WO2002041866A2

WO2002041866A2 - Cosmetic composition

Info

Publication number: WO2002041866A2
Application number: PCT/EP2001/013254
Authority: WO
Inventors: Robert Mark Donovan
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2000-11-24
Filing date: 2001-11-14
Publication date: 2002-05-30
Also published as: AU2002227928A1; WO2002041866A3; GB0028706D0

Abstract

A cosmetic method for treating aged, wrinkled and/or photodamaged skin is provided through topical application of a composition which comprises oxygenase enzymes and a skin care benefit agent.

Description

COSMETIC COMPOSITION

This invention relates to the use of oxygen scavenging enzymes such as oxygenases which do not generate radicals or hydrogen peroxide in (which herein includes on) the skin, and in particular dioxygenases, in the preparation of topical compositions for improving the condition and appearance of skin.

Skin is subject to deterioration through dermatological disorders, environmental abuse (wind, air conditioning, central heating) or through the normal aging process (chronoaging) which may be accelerated by exposure of skin to sun (photoaging). In recent years the demand for cosmetic compositions and cosmetic methods for improving the appearance and condition of skin has grown enormously.

Consumers are increasingly seeking "anti-aging" cosmetic products which treat or delay the visible signs of chronoaging and photoaging skin such as wrinkles, lines, sagging, hyperpigmentation and age spots.

Consumers also frequently seek other benefits from cosmetic products in addition to anti-aging. The concept of "sensitive skin" has also raised the consumer demand for cosmetic products which improve the appearance and condition of sensitive, dry and/or flaky skin and to soothe red, and/or irritated skin. Consumers also desire cosmetic products which treat spots, pimples, blemishes etc.

Green tea polyphenols, retinoids and fatty acids are known skin care benefit agents which are known to deliver skin condition and anti-aging benefits to skin, and hence are desirable active components in skin treatment regimes. However, several of these molecules are unstable in cosmetic formulations. In particular, green tea polyphenols are known to oxidise readily, causing an undesirable 'browning' of the formulation. Other agents such as retinoids (especially retinol) and fatty acids such as long chain (C15 to C22) conjugated fatty acids are also prone to oxidation, rendering them less effective.

Several methods including encapsulation, enzymatic modification of molecules, and antioxidants such as vitamin E have been used to stabilize or protect molecules prone to oxidation in cosmetic formulations. However, the prior art attempts have been deficient in the prevention of oxidation of many cosmetic benefit agents, especially materials such as green tea polyphenols.

In another technical area, it is known that certain oxygenase enzymes, and in particular dioxygenase enzymes such as quercetinase (also known as quercetin 2,3-dioxygenase) and catechinase may be suitable for deoxygenating food products, and thereby preventing their degradation. For example, in co-pending application PCT/EPOO/04422, there is described the deoxygenation of foodstuff materials by the incorporation of a dioxygenase enzyme such as quercetinase or catechinase, preferably together with a substrate material (which is typically an antioxidant). The dioxygenase enzyme, in particular when in combination with the substrate material, is said to be particularly beneficial in preventing degradation of materials such as unsaturated fatty acids and triglyceride oils.

In another technical field, W099/ 16472 describes the use of oxygen scavenging enzymes such as glucose oxidase, galactose oxidase and lactoperoxidase in cosmetics. However, such enzymes in use generate hydrogen peroxide, which is undesirable since it generates free radicals in the skin, which can not only promote aging, but may act to destabilize the cosmetic formulation. We have now surprisingly found further undisclosed uses of certain oxygenase enzymes, especially those which do not generate hydrogen peroxide or radicals on the skin, and in particular dioxygenases such as quercetinase and catechinase, as well as monooxygenases which act in a surprisingly efficacious manner to prevent the oxidation of oxygen sensitive skin benefit agent species such as green tea polyphenols, retinoids, vitamin C and certain fatty acids in cosmetic compositions for topical application to skin, and to provide previously undisclosed skin care benefits.

In particular, we have now found that improved treatment and prevention of normal skin conditions due to chronoaging or photoaging, such as wrinkles, lines, sagging, hyperpigmentation and age spots, may be obtained through the application of cosmetic compositions to the skin which contain a known skin care benefit agent material such as a green tea polyphenol, a retinoid, vitamin C or a fatty acid, in combination with an oxygenase enzyme which does not generate hydrogen peroxide or radicals in the skin, and in particular a dioxygenase enzyme such as quercitinase and catechinase. This combination of materials has been found to provide a topical composition which has su risingly good stability, and hence may provide not only an improved efficacy for a relatively long period of time, but also any discolouration of the product caused by oxidation of the skin care benefit agent is prevented.

Thus, in a first aspect the invention comprises a topical composition for application to the human skin comprising an effective amount of an oxygenase enzyme which does not generate hydrogen peroxide or radicals in the skin, in particular a dioxygenase enzyme, in combination with a skin care benefit agent, which is preferably a green tea polyphenol, a retinoid, vitamin C or a fatty acid, or mixture thereof, and a cosmetically acceptable vehicle. According to a further aspect of the present invention there is a method of providing at least one cosmetic skin care benefit selected from: treating/preventing wrinkling, sagging, aged and/or photodamaged skin; boosting collagen deposition in skin, boosting decorin production in skin; soothing irritated, red and/or sensitive skin; improving skin texture, smoothness and/or firmness; the method comprising applying to the skin a topical composition comprising an oxygenase enzyme which does not generate hydrogen peroxide or radicals in the skin, in particular a dioxygenase, in combination with a skin care benefit agent, especially a green tea polyphenol, a retinoid, vitamin C or a fatty acid.

The present invention also encompasses the use of oxygenase enzymes which do not generate hydrogen peroxide or radicals in the skin such as dioxygenases in combination with a skin care benefit agent such as a green tea polyphenol, a retinoid, vitamin C or a fatty acid in a topical composition for providing at least one improved skin care benefit selected from treating/preventing wrinkling, sagging, aged and/or photodamaged skin; boosting collagen deposition in skin, boosting decorin production in skin; soothing irritated, red and/or sensitive skin; enhanced skin texture, smoothness and/or firmness.

The inventive methods and the use of the certain oxygenase enzymes with skin care benefit agents thus provides inter alia improved anti-aging benefits which result in the promotion of smooth and supple skin with improved elasticity, and a reduced or delayed appearance of wrinkles and aged skin, with improved stability of the topical composition, and in particular reduced discolouration. A general improvement in the appearance, texture and condition, in particular with respect to the radiance, clarity, and general youthful appearance of skin may be achieved. The inventive methods and uses are also beneficial for soothing and calming sensitive and/or irritated skin. Thus the inventive methods advantageously provide a wide range of skin care benefits.

These benefits might include improved hydration, texture/tone, smoothness, silkiness, firmness, strength/resilience and radiance.

The term "treating" as used herein includes within its scope reducing, delaying and/or preventing the above mentioned skin conditions such as wrinkled, aged, photodamaged, and/or irritated skin and generally enhancing the quality of skin and improving its appearance and texture by preventing or reducing wrinkling and increasing flexibility, firmness, smoothness, suppleness and elasticity of the skin. The cosmetic methods and the uses of the combination of oxygenases and skin care benefit agents according to the invention may be useful for treating skin which is already in a wrinkled, aged, photo-damaged and irritated condition or for treating youthful skin to prevent or reduce those aforementioned deteriorative changes due to the normal aging/photoaging process.

The first essential component of compositions according to the invention are oxygenase enzymes which do not generate hydrogen peroxide or radicals in the skin. Preferred oygenase enzymes are dioxygenase enzymes, although monoxygenase enzymes may also be used.

Oxygenases are enzymes that facilitate the incorporation of one (monooxygenases) or two (dioxygenases) oxygen atoms into organic substrates. In monooxygenases, the non-incorporated oxygen atom is reduced to water either by an additional two electron reductant in the case of external monooxygenases, or by a substrate in internal monooxygenases. With dioxygenases either both oxygen atoms are incorporated into a substrate or one oxygen atom is incorporated into a substrate and the second into an additional co-factor (Chem. Rev. Nov. 1996, vol. 96, No. 7, pages 2275-76). Dioxygenases may comprise copper or iron in their active site. Copper containing dioxygenases are preferred for the method according to the invention.

Preferred enzymes are quercetinase (i.e. an enzyme capable of oxidation of molecules with a quercetin type structure), and catechinase (i.e. an enzyme capable of oxidation of molecules with a catechin type structure). Also suitable are other enzymes such as catechol dioxygenase, and protocatechuate dioxygenase.

According to another embodiment, a mixture of two or more different dioxygenases is used. A mixture of quercetinase and catechinase is a suitable example. Also, a combination of a monooxygenase and a dioxygenases can be applied.

Suitable enzymes with dioxygenase activity are for example those secreted by microorganisms, such as fungi, yeast and bacteria. Preferably the dioxygenase is a fungal dioxygenase of extracellular origin.

A secreted dioxygenase can be obtained from fermentation of a microorganism under any suitable condition, such as fermentation in a rich or minimal culture medium, via induction of the micro-organism via certain organic molecules or building blocks of those molecules, by application of stress conditions during fermentation, or combinations of these measures.

The dioxygenase may be of 'natural origin", or can be one that is produced by a method comprising genetic modification of a micro-organism such as a fungus, under circumstances such that over expression of the desired dioxygenase is achieved. Common, well known genetic modification techniques can be applied. Quercetinase is for example obtainable from Aspergillus japonicus, Aspergillus flavus, Dipothe eres, Neuspora crassa, Diplodia gossypin, Penicillium minioluteum, Penicillium rocforteii, Aspergillus awamori, Aspergillus niger, Aspergillus foetidus, Aspergillus soyae and Aspergillus oryzae.

Catechinase can for example be obtained from Aspergillus japonicus, Neurospora crassa, Diplodia gossypin, Diaporthe eres and Trichoderma reesei.

It is advantageous that both quercetinase and catechinase can be over-expressed in Aspergillus awamori. This mould is a well-known host for production of heterologous proteins and subsequent secretion of these proteins.

The active oxygenases to be employed in accordance with the present invention are present in the topical composition in an effective amount. Normally the total amount of the active is present in an amount between 0.00001% and 1% by weight of the composition. More preferably the amount is from 0.0001% to 0.1% in order to maximize benefits at a minimum cost.

It is believed to be within the capabilities of the skilled person to determine the amount of enzyme that is required to obtain effective oxygen removal. The phrase "effective amount of enzyme" or "stabilising amount of enzyme" is used to indicate that the amount of enzyme in the cosmetic product should be such that oxygen is at least partly removed. Oxygen removal is considered effective when a reduced or no off colour or reduced activity due to oxidised skin care benefit agents is present upon storage. Preferably the amount of enzyme added is in the range of from 5 to 50,000 units of dioxygenase activity per kilogram of cosmetic product, more preferably from 10 to 5,000 units per kilogram of cosmetic product, even more preferably from 10 to 2,000 units per kilogram of cosmetic product, even more preferably from 20 to 1,000 units per kilogram of cosmetic product, most preferably from 50 to 500 units per kilogram of cosmetic product; whereby a unit is defined as the amount of enzyme required to convert 1 μmol of substrate within 1 minute, where applicable.

The skin care benefit agent used in compositions according to the invention is preferably a green tea polyphenol, a retinoid, vitamin C or a fatty acid, which benefit agent is preferably present at a level of 0.0001 to 10%, preferably 0.01 to 5%, more preferably 0.1 to 2% by weight of the composition.

By "retinoids" herein we include retinol, retinoic acids, and retinol and retinoic acids esters.

By "fatty acids" herein we include C15 to C22 saturated and unsaturated, branched and unbranched free fatty acids. Preferred free fatty acids include C18 and C20 unsaturated fatty acids having at least 2 double bonds. Preferably, the term "fatty acids" does not include odiferous esterified fish oil fatty acids.

The invention relates to a method of deoxygenating a cosmetic product. This implies that the cosmetic product is at least partly deoxygenated by the method of the invention. Preferably at least 25 vol%, more preferred at least 50 vol%, most preferred 75 to 100 vol% of oxygen present is removed, compared to cosmetic products of similar composition wherein the enzyme is absent. Oxygen present in the products may be for example dissolved or free, gaseous oxygen. Preferred cosmetic products are storage stable (e.g. do not discolour or show reduced activity) for at least 4 weeks, preferably at least 10 weeks, more preferred around 6 months. This implies that the added enzyme preferably retains its oxygen scavenging activity for at least 4 weeks, more preferred at least 7 weeks, most preferred at least 10 weeks.

It has been found that storage stability can be assured if the enzyme retains at least 25%, preferably at least 50 % of it's activity after 4 weeks, more preferred after 7 weeks. Most preferably the enzyme activity after 7 weeks is 80-100 % of the original activity that was added to the product in the form of a certain amount of enzyme.

The composition used according to the invention also comprises a dermatologically/ cosmetically acceptable vehicle to act as a dilutant, dispersant or carrier for the skin benefit active. The vehicle may comprise materials commonly employed in skin care products such as water, liquid or solid emollients, silicone oils, emulsifiers, solvents, humectants, thickeners, powders, propellants and the like. Highly advantageously, the composition contains an antioxidant which may act as a stabilizer such as α-tocopherol.

The vehicle will usually form from 5% to 99.9%, preferably from 25% to 80% by weight of the composition, and can, in the absence of other cosmetic adjuncts, form the balance of the composition.

Besides the skin care benefit agent and the enzymes, other specific skin-benefit actives such as sunscreens, skin lightening agents and skin tanning agents may also be included. The vehicle may also further include adjuncts, such as perfumes, opacifiers, preservatives, colourants and buffers. To prepare the topical composition used in the method of the present invention, usual techniques for preparing skin care products may be employed. The active components are generally incorporated in a dermatologically acceptable carrier in conventional manner. The active components can suitably first be dissolved or dispersed in a portion of the water or another solvent or liquid to be incorporated in the composition. The preferred compositions are oil-in- water, water-in-oil or water- in-oil-in- water emulsions.

The composition may be in the form of conventional skin-care products such as a cream, gel or lotion or the like. The composition can also be in the form of a so- called "wash-off product e.g. a bath or shower gel, possibly containing a delivery system for the actives to promote adherence to the skin during rinsing. Most preferably the product is a "leave-on" product; that is a product to be applied to the skin without a deliberate rinsing step soon after its application to the skin.

The composition may packaged in any suitable manner such as in ajar, a bottle, tube, roll-ball, or the like, in the conventional manner.

The method of the present invention may be carried out one or more times daily to the skin which requires treatment. The improvement in skin appearance will usually become visible after 1 to 3 months, depending on skin condition, the concentration of the active components used in the inventive method, the amount of composition used and the frequency with which it is applied. In general, a small quantity of the composition, for example from 0.1 to 5 ml is applied to the skin from a suitable container or applicator and spread over and/or rubbed into the skin using the hands or fingers or a suitable device. A rinsing step may optionally follow depending on whether the composition is formulated as a "leave-on" or a "rinse-off product. In order that the present invention may be more readily understood, the following examples are given by way of illustration only.

EXAMPLES

Examples 1-6

The first example demonstrates the reduction of browning in a skin formulation by the dioxygenases catechinase and quercetinase

Methods

Two basic water in oil emulsions were prepared:

Water in Oil emulsion (low level silicone emulsifier)

GTP is green tea polyphenol extract.

The procedure for making Examples 1-3 was as follows.

The oil phase ingredients were mixed together whilst heating to 40/50°C to solubilise the butyl paraben. The water phase ingredients were mixed together whilst heating to 40/50°C to solubilise the methyl paraben. Both phases were left to cool to room temperature. Then the water phase was slowly added to the oil phase under high agitation, whilst stirring intensively for 10 minutes. The mix was homogenised with a Silverson mixer until an even emulsion was obtained. At this point green tea polyphenol extract and catechinase were added to the relevant examples.

Water in Oil cream with high internal phase

The procedure for making examples 4 to 6 (500 grams) was as follows. The oil and water phases were individually prepared, and heated to 75/80°C. The water phase was then slowly added to the oil phase whilst stirring intensively for 15 minutes. The emulsion was left to cool to room temperature. At this point green tea polyphenol extract and the quercetinase were added to the relevant examples (quercetinase at a concentration of 2 mg/ml).

After manufacture of Examples 1-6, aliquots of each Example were stored in vials at 4°C, room temperature (i.e. 23°C) and 45°C. The colour of each formulation was measured, and measurements were then carried out at intervals over a period of several weeks. A calorimeter was used in order to quantify the colour change. The "L value" represents the whiteness which was measured. For each cream, 3 measurements were made for each time point and the mean value calculated.

Table 1. Effect of catechinase on the browning of a skin care formulation containing green tea polyphenols.

These samples were those incubated at room temperature.

The L value measured by the chronometer was an indication of how white the colour of the formulation was, with the lower the L value, the darker the colour. The colour of the formulation containing the green tea polyphenols without catechinase (E.g.2) changed to a beige colour with a decrease of approximately 1.0 L value unit over the 10 day test period. This browning effect was due to the oxidation of the green tea polyphenol in the formulation. The addition of the dioxygenase catechinase (E.g. 3) reduced the browning effect of the green tea polyphenols by approximately 0.7 of a L value unit. Hence, the addition of catechinase to the formulation reduced the browning of the formulation by green tea polyphenols, and thus the oxidation of this skin care active.

Table 2. Effect of quercetinase on the browning of a skin car formulation containing green tea polyphenols

These samples were incubated at room temperature.

In example 6 the colour of the formulation containing the green tea polyphenols changed to a beige colour with a decrease of 0.8 of a L value unit over the 7 day test period. This browning effect was due to the oxidation of the green tea polyphenol in the formulation. The addition of the dioxygenase quercetinase reduced the browning effect of the green tea polyphenols by approximately 0.5 of a L value unit. Hence, the addition of quercetinase to the formulation reduced the browning of the formulation by green tea polyphenols, and thus the oxidation of this skin care active.

The data here demonstrates that the addition of the dioxygenases catechinase and/or quercetinase to skin compositions reduced the oxidation of green tea polyphenols in skin composition. Such compositions give greater skin benefit than those green tea polyphenols compositions without dioxygenase, as well as having reduced discolouration.

Example 7

The formulation below describes an oil in water cream suitable for the methods and uses according to the present invention. The percentages indicated are by weight of the composition.

*Brij 56 is cetyl alcohol POE (10)

Alfol 16RD is cetyl alcohol

Example 8

The formulation below describes an emulsion cream formulation according to the present invention.

Both the above topical compositions of examples 7 and 8 may provide an effective cosmetic treatment to improve the appearance of wrinkled, aged, photodamaged, and/or irritated skin, when applied to skin that has deteriorated through the ageing or photoageing or when applied to youthful skin to help prevent or delay such deteriorative changes. The compositions can be processed in conventional manner.

Claims

1. A topical composition comprising:

(a) an effective amount of an oxygenase enzyme which does not generate hydrogen peroxide or radicals in the skin;

(b) a skin care benefit agent; and

(c) a dermatologically acceptable vehicle.

2. A topical composition according to Claim 1 wherein the oxygenase enzyme is a dioxygenase enzyme.

3. A topical composition according to Claim 2 wherein the dioxygenase enzyme is catechinase or quercetinase.

4. A topical composition according to any of the preceding claims, wherein the oxygenase enzyme is present at a level of 0.00001 to 1% by weight of the composition.

5. A topical composition according to any of the preceding claims, wherein the skin care benefit agent is a green tea polyphenol, a retinoid, vitamin C or a fatty acid.

6. A topical composition according to Claim 5, wherein the skin care benefit agent is a green tea polyphenol.

7. A topical composition according to Claim 5 or Claim 6, wherein the skin care benefit agent is present at a level of 0.0001 to 5% by weight of the topical composition.

8. A cosmetic method of providing at least one cosmetic skin care benefit selected from: treating/preventing wrinkling, sagging, dry, aged and/or photodamaged skin; improving skin texture, smoothness and/or firmness; and soothing irritated, red and/or sensitive skin; the method comprising applying to the skin a topical composition as claimed in any of Claims 1 to 7.

9. Use of a topical composition as claimed in any of Claims 1 to 7 for providing at least one skin care benefit selected from treating/preventing wrinkling, sagging, aged, dry, and/or photodamaged skin; soothing irritated, red and/or sensitive skin; improving skin texture, and smoothness and/or firmness.