We present an in vivo test platform to evaluate the antioxidative capability of seven frequently used
dermocosmetic antioxidants on the human stratum corneum (SC). It has been reported that the protein
carbonylation could be used as a biomarker for oxidative stress. The current study detects the change of
the level of exposed protein carbonyl group in the most outer layer of human SC. The concentration of the
antioxidant in each subject emulsion formulation was 0.5% (w/w). The data indicated that alpha-tocopherol
(a-Vit E) and ascorbic acid (Vit C) have excellent antioxidative capability and a-Vit E-acetate possesses
better than the average antioxidative capability. The bioconversion of a-Vit E-acetate to a-Vit E
may occur in the human SC during a less than 2 weeks time course test. Lipoic acid possessed moderate
antioxidative capability. Ascorbyl 6-palmitate had a low antioxidative capability. Ascorbic acid 2-glucoside
represented an insignificant antioxidative capability. Glutathion (GSH) had no effect on reducing oxidative
damage to human SC proteins, implying that the GSH recycling system could be absent in human
SC. This test platform is an useful tool to evaluate the antioxidative efficiency of antioxidants on human
SC proteins.
