Skin-lightening

Details Skin-lightening Skin-lightening

2002-04-11

2003-11-18

Tate, Christopher R. (Department: 1651)

Drug, bio-affecting and body treating compositions

Bleach for live hair or skin

C424S769000, C424S777000

Reexamination Certificate

active

06649150

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to novel skin lightening or whitening or even toning compositions and methods of administering same for their pharmaceutical, cosmetic and aesthetic applications.
BACKGROUND OF THE INVENTION
As stated in the scientific literature, the type and amount of melanin synthesized by the melanocyte and its distribution pattern in the surrounding keratinocytes determines the actual color of the human skin. Melanin forms through a series of oxidative reactions involving the amino acid tyrosine in the presence of the enzyme tyrosinase. The first step is the most critical because the remainder of the reaction sequences can proceed spontaneously at physiological pH. Thus, tyrosinase converts tyrosine to dihydroxyphenylalanine (DOPA) and then to dapaquinone. Subsequently, dopaquinone converted to dopachrome, through autooxidation, and finally to dihydroxyindole or dihydroxyindole-2-carboxylic acid (DHICA) to form eumelanin (brown-black pigment). The later reaction occurs in the presence of dopachrome tautomerase and DHICA oxidase. In the presence of cysteine or glutathione, dopaquinone is converted to cysteinyl DOPA or glutathione DOPA. Subsequently, pheomelanin, a yellow-red pigment, is formed.
The color of the skin and its intensity therefore depend on the rate of formation of the melanin, its degree of polymerization, the speed of exfoliation and the thickness of the horny layer, i.e. the layer that contains the most pigment. For a more detailed discussion of the pigmentation pathway, attention is invited to “Skin Depigmenting Agents”, Michael P. Tabibran M.D., (Medicine Journal, Jul. 8, 2001, Vol. 2, November 7.)
In general, to reduce cutaneous pigmentation, it is necessary to reduce the rate of formation of the melanin by inhibiting the tyrosinase while retarding its polymerization and accelerating the exfoliation of the horny layer.
For purposes of skin lightening or whitening or even toning, topical application of skin lightening or whitening or even toning agent should have a lightening, whitening or even toning effect on the only area to be treated, produce neither irritation nor post-inflammatory secondary pigmentation, and cause neither a systemic depigmenting effect nor an allergic reaction.
In addition, the skin lightening, whitening or even toning should be effective for normal cutaneous pigmentation and its excesses: including but not limited to lentigo senilis, chloasma, hyperpigmentation after use of photosensitizing products, and cicatrical brown spots.
In French patent 2730408 published Aug. 14, 1996, compositions are proposed to regulate cutaneous pigmentation, based on extracts of fruits among which is
Phyllantus emblica
(syn.
Emblica officinalis
). The composition may be based on a dilute-alcoholic extract obtained from the
Phyllantus emblica
or an extract obtained, for example by merely pressing the fruit.
Both the extracts obtained by pressing and the extracts obtained by alcoholic maceration may then be concentrated at a moderate temperature under reduced pressure, preferably less than 50° C., then optionally brought to the dry state by freeze-drying or any other method under reduced pressure and at a temperature that is lower than 50° C. so as to avoid degrading the active ingredients of the fruit. In greater detail, examples 3, 6 and 8 of the French patent 2730408 illustrate the manufacture and uses of extracts based on
Phyllantus emblica.
In this French patent, however, there is no indication of the composition or the chemical nature of the extracts being defined. Conversely, in U.S. Pat. No. 6,124,268, Ghosal, issued Sep. 26, 2000 entitled “Natural Oxidant Compositions, Method For Obtaining Same And Cosmetic, Pharmaceutical and Nutritional Formulations Thereof” there is set forth the chemical composition of extracts of
Emblica officinalis
obtained by extracting the fresh fruit at elevated temperatures; e.g. 70° C., using a very dilute aqueous or alcoholic-water salt solution, e.g. 0.1 to 5%. By this extraction process, in the presence of sodium chloride, for example, hydrolysis of the glycocidic enzymes in the plant is prevented and the product is protected from microbial infestation.
In the Ghosal patent, the antioxidant blend of the constituents is described under the name of “CAPROS”, with claim 8, for example, of the patent setting forth the composition as follows:
An antioxidant blend consisting of, by weight, (1) and (2) about 35-55% of the gallic/ellagic acid derivatives of 2-keto-glucono-&dgr;-lactone; (3) about 4-15% of 2,3-di-O-galloyl-4, 6-(S)-hexahydroxydiphenoylgluconic acid; (4) about 10-20% of 2,3,4,6-bis-(S) -hexahydroxydiphenoyl-D-glucose; (5) about 5-15% of 3′,4′,5,7-tetrahydroxyflavone-3-O-rhamnoglucoside; and (6) about 10-30% of tannoids of gallic/ellagic acid.
The common names of the enumerated compounds are (1) and (2) Emblicanin A and Emblicanin B, (3) Punigluconin, (4) Pedunculagin and (5) Rutin. There is no mention of its utility as a skin lightening or whitening or even toning agent has been indicated by Ghosal.
With respect to acceptability of the products of the French and U.S. Patents for the purposes of skin whitening, they have one or more disadvantages.
An object of the present invention, therefore, is to provide a novel composition and method for whitening or lightening or even toning skin for the above described cosmetic and dermatological indications among others.
Upon further study of this application, other objects and advantages of the invention will become apparent.
SUMMARY
It has been discovered that a closely related but novel standardized antioxidant composition based on an extract of
Emblica officinalis
provides a more acceptable skin whitening composition and method of use.
The antioxidant composition used in the present invention comprises a modification of the CAPROS composition, comprising a standardized extract of low molecular weight (<1000) hydrolyzable tannins, over 40%, preferably 50-80% w/w of Emblicanin A, Emblicanin B, Pedunculagin, and Punigluconin with low levels (<1%, w/w) of total flavonoids whereby the resultant products of the invention can be made into elegant white to off-white formulations. Such a composition is discussed with greater specificity in pages 28-30 of the Aug. 2001 issue of Soap, Perfumery and Cosmetics, the article having the title Ingredients/Emblica, Bearing Fruit, by Ratan K. Chaudhuri. In that article there is no mention, however, of any flavonoids much less the maximum acceptable amounts in the composition.
According to the present invention, the total flavonoids are maintained at a level which does not impair the desired color, e.g. generally, by weight, less than about 1.0%, preferably less than about 0.8%, and even more preferably less than about 0.6%. In comparison, commercial competitive products have significantly higher contents of total flavonoids and exhibit a significantly darker color. Also, the desired concentrations of the Rutin species of flavonoids (3′,4′,5′,7-tetrahydroxyflavone-3-0-rhamnoglucoside) in the standardized extract are less than 1.0%, less than 0.01%, less than 0.001% and less than 0.0001%, with a value of 0.01 to 0.001% being particularly preferred. The most preferred concentrations of the components are on a percent by weight basis of the total dried extract:
Most Preferred Concentrations
Product Identity
% by weight
Emblicanin A
20-35
Emblicanin B
10-20
Pedunculagin
15-30
Punigluconin
 3-12
Total Flavonoids
<1
The standardized composition may exhibit average percentage deviations from these preferred values of:
Product Identity
Preferred Deviation
Most Preferred Deviation
Emblicanin A
±10%
±5%
Emblicanin B
±10%
±5%
Pedunculagin
±10%
±5%
Punigluconin
±10%
±5%
Total Flavonoids
±10%
±5%
The antioxidant composition can be obtained by removal of the total flavonoids by reversed-phase column chromatography or HPLC using a solvent system of acetonitrile, water/phosphoric acid (20/80/1) or

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