Protection by multiple antioxidants against lipid peroxidation in rat liver homogenate

The purpose of this study was to test the hypothesis that multiple antioxygenic nutrients provide increased protection against lipid peroxidative damage to rat liver. Rats were fed diets (i) deficient in vitamin E and selenium (Diet 1), (ii) supplemented with vitamin E and selenium (Diet 2), (iii) supplemented with (ii) and in addition trolox C, N-acetylcysteine, coenzyme Q0, and (+)-catechin (Diet 3), or (iv) supplemented with (iii) and in addition beta-carotene, ascorbic acid palmitate, canthaxanthin, and coenzyme Q10 (Diet 4). Liver homogenates were obtained from three rats fed each of the diets for six weeks and were incubated at 37 degrees C up to two hours with and without exogenous tertiary-butyl hydroperoxide (TBHP) or Cu2+. Lipid peroxidation was determined by measurement of thiobarbituric acid substances. Diets 2 and 3 significantly protected against in vivo hepatic lipid peroxidation, and this protection was augmented by Diet 4. Diets 2, 3, and 4 were protective against mild oxidation induced by TBHP or Cu2+. During incubations with exogenous TBHP and Cu2+, there were only small differences between diets supplemented with antioxidants in inhibition of lipid peroxidation, indicating that diets supplemented with vitamin E and selenium (Diet 2) may have provided the maximal protection for liver. The possible mechanisms of protection provided by multiple antioxidants in diets were discussed. Protection by multiple antioxidants against lipid peroxidation may translate to prevention of peroxidative damage to human tissue, a factor in human disease.