From the 2003 FDA Science Forum
W.G.Wamer1, P.Vath2, D.E.Falvey2, 1University of Maryland
Various retinoids, including retinol, retinyl acetate and retinyl palmitate, are added to cosmetics that are applied to sun-exposed areas of the skin. It is well established that these retinoids absorb ultraviolet light and undergo a variety of photochemical reactions. The phototoxicological consequences of these photochemical transformations are less well understood. We have determined that incubation of human skin fibroblasts with 20 uM retinol or retinyl acetate, followed by irradiation with UVA light (320 nm to 400 nm), results in significant photocytotoxicity, measured as inhibition of cellular growth. Additional photochemical studies, using laser flash photolysis methods, suggest that the observed photocytotoxicity involves the retinyl cation, formed following absorption of UV light by retinyl acetate or retinol. We are currently conducting studies to determine the cellular targets damaged by photo-activated retinol and retinyl acetate.