Studies on Cosmetical Efficiency of Trace Metals (I): The Effect of Metals on Glutathione Peroxidase

The importance of metal ions in biological functions has been studied mainly in the field of medicine. We have been interested in the effects of metal ions in the field of cosmetics and tried to investigate what significant roles they play in vivo, especially in the regulation of enzymes. Glutathione peroxidase (GSHpx) was chosen from among the enzymes which remove the free radicals closely related to skin aging. GSHpx has two activities, (1) It decomposes lipid peroxides into lipids and water, (2) It decomposes hydrogen peroxide into water. We studied the effect of adding metal ions to see whether the enzyme repressed the formation of lipid peroxides by exposure to light and decomposed any lipid peroxides formed. Our results showed that with the addition of copper or selenium the ability of GSHpx to decompose lipid peroxides and hydrogen peroxides increased considerably but its ability to repress the formation of lipid peroxides was not observed. These effects of GSHpx are opposite to those of vitamin E which is used for the prevention of lipid peroxides formation. Therefore, this complementary relationship between Vitamin E and GSHpx gives us much useful information for cosmetic science.