JPH0567125B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a whitening cosmetic that eliminates or prevents skin darkening or skin pigmentation such as spots and freckles caused by ultraviolet rays by incorporating a specific fatty acid or its derivative into a cosmetic base. BACKGROUND ART AND PROBLEMS Conventionally, whitening cosmetic compositions containing vitamin C and derivatives thereof, reducing agents, and tyrosinase activity inhibitors such as placenta extract are known. However, although these conventional whitening cosmetics have shown suppressive effects on melanin production in in vitro experiments using cultured cells, when applied to the skin in experiments, they have not been able to sufficiently eliminate or prevent pigmentation. An object of the present invention is to provide a cosmetic that exhibits excellent whitening effects without side effects when actually applied to the skin. Means for Solving the Problems As a result of intensive research to achieve the above object, the present inventors have found that specific fatty acids and their derivatives have an excellent effect on eliminating or preventing skin pigmentation. This discovery led to the completion of the present invention. That is, the present invention provides a whitening cosmetic containing as an active ingredient a free fatty acid having 18 to 22 carbon atoms and 2 or more unsaturations in its molecular structure, a salt thereof, or an ester with a monohydric or dihydric alcohol. It is something. The fatty acids having 18 to 22 carbon atoms and having 2 or more unsaturations in the molecular structure, such as linoleic acid and γ-linolenic acid, which are blended into the composition of the present invention, are contained in vegetable oils and animal fats. . However, these fatty acids rarely exist in a free state, and most of them exist in the form of triglycerides. Such triglycerides, unlike free fatty acids or their alkyl esters, have not been found to have an excellent pigmentation suppressing effect in animal tests. Similarly, saturated fatty acids such as palmitic acid and stearic acid do not have the same pigmentation-suppressing effect, and in some cases may even promote melanin production. Since such saturated fatty acids are contained in large quantities in vegetable oils and animal fats, it is preferable to use purified fatty acids when blending linoleic acid and the like in the cosmetic composition of the present invention. Carbon number 18-22 blended into the whitening cosmetic of the present invention
Typical free fatty acids with two or more unsaturations in their molecular structure include linoleic acid, linoleaidic acid, α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, Examples include icosapentaenoic acid, and one or more of these may be used. Examples of the salts of these free fatty acids include metal salts such as sodium salts and potassium salts, amino acid salts such as arginine salts and lysine salts, and amine salts such as triethanolamine salts and monoethanolamine salts. Furthermore, the alkyl esters of free fatty acids include esters with monohydric alcohols such as methanol, ethanol, and isopropyl alcohol;
ethylene glycol, propylene glycol,
Examples include esters with dihydric alcohols such as 1,3-butylene glycol. The content of these free fatty acids, salts, or esters in cosmetics is preferably 0.1 to 10% by weight. If the amount is less than 0.1% by weight, there will be no effect of suppressing pigmentation, while if it exceeds 10% by weight, it will be highly irritating. Next, the results of evaluating the pigmentation suppressing effects of various active ingredients are shown. Test method: The backs of English brown guinea pigs were shaved and irradiated with ultraviolet light (UVB intensity: 1 J/cm ² ). This operation is repeated for 3 days, during which time fatty acids such as linoleic acid or other ingredients are added to the
(w/v)% of the specimen dissolved in ethanol was applied to the UV irradiated site. After being left for 10 days, the degree of pigmentation was visually judged according to the criteria shown below. Criteria: − No pigmentation ± slight pigmentation + moderate pigmentation ++ strong pigmentation The results are shown in Table 1 below.

[Table] As is clear from Table 1, when a free fatty acid with 18 to 22 carbon atoms and 2 or more unsaturations in the molecular structure, its salt, or alkyl ester is blended, an inhibitory effect on pigmentation is observed. However, saturated fatty acids have no such effect even if they have similar carbon numbers. The whitening cosmetic of the present invention is manufactured in the form of lotion, cosmetic oil, cream, emulsion, pack, powder, etc. by a known method. Further, the cosmetic composition of the present invention may contain any known ingredients as appropriate, depending on the type thereof, within a range that does not impair performance. In addition, conventionally used melanin production inhibitors (vitamin C, placenta extract), ultraviolet absorbers,
Ultraviolet scattering agents, anti-inflammatory agents, antioxidants, etc. may be added. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Example 1 (Cosmetic) Component Amount (wt%) Linoleic acid 0.5 Glycerin 6.0 Ethanol 8.0 Polyoxyethylene hydrogenated castor oil 0.8 Methyl paraoxybenzoate 0.05 Citric acid 0.05 Sodium citrate 0.07 Fragrance 0.1 Water-soluble placenta extract 2.0 Purified water Remainder: Dissolve glycerin, citric acid, sodium citrate, and water-soluble placenta extract in purified water. Separately, linoleic acid, polyoxyethylene hydrogenated castor oil (60E.O.), methylparaben, and fragrance were dissolved in ethanol, added to the purified aqueous solution, solubilized, and filtered to obtain a lotion. Example 2 (Cosmetic oil) Ingredients Amount (% by weight) Ethyl linoleate 1.0 Ascorbyl palmitate 0.2 Retinol acetate 0.3 Cholesteryl stearate 1.0 Olive oil 2.0 Squalane Remainder Cosmetic oil is made by uniformly dissolving other ingredients in squalane. Obtained. Example 3 (Cream) Component Amount (% by weight) Component (A) γ-linolenic acid 2.0 Ascorbyl stearate 1.0 d,l-α-tocopherol acetate 0.2 White beeswax 4.0 Setanol 2.0 Stearic acid 1.0 Isopropyl myristate 5.0 Lanolin 2.0 Liquid paraffin 9.0 Self-emulsifying glyceryl monostearate 3.0 Polyoxyethylene sorbitan monostearate (20E.O.) 1.5 Propyl paraoxybenzoate 0.1 Component (B) Methyl parahydroxybenzoate 0.2 Propylene glycol 5.0 Fragrance 0.2 Purified water Balance Component (A) ) is dissolved by heating and kept at 80℃. Separately, component (B) excluding fragrance is dissolved by heating and maintained at 80° C., and the component (A) is added thereto with stirring and mixed thoroughly. The mixture was further cooled while stirring, a fragrance was added, and the mixture was further cooled to obtain a cream. Example 4 (Emulsion) Component Amount (wt%) Component (A) Isopropyl linoleate 2.0 Stearyl glycyrrhetinate 0.1 Liquid paraffin 5.0 Vaseline 2.0 Beeswax 1.0 Sorbitan sesquioleate 2.0 Component (B) Polyoxyethylene 2.5 Oleyl ether (20E) .O.) Ethyl paraoxybenzoate 0.2 Propylene glycol 5.0 Carboxyvinyl polymer 0.5 Potassium hydroxide 0.5 Fragrance 0.2 Purified water Balance Dissolve component (A) by heating at 80℃, and separately heat (80℃)
℃) Add to ingredients (B) excluding the dissolved fragrance while stirring and mix thoroughly. Next, the mixture was cooled while stirring, perfume was added, and the mixture was further cooled to obtain a milky lotion. Example 5 (Pack) Component Amount (wt%) Linoleic acid 3.0 Hydroxy placenta extract 2.0 Vinyl acetate-styrene copolymer 10.0 Polyvinyl alcohol 10.0 Sorbit 5.0 Titanium oxide 8.0 Kaolin 7.0 Ethanol 5.0 Fragrance 2.0 Ethyl paraoxybenzoate 0.2 Purification Water Balance Uniformly dissolve linoleic acid, fragrance, and ethanol. This is converted into vinyl acetate/styrene copolymer,
Add polyvinyl alcohol, sorbitate, titanium oxide and kaolin to a homogeneous mixture.
To this, a solution in which water-soluble placenta extract and ethyl paraoxybenzoate were uniformly dissolved in purified water was added and mixed uniformly to obtain a pack. Example 6 (Powder) Component Amount (wt%) Linoleic acid 2.0 Dextrin 95.0 Talc 2.0 Decaglyceryl stearate 1.0 Linoleic acid and decaglyceryl stearate were dissolved by heating, held at 70°C, and dissolved in dextrin and talc. It was gradually added to the mixture with stirring to obtain a powder. Effect of the invention By applying the cosmetic of the present invention to the skin,
It has an excellent whitening effect by eliminating or preventing skin darkening or pigmentation caused by ultraviolet rays.

Claims (1)

[Claims] 1. 18 to 22 carbon atoms and 2 unsaturations in the molecular structure.
A whitening cosmetic containing the above free fatty acids, their salts, or esters with monohydric or dihydric alcohols as active ingredients. 2 The amount of the active ingredient to be added to the entire composition
The whitening cosmetic according to item 1 above, which contains 0.1 to 10% by weight.