Photoprotective actions of topically applied vitamin E

Topical application of vitamin E has been shown to decrease the incidence o f ultraviolet (UV)-induced skin cancer in mice. Vitamin E provides protecti on against UV-induced skin photodamage through a combination of antioxidant and UV absorptive properties. Topical application of alpha -tocopherol on mouse skin inhibits the formation of cyclobutane pyrimidine photoproducts. However, topically applied alpha -tocopherol is rapidly depleted by UVB rad iation in a dose-dependent manner. The photooxidative fate of the alpha -to copherol depends on the local environment of the vitamin E. alpha -Tocopher ol quinone and alpha -tocopherol quinone epoxides are principal photoproduc ts of vitamin E that has penetrated into the epidermal layer of the skin, w hereas tocopherol dimers and trimers are formed from alpha -tocopherol in a bulk phase at the skin surface. Dimer and trimer products may participate in prevention of UV-induced photodamage.