Skin lightening composition

Abstract

The present invention relates to personal care compositions that provide a uniform and bright complexion. This is achieved by comprising a resorcinol derivative in combination with an oil derived from moringa seeds in a cosmetically acceptable carrier in a topical composition.

Description

Technical Field

[0001] The present invention relates to personal care compositions that provide a bright and even skin tone. Background Art

[0002] Most people consider the appearance of the skin, especially on the face, as one of the key indicators of their own beauty and health. Thus, many people desire to have a bright, flawless, and even skin tone. The degree and uniformity of skin pigmentation are affected by factors such as age, hormonal changes, the occurrence of acne, and exposure to sunlight and pollution. These can result in spots or freckles, hyperpigmentation on specific local areas of the skin, and dark circles under the eyes. Many people also believe that certain lifestyle factors such as hydration (the amount of water consumed), the type of food, and the quantity and quality of sleep also have an impact on the appearance of the skin, including dark circles under the eyes. Since people realize that changes such as living a healthier lifestyle may take a long time to even out the appearance of the skin, they rely on cosmetic solutions to provide a temporary solution for the blemishes on their skin. They also seek such products to reduce skin darkening caused by exposure to sunlight. To meet this demand, many attempts have been made to develop products that can reduce pigment production in melanocytes.

[0003] The inventors have worked in this field for a long time, have filed numerous patent applications, and have produced various cosmetic products on the market. In the present invention, they specifically sought a highly effective solution to the problem that can also be used as a general cosmetic product for delivering an even and bright skin tone, especially on exposed skin surfaces.

[0004] During the process of their extensive research on the factors and active substances that they understand affect pigmentation and their exploration of the human skin microbiome, two apparently unrelated fields, they unexpectedly found that the combination of the well-known skin brightening active substance, resorcinol derivatives, and the moringa oil fermented by skin commensal bacteria (which they found to be a suitable prebiotic for the skin microbiome) interact synergistically to deliver an even and bright skin tone. The oil from moringa has been safely used on the skin for a long time, thus providing a natural alternative to some chemically active substances that are considered highly irritating. To the knowledge of the inventors, such a combination of active substances was not previously known to deliver such a benefit.

[0005] Accordingly, an object of the present invention is to provide a solution to the problem of uneven skin appearance by delivering a topical composition that gives an even and brighter skin appearance.

[0006] Another object of the present invention is to provide such a solution that involves the inclusion of mild and known-to-be-safe active substances on the skin. Summary of the Invention

[0007] A first aspect of the present invention relates to a personal care composition comprising:

[0008] (a) Moringa oleifera seed oil;

[0009] (b) Substituted resorcinol; and

[0010] (c) A cosmetically acceptable carrier,

[0011] wherein the Moringa oleifera seed oil is fermented by skin symbiotic bacteria.

[0012] Another aspect of the present invention relates to a method for providing skin brightness, which comprises the step of applying the composition of the first aspect to the skin. Detailed Description

[0013] These and other aspects, features, and advantages will become apparent to those of ordinary skill in the art by reading the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention can be used in any other aspect of the present invention. The term "comprising" is intended to mean "including", but not necessarily "consisting of" or "constituted by". In other words, the listed steps or options need not be exhaustive. It should be noted that the examples given in the following description are intended to illustrate the present invention and are not intended to limit the present invention to these examples themselves. Similarly, unless otherwise specified, all percentages are weight / weight percentages; and can be abbreviated as 'wt%'. Except in the examples and comparative examples, or where otherwise clearly stated, all numerical values representing amounts of materials, reaction conditions, physical properties of materials, and / or uses in this specification and the claims should be understood to be modified by "about". Numerical ranges expressed in the form "x to y" should be understood to include x and y. When multiple preferred ranges for a particular feature are described in the format "x to y", it should be understood that all ranges combining different endpoints are also contemplated.

[0014] The compositions of the present invention are intended for personal care or cosmetic use and may also be referred to as personal care compositions or cosmetic compositions. As used herein, "personal care composition" refers to a composition for topical application, i.e., the outer surface of the human skin. Such compositions can be classified as leave-on or rinse-off and include any product applied to the human body for improving appearance, cleansing, odor control, or general aesthetics. The composition is preferably leave-on. The compositions of the present invention can be in the form of a liquid, lotion, cream, foam, stick, serum, essence, or gel. Preferred compositions include leave-on gels, lotions, serums, or creams, preferably in the form of a serum or cream. As used herein, "skin" is meant to include the skin on the face and body (such as the neck, chest, back, arms, underarms, hands, legs, and scalp), particularly the exposed portions thereof.

[0015] The present invention provides a personal care composition comprising moringa seed oil; a substituted resorcinol; and a cosmetically acceptable carrier, wherein the moringa seed oil is fermented by a skin symbiont (the composition).

[0016] The genus Moringa includes about 14 species of plants (among which especially Moringa peregrina, M. aptera, M. concanensis, M. drouhardii, M. hildebrandtii, and M. longituba), and among them Moringa pterygosperma is the best known. The seeds of Moringa are characterized by the presence of oil, the content of which can vary from 20% to 80% depending on the species and maturity of the seeds. For the species Moringa oleifera, the oil content mentioned in the literature ranges from 21% to 34%.

[0017] Comparison of the oils of the seeds of Moringa oleifera, Moringa peregrina, Moringa concanensis and Moringa drouhardii shows very similar fatty acid contents, and these oils all mainly have oleic acid and some saturated fatty acids. Preferably, the oil is extracted from the seeds of at least one of Moringa oleifera, Moringa pterygosperma, Moringa peregrina, Moringa concanensis or Moringa drouhardii. Particularly preferably, the oil is extracted from Moringa oleifera or Moringa pterygosperma. Preferably, the oil content in the composition of the present invention is 0.015% to 0.4 wt%. The oil is rich in oleic acid-type fatty acids. Particularly preferably, the Moringa oleifera oil used in the present invention contains 60% to 80% oleic acid and 2% to 10% palmitic acid.

[0018] In Int. J. Mol. Sci. 2016, 17, 2141; doi:10.3390 / ijms17122141, Leone et al. have published a literature review on the components of Moringa oil.

[0019] Preferably, the oil is extracted almost entirely by solvent extraction (especially using n-hexane, more preferably at an extraction ratio of 3:1 to 8:1 by weight). Alternatively, the oil is extracted by cold pressing extraction. It is reported that about 69% (average) of the total oil contained in the seeds can be extracted by cold pressing.

[0020] The composition comprises moringa seed oil fermented by skin commensal bacteria. Preferably, such commensal bacteria include one or more of Staphylococcus epidermidis, Staphylococcus hominis, Cutibacterium acnes, Micrococcus luteus, Corynebacterium species such as Corynebacterium xerosis, Corynebacterium pseudogenitalium, and Corynebacterium tuberculostearicum. The moringa seed oil preferably accounts for 0.01 to 1 wt%, preferably 0.05 to 1 wt%, preferably 0.1 to 1 wt%, preferably 0.5 to 1 wt% of the weight of the composition. It is expected that the benefits of the present invention can be obtained even by applying the (unfermented) moringa seed oil in the composition of the present invention to the skin. When applied in this way, it is expected that the moringa seed oil will interact with the above-mentioned commensal bacteria such as Staphylococcus epidermidis that are normally present on the skin to ferment the moringa seed oil in situ on the skin to deliver the same benefits as those obtained when the moringa seed oil is fermented ex-situ. Therefore, the moringa seed oil used in the composition can be fermented by skin commensal bacteria ex-situ or in situ.

[0021] Resorcinol is a dihydroxyphenol compound (i.e., 1,3-dihydroxybenzene), which is characterized by alcohol groups (-OH) at the 1 and 3 positions. The chemical structure of resorcinols can be modified to form substituted resorcinols, which are characterized by at least one substituent at the 2, 4, 5, or 6 position. Preferably, the resorcinol comprises at least one substituent comprising 2 to 11 carbon atoms, preferably 2 to 8 carbon atoms, and most preferably 2 to 6 carbon atoms. Particularly preferably, at least one substituent comprises an alkyl group. The resorcinol compounds contained in the cosmetic composition of the present invention are oil-soluble substituted resorcinols.

[0022] Preferably, the resorcinol in the cosmetic composition is substituted only at the 4-position, preferably by an alkyl group. Exemplary but non-limiting examples of substituted resorcinols include 4-ethylresorcinol, 4-hexylresorcinol, 4-phenethylresorcinol, 4-cyclopentylresorcinol, 4-cyclohexylresorcinol, 4-octylresorcinol, and mixtures thereof. More preferred substituted resorcinols for use in the present invention are one or both of 4-ethylresorcinol and 4-hexylresorcinol; most preferably 4-hexylresorcinol. The composition preferably contains from 0.00001 to 1%, preferably from 0.0001 to 1%, preferably from 0.001 to 1%, preferably from 0.01 to 1%, preferably from 0.1 to 0.5%, for example 0.25%, of the substituted resorcinol, including all ranges therein, by weight of the cosmetic composition.

[0023] One advantage of the present invention is that it has been found that by including fermented moringa seed oil as a natural material, preferably much lower amounts of synthetic active substances such as substituted resorcinols need to be included to achieve the same efficacy.

[0024] Without wishing to be bound by theory, the inventors believe that the combination of active substances exerts the benefits of the present invention by inhibiting the tyrosinase enzyme activity and its level in melanocytes.

[0025] The composition preferably contains an oil having a Hansen total solubility parameter (δ t ) value in the range of 16.5 to 22. Preferred oils may be selected from one or more of isopropyl myristate, isopropyl palmitate, caprylic / capric triglycerides, and benzyl alcohol. These oils are preferably included in an amount of 8 to 25 wt% by weight of the composition.

[0026] The composition of the present invention preferably contains an emulsifying polymer. The emulsifying polymer is preferably a swellable polymer powder made from pure acrylic monomers, or a mixture of acrylic monomers and methacrylic monomers, more preferably a polymer having the chemical name acrylate / C 10-30 alkyl acrylate cross-linked polymer, carbomer, or a mixture thereof. In one aspect, the polymer is a cross-linked or non-cross-linked homopolymer. In another aspect, the polymer is a cross-linked or non-cross-linked copolymer. The emulsifying polymer is multifunctional and is capable of emulsifying, stabilizing, and / or increasing the viscosity of the composition. Using the polymer emulsifier alone or in combination with other additional polymer emulsifiers is within the scope of the composition of the present invention. Exemplary but non-limiting acrylate / C 10-30Alkyl acrylate crosspolymer is commercially available from The Lubrizol Corporation under trade names such as PEMULEN TM TR-1, PEMULEN TM TR-2, PEMULEN TM EZ-4U, Ultrez 20, Ultrez 21, 1382 and ETD 2020. Desired carbomers for use in the compositions of the present invention include Ultrez 10 and 980, both sold by The Lubrizol Corporation. The emulsifying polymer is included in the cosmetic composition in an amount of from 0.01 to 5 wt%, preferably from 0.02 to 4 wt%, more preferably from 0.03 to 3 wt% based on the total weight of the composition. Even more preferably, the polymer is included in the cosmetic composition in an amount of from 0.04 to 2 wt%, most preferably from 0.05 to 1 wt% based on the weight of the cosmetic composition, including all ranges therein.

[0027] The compositions of the present invention may additionally comprise one or more of a sunscreen, a light stabilizer, a skin brightener, a wrinkle reducer, and a colorant.

[0028] The composition may additionally comprise an organic sunscreen selected from one or both of the classes of UVA sunscreens and UVB sunscreens. Sunscreens include those materials commonly used to block ultraviolet light. Exemplary compounds are derivatives of PABA, cinnamates, and salicylates. For example, avobenzophenone (Parsol )), octyl methoxycinnamate, and 2-hydroxy-4-methoxybenzophenone (also known as oxybenzone) may be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxybenzophenone are commercially available under the trademarks Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen used in the composition may vary depending on the degree of protection against solar UV radiation desired. Additives that reflect or scatter sunlight may also be used. These additives include oxides such as zinc oxide and titanium dioxide.

[0029] The composition of the present invention may additionally comprise a cosmetically acceptable carrier, which can be used as a diluent, dispersant, and / or carrier for the active substances in the composition to facilitate their distribution when the composition is applied to the skin. The cosmetically acceptable carrier suitable for use in the present invention can be aqueous, anhydrous, or an emulsion; preferably aqueous or an emulsion, where the emulsion is a water-in-oil or oil-in-water emulsion, with the latter being most preferred. When present, water generally constitutes the balance of the composition. Preferably, water is present at a concentration of 5 to 99 wt%, more preferably 20 to 80 wt%, still more preferably 40 to 80 wt% based on the weight of the composition.

[0030] The composition of the present invention can be delivered in the form of a slurry, cream, lotion, or gel, preferably in the form of a cream. For the solid form of the composition, the preferred form is a cream, and even more preferably a cream having a vanishing cream matrix. A vanishing cream matrix is one that contains 3 to 25 wt% of fatty acids. Optionally, the composition may contain 0.1 to 10 wt% of soap. When included, the fatty acids are preferably C10 to C22 fatty acids, more preferably C16 to C18 fatty acids. Most preferably, the fatty acid is stearic acid or palmitic acid or a mixture thereof, and the soap is preferably the potassium salt of the fatty acid mixture. The fatty acid is typically hystric acid, which is substantially (usually about 90 to 95%) a mixture of 45% stearic acid and 55% palmitic acid. The most preferred cream is a cream having 3 to 25 wt% of fatty acids and 0.1 to 10 wt% of soap.

[0031] Preferably, the composition comprises an emollient. Examples of emollients that can be used in leave-on compositions include stearyl alcohol, glyceryl monocastor oilate, mink oil, isopropyl isostearate, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecane-2-ol, isocetyl alcohol, eicosanol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethylpolysiloxane, din-butyl sebacate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, cocoa butter, corn oil, cottonseed oil, olive oil, palm kernel oil, rapeseed oil, safflower oil, evening primrose oil, soybean oil, sunflower oil, avocado oil, sesame seed oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohols, petrolatum, mineral oil, butyl myristate, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate, and mixtures thereof.

[0032] Preferably, the composition comprises a solvent. Examples of solvents that can be used in the composition include ethanol, isopropanol, acetone, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, and mixtures thereof. The composition may comprise a polyol, which may be selected from one or more of glycerol, 1,3 - butanediol, propylene glycol, 1,3 - propanediol, pentylene glycol, hexylene glycol, and sorbitol.

[0033] Preferably, the composition comprises a powder. Examples of powders that can be used in the composition include chalk, talc, bleaching earth, kaolin, starch, gum, colloidal silica, sodium polyacrylate, tetraalkyl and / or trialkyl aryl ammonium bentonite clays, chemically modified magnesium aluminum silicate, organically modified montmorillonite, hydrated aluminum silicate, pyrogenic silica, carboxyvinyl polymer, sodium carboxymethyl cellulose, ethylene glycol monostearate, and mixtures thereof.

[0034] Preferably, the composition comprises a preservative to prevent the growth of potentially harmful microorganisms. Examples of ingredients that can be used as preservatives in the composition include alkyl esters of p - hydroxybenzoic acid, hydantoin derivatives, propionates, and various quaternary ammonium compounds. More preferably, the ingredients that can be used as preservatives in the composition are sodium benzoate, iodopropynyl butyl carbamate, methylisothiazolinone, iodopropynylbutylcarbamate, phenoxyethanol, methylparaben, propylparaben, imidazolidinyl urea, sodium dehydroacetate, ethylhexylglycerin, benzyl alcohol, alkanediols, and mixtures thereof. When present in the composition, the preservative is preferably added in an amount of 0.001 to 5 wt%, more preferably 0.01 to 3 wt%, most preferably 0.02 to 2 wt%, and even most preferably 0.25 to 1.5 wt%.

[0035] Preferably, the composition comprises a series of other optionally present ingredients, which include antioxidants, binders, buffers, colorants, astringents, fragrances, opacifiers, conditioners, exfoliants, pH adjusters, skin sensates, skin soothers, and skin healers.

[0036] Within the scope of the present invention, the compositions claimed herein are eco-friendly and thus do not contain certain ingredients that are increasingly implicated in long-term environmental damage. Thus, one aspect of the present invention relates to compositions that are preferably free of sulphate surfactants. Another aspect relates to the compositions herein that are preferably free of preservatives. Yet another aspect relates to compositions that are preferably free of acrylate polymers. Compositions that are preferably free of titanium dioxide are also within the scope of the present invention. Green (i.e., biodegradable chelating agents are preferred) are used in such compositions, i.e., the compositions are preferably free of conventional chelating agents such as EDTA. According to the present invention, "free of" a particular ingredient preferably means that the composition contains less than 0.1 wt%, preferably less than 0.05 wt%, and even more preferably less than 0.01 wt% of the ingredient, based on the weight of the composition. They are optimally absent from the composition.

[0037] The packaging for the compositions of the present invention can be a patch, bottle, tube, roll-on applicator, propellant-driven aerosol device, squeeze container, or capped jar.

[0038] In another aspect, the present invention relates to the use of the compositions according to the present invention for skin brightening. Preferably, the use is non-therapeutic or cosmetic in nature.

[0039] In yet another aspect, the present invention relates to a method of providing brightness or an even skin tone to a human skin, the method comprising the step of applying a composition according to the present invention to the skin. Preferably, the method is non-therapeutic or cosmetic in nature.

[0040] In yet another aspect of the present invention, there is provided a method of providing microbiome benefits to the skin, the method comprising the step of applying a composition according to the present invention to the skin. Preferably, the method is non-therapeutic or cosmetic in nature.

[0041] The present invention will now be illustrated by the following non-limiting examples.

[0042] Examples

[0043] Examples A to K, 1 to 4: % black pigment reduction achieved by the combination of active substances according to the invention relative to the control amount

[0044] Various samples containing the active substance were prepared and the % melanin reduction was measured. The protocol for measuring this melanin reduction is summarized below:

[0045] A co-culture of HaCat keratinocytes and primary human melanocytes was mixed at 40,000 each (1:1 ratio) in a 1:1 mixture of their respective media in 1 ml and seeded into each well of a 12-well plate accordingly. After 24 hours, the cultures were treated with various concentrations of the test material shown in Table 1 and kept static for an additional 72 hours. A comparative vehicle control was also established simultaneously. For melanin assessment at the end of the 72-hour incubation, the calcein AM method was first used to determine cell viability. Briefly, the used media was removed and the cells were washed once with 0.4 ml of 1×PBS / well. 1 μM of calcein-AM in fresh PBS buffer was added to each well, including control wells without cells. The plate was covered with aluminum foil and incubated in a CO2 incubator at 37 °C for 30 minutes. Calcein fluorescence (excitation at 490 nm and emission at 520 nm) was measured in a TECAN M1000 microplate reader. The culture wells were drained and lysed using 1N NaOH containing 10% DMSO and placed in a shaking incubator at 60 °C for 1 hour. 100 μl of the supernatant was transferred to a 384-well plate and melanin was measured in a TECAN microplate reader (405 nm filter). Melanin content (MC) was expressed after correcting for cell number (MC / calcein) and represented as % melanin.

[0046] The following samples given in Table-1 were prepared and the % melanin reduction for each sample measured is also given in the table.

[0047] Table-1

[0048]

[0049] In the above table:

[0050] Moringa seed oil was from Naturex SA, France.

[0051] The moringa oil was fermented as described below.

[0052] Tryptic Soy Agar (TSA) was prepared and autoclaved. The TSA plates were poured and allowed to solidify, and then inoculated with Staphylococcus epidermidis (ATCC 12228) from a glycerol stock by streaking and incubated for 24 hours. Moringa oil was dissolved in DMSO and then added to autoclaved Tryptic Soy Broth (TSB) at the desired concentrations of 0.05% and 0.01%. A pure bacterial culture with an optical density of 0.3 was prepared and inoculated into autoclaved TSB with the said moringa oil and incubated in a shaking incubator at 120 rpm at 37 °C for 24 hours (in sample cups). After 24 hours of incubation, the optical density was measured to check for interference of the biological active agent in the growth of the said bacteria. The said culture was transferred to a centrifuge tube and centrifuged at 6500 rpm for 10 minutes. The supernatant was filter sterilized using a membrane filter, aliquoted into 1 ml and stored at -80 °C for testing on skin cell cultures.

[0053] The moringa oil samples fermented by Staphylococcus epidermidis were diluted 1:40 in the said keratinocyte + melanocyte medium mixture and then introduced into the said co-culture for melanin content determination.

[0054] The data in Table - 1 above shows that, compared to using 4-HR at a concentration of 0.0002% (Example - B), the composition according to the present invention (Example 1) provides a significantly superior reduction in melanin content. It has been found that using a concentration of 4-HR higher than 0.0002% (at the cellular level in in vitro experiments) results in cell viability problems. Another Example - 3 confirms the synergistic interaction between 4-HR and moringa seed oil.

[0055] It should be understood that the above experiments were conducted in in vitro assays. It is expected that the concentrations actually to be used for preparing compositions for topical use would be very different. Due to the following reasons affecting the concentration differences in the bulk, the concentrations actually to be used for preparing compositions for topical use can be of a much higher order of magnitude compared to the concentrations at the cellular level. The compositions can be formulated as emulsions or gels with a very large number of additional ingredients. The concentrations of the desired active agent in the oil phase and in the water phase are expected to be very different. They can also have very different physical and hydrodynamic properties, such as partition coefficients, diffusion rates, convective transport rates, rheological properties, etc. Therefore, it is expected that the concentrations to be used would be very different when formulated as compositions compared to the concentrations evaluated at the cellular level. Compared to the concentrations in in vitro experiments at the cellular level, the concentrations to be used when formulated as compositions are generally much higher, even 2 to 3 orders of magnitude higher.

Claims

1. A personal care composition comprising: (a) Moringa oleifera seed oil; (b) A substituted resorcinol; and (c) A cosmetically acceptable carrier, wherein the Moringa oleifera seed oil is fermented by skin commensal bacteria.

2. The composition according to claim 1, wherein, The substituted resorcinol includes one or more of 4-hexylresorcinol, 4-ethylresorcinol, 4-phenethylresorcinol, 4-cyclopentylresorcinol, 4-cyclohexylresorcinol, and 4-octylresorcinol.

3. The composition according to claim 2, wherein, The substituted resorcinol includes one or two of 4-hexylresorcinol and 4-ethylresorcinol, and preferably includes 4-hexylresorcinol.

4. The composition according to any one of the preceding claims, the composition comprising from 0.00001 to 1 wt% of the substituted resorcinol.

5. The composition according to any one of the preceding claims, wherein, The moringa seed oil contains 60 to 80% oleic acid and 2 to 10% palmitic acid.

6. The composition according to any one of the preceding claims, wherein, The skin commensal bacteria are one or more of Staphylococcus epidermidis, Staphylococcus hominis, Cutibacterium acnes, Micrococcus luteus, and Corynebacterium species.

7. The composition according to any one of the preceding claims, the composition comprising from 0.01 to 1 wt% of the Moringa oleifera seed oil.

8. The composition according to any one of the preceding claims, wherein, The cosmetically acceptable carrier includes an oil, which is preferably selected from one or more of isopropyl myristate, isopropyl palmitate, caprylic / capric triglycerides, and benzyl alcohol.

9. The composition according to any one of the preceding claims, wherein, The cosmetically acceptable carrier includes an emulsifying polymer selected from one or more of acrylate / C 10-30 alkyl acrylate crosslinked polymers, and carbomers, and the emulsifying polymer preferably accounts for 0.01 to 5 wt% of the weight of the composition.

10. The composition according to any one of the preceding claims, wherein, The composition is in the form of a slurry, cream, emulsion, or gel, preferably in the form of a slurry or cream.

11. A method of providing an even skin tone, comprising the step of applying the composition according to any one of the preceding claims to the skin.

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