Resveratrate protects human skin from damage due to repetitive ultraviolet irradiation.

BACKGROUND: Ultraviolet (UV) exposure results in the production reactive oxygen species. Resveratrol has attracted considerable attentions owing to its natural abundance and multiple biological effects. OBJECTIVE: To investigate the protective effects of resveratrate against damage to human skin induced by repetitive solar simulator ultraviolet radiation (ssUVR). MATERIALS AND METHODS: Fifteen healthy volunteers were enrolled, and six sites on the non-exposed dorsal skin of each volunteer were marked for study. Sites 1-4 were exposed to ssUVR at a dosage of 1.5 minimal erythema dose for consecutive 4 days. Immediately after each exposure, one test material (resveratrate + antioxidant, antioxidant, resveratrate, vehicle) was applied to one of the four sites. Site 5 and site 6 were marked as positive control site (UVR only) and baseline control site (no treatment, no UVR). L*a*b values were assessed preprocedure and postprocedure. Skin biopsies were taken 24 h after the last irradiation. The specimens were stained to determine the number of sunburn cells and melanin content melanin. RESULTS: On resveratrate treated sites, erythema was barely seen with only slight decrease of L value and insignificant increase of *a value. Furthermore, resveratrate significantly inhibited sunburn cell formation, and decreased Fontana-Masson staining in skin samples. CONCLUSIONS: Resveratrate exerts protective effects against repetitive ssUVR-induced sunburn and suntan.