TOPICAL MELATONIN IN COMBINATION WITH VITAMIN-E AND VITAMIN-C PROTECTS SKIN FROM ULTRAVIOLET-INDUCED ERYTHEMA - A HUMAN STUDY IN-VIVO

In this randomized, double-blind human study, the short-term photoprot ective effects of different antioxidants and their combinations were e valuated in vivo. Vitamin C (ascorbic acid), vitamin E (alpha-tocopher ol) and melatonin (N-acetyl-5-methoxytryptamine) were topically applie d, alone or in combination, 30 min before ultraviolet-irradiation of t he skin. The erythemal reaction was evaluated visually and non-invasiv ely using different bioengineering methods (skin colour and skin blood now). The results showed a modest protective effect of the vitamins w hen applied alone and a dose-dependent photoprotective effect of melat onin. Topical application of combinations of both vitamins, or of mela tonin with vitamins, enhanced the photoprotective response. Better pro tection was obtained by using the combination of melatonin with both v itamins. The role of reactive oxygen species and oxygen-derived free r adicals, as well as potential sunscreening properties of the employed antioxidants, are discussed in view of possible mechanisms to explain this elevated photoprotective effect.