2005 年 51 巻 1 号 p. 8-15
The antioxidative effect of conjugated linoleic acid (CLA) was examined by determining lipid peroxidation and antioxidative enzyme activities. Male Sprague-Dawley rats were fed one of the experimental diets-normal diet, vitamin E-deficient control diet, 0.5% CLA vitamin E-deficient diet, or 1.5% CLA vitamin E-deficient diet for 5wk. Hepatic thiobarbituric acid reactive substances (TSARS) were increased in the vitamin E-deficient control group, but they were was significantly lowered in the CLA groups. Similarly, hepatic glutathione peroxidase activity was increased in the vitamin E-deficient diet and reduced by CLA supplementation. In addition, CLA caused a significant decrease in superoxide dismu-tase activity while having no effect on catalase activity. Analyses of the fatty acid composi-tion revealed that dietary CLA was incorporated into hepatic microsomal membrane dose-dependently. Compared to the vitamin E-deficient control, CLA resulted in significantly higher saturated and monounsaturated fatty acids (palmitic and oleic acids) while lowering levels of oxidation-susceptible polyunsaturated fatty acids (linoleic, linolenic, and arachi-donic acids) in both plasma and hepatic membrane. The concentrations of plasma choles-terol and triacylglycerol (TG) were lower in the 1.5% CLA group than in other groups. These results suggest that dietary CLA has antiatherosclerotic and antioxidant activity by increas-ing oxidative stability in plasma and hepatic membrane in the vitamin E-deficient rats.
