in a manner as described in Example 3. Specifically, thymol and undecanoic acid were tested in combination with alternate phytochemicals such as eugenol and berberine via the checkerboard assay. Initially, the minimum inhibitory concentration (MIC) of phytochemicals namely eugenol, thymol, berberine and undecanoic acid was determined at increasing concentrations (1 to 1024 μg/mL) against Staphylococcus epidermidis (ATCC 35984) using microbroth dilution method as described earlier in Example 1. Eugenol at 1024 µg/mL, thymol at 512 µg/mL, berberine at 256 µg/mL and Undecanoic acid at 256 µg/mL showed significant inhibition of growth (> 95%). Hence, MIC of eugenol, thymol, berberine and undecanoic acid was determined as 1024 µg/mL, 512 µg/mL, 256 µg/mL and 256 µg/mL, respectively.

[0057] Further, two-dimensional checkerboard assay was employed to assess the in vitro interactions between eugenol + thymol, eugenol + undecanoic acid and berberine + undecanoic acid. Initially, the interactions between eugenol and thymol were evaluated using 96 well microtitre plate. Six different concentrations of each drug candidate were tested. Eugenol at MIC (1024 μg/mL) was added to the first column of 96 well microtitre plate, which was followed by the addition of two-fold lesser concentration of eugenol for every consecutive column. Thus, the test concentrations of eugenol were added in the range of 1024 μg/mL to 0 μg/mL. Similarly, Thymol at MIC (512 μg/mL) was added to the first row, which was diluted two-fold lesser concentration for every successive row. The combination of two phytochemicals was accomplished in checkerboard broth micro dilution assay as presented in Table 2 below. Appropriate control, negative control and blank were considered. Each combination and independent dilutions were made in triplicate in 96 well microtitre plate as two separate experiments. The other combinations pertaining to eugenol + undecanoic acid (see Table 3) and berberine + undecanoic acid (see Table 4) were tested in the similar manner.
Table 2: Synergistic activity of eugenol and thymol.
Concentration of eugenol

1024 µg/mL

512 µg/mL 256 µg/mL

128 µg/mL

64 µg/mL

0 µg/mL

512 µg/mL
256 µg/mL
128 µg/mL

+ + + + + +
2 .0 1.5 1.25 1.125 1.0625
+ + + - - -
1.5 1.0 0.75 0.625 0.5625
+ + - - - -

1.25 0.75 0.5 0.375

+ + -
64 µg/mL 1.125 0.625 0.375 - - -

+ -
32 µg/mL 1.0625 0.5625 - - - -

+ -
0 µg/mL - - - -
(+), (-) indicate the presence and absence of antibacterial activity, respectively. Inoculum control was found to be negative for all combinations. Values indicate the fractional inhibitory concentration (FIC) index.
Table 3: Synergistic activity of eugenol and undecanoic acid.
Concentration of eugenol

128 µg/mL 64 µg/mL
+
1.125 +
1.0625
+
0.625 -
0.5625

256 µg/mL
128 µg/mL

1024 µg/mL 512 µg/mL 256 µg/mL
+ + +
2 .0 1.5 1.25
+ + +
1.5 1.0 0.75

0 µg/mL
+
-

64 µg/mL +
1.25 +
0.75 -
0.5 -
0.375 - -

32 µg/mL +
1.125 +
0.625 -
0.375 - - -

16 µg/mL +
1.0625 +
0.5625 - - - -

0 µg/mL + - - - - -
(+), (-) indicate the presence and absence of antibacterial activity, respectively. Inoculum control was found to be negative for all combinations. Values indicate the fractional inhibitory concentration (FIC) index.
Table 4: Synergistic activity of berberine and undecanoic acid.

Concentration of berberine
256 µg/mL 128 µg/mL 64 µg/mL 32 µg/mL 16 µg/mL 0 µg/mL

256 µg/mL +
2 .0 +
1.5 +
1.25 +
1.125 +
1.0625 +

128 µg/mL +
1.5 +
1.0 +
0.75 -
0.625 -
0.5625 -

64 µg/mL +
1.25 +
0.75 -
0.5 -
0.375 - -

32 µg/mL +
1.125 -
0.625 -
0.375 - - -

16 µg/mL +
1.0625 -
0.5625 - - - -

0 µg/mL + - - - - -
(+), (-) indicate the presence and absence of antibacterial activity, respectively. Inoculum control was found to be negative for all combinations. Values indicate the FIC index.
[0058] Eugenol + thymol, eugenol + undecanoic acid and berberine + undecanoic acid combinations did not reveal inhibition at any concentration (Tables 2, 3 and 4), which clearly shows that not all antibacterial (phytochemicals) combinations are active against S. epidermidis. In contrast, Table 1 clearly reveals synergistic combinations, thus highlighting the experimental effort involved in identifying a suitable combination.
Example 6: CFU assay
[0059] Further to the checkerboard assays mentioned above in Examples 3, 4 and 5, the antibacterial activity of synergistic combinations of thymol and undecanoic acid was further confirmed using colony forming unit (CFU) assay. Working synergistic combinations (as revealed in Table 1) of thymol and undecanoic acid (128 µg/mL+64 µg/mL; 128 µg/mL+32 µg/mL; 64 µg/mL+64 µg/mL) and individual drug candidates at synergistic combinations (128 µg/mL, 64 µg/mL, 32

µg/mL) were added separately to the tubes containing 1 mL of TSB. Tubes without any treatment and tubes containing TSB alone were deliberated as control and blank, respectively. All tubes were inoculated with 1% v/v of overnight culture of S. epidermidis and incubated at 37 °C for 24 h in shaker incubator (160 rpm). After incubation, the cells were harvested by centrifugation (8000 rpm for 10 min) and subsequently suspended in 1 mL of phosphate buffered saline (PBS). The cell suspensions were serially diluted and 100 µL of 10-6 dilution of each sample was spread over the TSB agar plates. TSB agar plate spread with 100 µL of PBS was considered as blank. The plates were incubated overnight at 37 °C for 24 h. Then, the number of colonies in each plate was counted manually and CFU/mL was calculated. The log reduction was calculated using the following formula:
Log reduction = Log (CFU/mLControl) – Log (CFU/mLTreated)
[0060] Figure 4 shows images of petriplates of CFU assay used for the assessment of anti-bacterial activity of thymol (T); undecanoic acid (UA) and their synergistic combinations against S. epidermidis. It can be observed that the synergistic combinations (as revealed in Table 1) do not show any colony growth (see Figure 4). The CFU assay further affirmed that the synergistic combinations of T+UA inhibited the growth of S. epidermidis cells to a greater extent than that of the individual T and UA (Figure 1 and 4). In addition, the log reduction of S. epidermidis growth upon treatment with individual T and UA and their combinations was calculated and depicted as a bar chart in Figure 5. The result reveals that the synergistic combinations of T+UA exhibited more than one log reduction of S. epidermidis growth (~ 99 % of growth inhibition) when compared to that of individual T and UA, which showed less than one log reduction. In conclusion, the obtained results confirmed the anti-miliaria potential of synergistic T+UA combinations.
Example 7: Formulation comprising thymol and undecanoic acid
[0061] The disclosure has been illustrated with a working example, which is
intended to explain the working template for the commercial application of

synergistic combination of T and UA used in the present disclosure. However, this
working example does not imply any limitations on the scope of the present
disclosure. The ingredients of anti-miliaria or prickly heat powder comprising
synergistic combination of T+UA is mentioned in Table 5 along with the weight
percentages.
Table 5- Ingredients used in the anti-miliaria or prickly heat powder preparation
and their respective function(s).

S.No. Name of ingredient % weight Functionality
1. Talc 60 – 70 or Q.S. to 100 Anti-caking agent
2. Maize starch or corn starch 10 – 15 Absorbent
3. Zinc oxide 10 – 15 Skin protectant
4. Aluminium starch octenylsuccinate 0 – 20 Viscosity modifier
5. Titanium dioxide 0 – 10 Opacifying agent
6. Boric acid 0 – 5 Preservative
7. Salicylic acid 0 – 1.5 Skin conditioning agent
8. Menthol 0 – 2 Cooling agent
9. Thymol 0.00256 – 0.0256 Active
10. Undecanoic acid 0.00128 – 0.0128 Active
11. Fragrance 0.5 – 3 Odour enhancer
[0062] Process for preparation of the formulation comprises the following steps: (a) talc, maize or corn starch and zinc oxide were continuously mixed in a blender

at a temperature in the range of 22 - 28 °C at a stirring speed in the range of 20 - 40 rpm for a period in the range of 10 - 120 minutes until a homogenous mixture (first mixture) is obtained; (b) synergistic combination of T+UA, odour enhancer such as fragrances and other optional ingredients such as aluminium starch octenylsuccinate, titanium dioxide, boric acid, salicylic acid and menthol were added to the first mixture at a temperature in the range of 22 - 28 °C for a period in the range of 10 - 120 minutes under continuous agitation (20-40 rpm) to obtain a bulk (second mixture); (c) Then, the bulk (second mixture) was processed by passing through a 60 mesh size filter to obtain the formulation.
Advantages of the present disclosure:
[0063] The present disclosure reveals a composition comprising herbal ingredients that is effective against S. epidermidis which is the primary causal agent in prickly heat rash or Miliaria. The composition comprising thymol to undecanoic acid in a ratio range of 1:0.2 – 1:2 was found to synergistically inhibit said bacteria. The combination was found to be more effective than commercial synthetic antibacterial agents such as zinc oxide and salicylic acid. The composition can be easily adapted to obtain useful commercial formulations such as powders. Furthermore, an example for preparation of a powder formulation has been provided. Said process is can be conveniently carried out at room temperature.

I/We Claim:
1. An antibacterial composition comprising:
a) thymol; and
b) undecanoic acid,
wherein thymol to undecanoic acid weight ratio is in the range of 1:0.2 – 1:2.
2. The antibacterial composition as claimed in claim 1, wherein thymol to undecanoic acid weight ratio is 1:0.25.
3. The antibacterial composition as claimed in claim 1, wherein thymol to undecanoic acid weight ratio is 1:0.5.
4. The antibacterial composition as claimed in claim 1, wherein thymol to undecanoic acid weight ratio is 1:1.
5. An antibacterial formulation comprising:

a) an antibacterial composition as claimed in any of the claims 1-4; and
b) at least one cosmetically suitable carrier.

6. The antibacterial formulation as claimed in claim 5, wherein the at least one cosmetically suitable carrier comprises additives selected from the group consisting of diluent, anti-caking agent, absorbent, skin protectant, viscosity modifier, opacifying agent, preservative, skin conditioning agent, cooling agent, odour enhancer, hydrophilic polymer, UV stabilizer, pH adjusting agent, chelating agent, deodorant, perfumes, antimicrobial, antioxidant, humectant, conditioning ingredients, propellants, salts, colorants, dyes, and combinations thereof.
7. A process for preparing the composition as claimed in claim 1, said process comprising the steps of: a) obtaining thymol; b) obtaining undecanoic acid; and c) contacting thymol with undecanoic acid to obtain the composition.
8. A process for preparing the formulation as claimed in any of the claims 5-6, said process comprising the steps of: a) contacting anti caking agent, absorbent and skin protectant to obtain a first mixture; b) contacting thymol, undecanoic acid, odour enhancer, viscosity increasing agent, opacifying agent, preservative, skin conditioning agent, cooling agent with

first mixture to obtain a second mixture; and c) processing the second mixture to obtain the formulation.
9. The process as claimed in claim 8, wherein contacting the anti-caking agent, the absorbent and the skin protectant is carried out at a temperature in the range of 22 - 28 °C at a stirring speed in the range of 20 - 40 rpm for a period in the range of 10 - 120 minutes to obtain a first mixture.
10. The process as claimed in claim 8, wherein contacting thymol, undecanoic acid, the odour enhancer, the viscosity increasing agent, the opacifying agent, the preservative, the skin conditioning agent, the cooling agent with first mixture is carried out at a temperature in the range of 22 - 28 °C at a stirring speed in the range of 20 - 40 rpm for a period in the range of 10 -120 minutes to obtain a second mixture.
11. The formulation as claimed in any of the claims 5-6, is dispensed in a form selected from powders, sprays, emulsion, solution, antiseptics, patches, face washes, body washes, hand washes, pastes, liquid cleansing product, solid cleansing products, cleansing bars and films.