Cosmetic use of salicylic acid derivatives

1. A cosmetic composition comprising, in a cosmetically acceptable vehicle, an effective amount of a salicylic acid derivative having the structure of formula (I):

where R a and R b are independently selected from hydrogen or C 1 -C 12 branched, straight chained or cyclic hydrocarbons, optionally substituted with 1-4 heteroatoms selected from halogen, oxygen, nitrogen, and sulfur;

and cosmetically acceptable salts thereof

wherein said effective amount is between about 0.001% by weight to about 5% by weight based on the total weight of the composition.

2. The cosmetic composition according to claim 1 , wherein R a and R b are independently selected from hydrogen, methyl, ethyl, propyl, butyl, pentyl, and hexyl.

3. The cosmetic composition according to claim 1 , wherein R a and R b are both ethyl.

4. The cosmetic composition according to claim 1 , wherein R a and R b are both hydrogen.

5. The composition according to claim 1 , wherein said cosmetically acceptable vehicle comprises a water-in-oil, oil-in-water, silicone-in-water, or water-in-silicone emulsion and further comprises an emulsifier.

6. The composition according to claim 1 , further comprising a retinoid selected from the group consisting of retinoic acid, retinol, retinal, retinyl acetate, and retinyl palmitate.

7. The cosmetic composition according to claim 1 , further comprising a cosmetic ingredient selected from a film forming polymer, a thickener, a pH adjuster, a preservative, an emulsifier, a gelling agent, an antioxidant, an emollient, a humectant, a fragrance, and a colorant.

8. A method for improving the aesthetic appearance of human skin comprising topically applying to an area of the skin in need thereof a composition according to claim 1 , for a time sufficient to improve the aesthetic appearance of said human skin.

9. The method according to claim 8 , wherein said aesthetic improvement of said human skin is selected from the group consisting of:

(a) treatment, reduction, and/or prevention of fine lines or wrinkles;

(b) reduction of skin pore size;

(c) improvement in skin thickness, plumpness, and/or tautness;

(d) improvement in skin smoothness, suppleness and/or softness;

(e) improvement in skin tone, radiance, and/or clarity;

(f) improvement in procollagen, and/or collagen production;

(g) improvement in maintenance and remodeling of elastin;

(h) improvement in skin texture and/or promotion of retexturization;

(i) improvement in skin barrier repair and/or function;

(j) improvement in appearance of skin contours;

(k) restoration of skin luster and/or brightness;

(l) replenishment of essential nutrients and/or constituents in the skin;

(m) improvement of skin appearance decreased by aging and/or menopause;

(n) improvement in skin moisturization;

(o) increase in skin elasticity and/or resiliency;

(p) treatment, reduction, and/or prevention of skin sagging;

(q) improvement in skin firmness; and

(r) reduction of pigment spots and/or mottled skin; and

(s) improvement of optical properties of skin by light diffraction or reflection.

10. The method according to claim 9 , wherein said composition is applied at least once daily for a period of at least four weeks.

11. A method for reducing blemishes or acne in human skin comprising topically applying to an area of the skin in need thereof a composition according to claim 1 , for a time sufficient to improve the aesthetic appearance of said blemish or acne.

12. A method for promoting exfoliation of human skin comprising topically applying to an area of the skin in need thereof a composition according to claim 1 .

13. A cosmetic composition comprising, in a cosmetically acceptable vehicle, an effective amount of a salicylic acid derivative having the structure:

and cosmetically acceptable salts thereof, wherein said effective amount is from about 0.001% and about 5% by weight.

14. A method of improving the aesthetic appearance of skin comprising topically apply to said skin the composition of claim 13 .

15. The composition according to claim 13 , further comprising a retinoid selected from the group consisting of retinoic acid, retinol, retinal, retinyl acetate, and retinyl palmitate.

16. The composition according to claim 1 , further comprising a retinoid selected from the group consisting of retinoic acid, retinol, retinal, retinyl acetate, and retinyl palmitate.

17. A method of screening for dermatologically active substances comprising contacting KLK5 protease with a peptide substrate for KLK5 protease in the presence of the test substance, wherein said peptide substrate comprises a fluorescent group and a quencher in sufficient proximity such that the fluorescent group does not emit light from the intact substrate, and wherein the KLK5 protease cleaves the substrate to release the fluorescent group to produce a detectable signal, and wherein an increase in fluorescent signal indicates that said test substance stimulates KLK5 activity.