Biological and Lipid Antioxidant Activity of Selenium

Because a number of vitamin E deficiency syndromes are responsive to dietary selenium, the possibility of selenium functioning as a lipid antioxidant has been examined. Some very powerful selenium antioxidants are known (Woodbridge, 1959). In the vitamin E-deficient chick, dietary selenite inhibited in vivo and in vitro lipid peroxidation (Zalkin et al., 1960). Further, antioxygenic activity was found for various selenium compounds in simple lipid peroxidation reactions selenoamino acids were weak antioxidants. On the basis of this evidence and the known incorporation of selenium into tissue proteins, Zalkin et al. (1960) suggested that the antioxidants formed in the chick may be selenoamino acids and selenoproteins. Bieri (1961) and Bieri et al. (1961) have reported extensive evidence for inhibition of in vitro lipid peroxidation of liver, kidney, and heart tissue from selenium fed chickens. They also suggested that the lipid antioxidant may be a selenoprotein. Olcott et al. (1961) showed that selenomethionine is a stronger lipid antioxidant than methionine and that selenomethionine decomposes lipid peroxides. 

Inhibition of linoleate peroxidation by high-protein tissue fractions from 

Antioxidant Activity of Protein and Tissue Fractions from Seubnium-Ped 

Sheep kidney Chicken kidney Chicken liver Rat kidney Soluble protein of kidney 

Inhibition of linoleate peroxidation in presence of antioxidant and prooxidant by selenium-tissue fractions. Initial antioxidant addition was 5 X 10 M a-tocopherol. Prooxidant added at 4 hours was 1 X 10 M hemoglobin. 

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