Photoprotective actions of topically applied vitamin E.
Topical application of vitamin E has been shown to decrease the incidence of ultraviolet (UV)-induced skin cancer in mice. Vitamin E provides protection 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 radiation in a dose-dependent manner. The photooxidative fate of the alpha-tocopherol depends on the local environment of the vitamin E. alpha-Tocopherol quinone and alpha-tocopherol quinone epoxides are principal photoproducts of vitamin E that has penetrated into the epidermal layer of the skin, whereas 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.
Krol
E S
ES
Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson 85721, USA.
Kramer-Stickland
K A
KA
Liebler
D C
DC
D000287:Administration, Topical; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects; D006801:Humans; D008968:Molecular Conformation; D010777:Photochemistry; D011837:Radiation-Protective Agents / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects; D013473:Sunscreening Agents / Q000737:chemistry / Q000494:pharmacology; D014466:Ultraviolet Rays; D014810:Vitamin E / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000528:radiation effects
D000975:Antioxidants; D011837:Radiation-Protective Agents; D013473:Sunscreening Agents; D014810:Vitamin E