Scavenger effect of vitamin E and derivatives on free radicals generated by photoirradiated pheomelanin.
The free radical scavenger properties of vitamin E (DL-alpha-tocopherol), a natural antioxidant, and derivatives were studied using an original in vitro method consisting of free radical production by photoirradiation of pheomelanin and direct detection of the free radicals by a physical, specific technique, electron spin resonance. Validation of this method has been realized using well-known biological free radical scavengers, superoxide dismutase and reduced glutathione. DL-alpha-Tocopherol, tocopheryl acetate, tocopheryl linoleate, and tocopheryl polyoxyethylene (POE) succinate induced a significant diminution of the free radical production. In order of efficiency, tocopheryl POE succinate was the best scavenger (37.6% inhibition at 0.25%) followed by tocopheryl linoleate (25.6% inhibition at 1%) and tocopheryl acetate (23.9% inhibition at 0.5%) and finally DL-alpha-tocopherol (16.2% inhibition at 0.05%). The results reported a decrease of the inhibitory effect for high concentrations of DL-alpha-tocopherol (0.1%) and tocopheryl acetate (1%), showing a tendency of this compound to act as a prooxidant. Used in optimal concentrations in cosmetologic or dermatologic formulations, Vitamin E and these derivatives should prevent or reduce the harmful activity of free radicals in the skin.
Duval
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C
Département Dermopharmacie et Biophysique Cutanée, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France.
Poelman
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MC
D000818:Animals; D002417:Cattle; D016166:Free Radical Scavengers; D005609:Free Radicals / Q000737:chemistry; D008543:Melanins / Q000737:chemistry* / Q000528:radiation effects; D017785:Photons; D013482:Superoxide Dismutase / Q000097:blood; D014810:Vitamin E / Q000031:analogs & derivatives / Q000494:pharmacology*
D016166:Free Radical Scavengers; D005609:Free Radicals; D008543:Melanins; C018362:pheomelanin; D014810:Vitamin E; D013482:Superoxide Dismutase