Antioxidative cosmetic additives for the protection of human skin surface lipids against environmental stress

Abstract

Studies were carried out in vitro to investigate the effect of a simulated polluted atmosphere containing ozone, sulfur dioxide, and nitrogen dioxide on human skin surface lipids and to evaluate the potency of antioxidative cosmetic additives for the protection against detrimental oxidation processes caused by air polluting substances. The experiments showed that the air pollutants caused significantly increased oxidation effects on human skin surface lipids compared to non polluted atmosphere as indicated by the increase of the peroxide values. The addition of selected derivatives of ascorbic acid, tocopherol, or retinol as specific cosmetic additives with particular antioxidative activity both as pure substances and as ingredients of cosmetic skin care formulations resulted in a considerable protection against oxidative effects of the air pollutants on human skin surface lipids, in which the antioxidative complex tocopherol/hydrogenated tallow glyceride citrate is most effective. Even by additional irradiation with artificial erythemogenic sunlight during the exposure to the air polluting substances of a skin care formulation composed of tocopherol/hydrogenated tallow glycerides as antioxidative component and zinc oxide as UV‐filter substance, the significant lipid‐protective efficacy of the antioxidative cosmetic additive was only slightly diminished.