Antioxidants and the response of skin to oxidative stress: vitamin E as a key indicator

As the outermost barrier of the body, the skin is directly and frequently exposed to a prooxidative environment, including solar UVA and UVB radiation, and air pollution. The skin is equipped with an elaborate system of antioxidant substances and enzymes that includes a network of redox active antioxidants. Among these, vitamin E has been identified as the predominant antioxidant both in murine and human skin and shows a characteristic gradient with lower levels towards the outer stratum corneum layers. Skin exposure to UV and ozone alone and in combination resulted in a significant potentiation of the UV-induced vitamin E depletion. Oxidants and antioxidants play an important role in maintaining a balance between free radicals produced by metabolism or derived from environmental sources. Cellular antioxidants may change their redox state, be targeted for destruction, regulate oxidative process involved in signal transduction, affect gene expression and pathways of cell proliferation and death. Here we provide an overview of the antioxidant system with a special relevance to skin.