Dietary conjugated linoleic acid reduces lipid peroxidation by increasing oxidative stability in rats.
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 5 wk. Hepatic thiobarbituric acid reactive substances (TBARS) 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 dismutase activity while having no effect on catalase activity. Analyses of the fatty acid composition 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 arachidonic acids) in both plasma and hepatic membrane. The concentrations of plasma cholesterol 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 increasing oxidative stability in plasma and hepatic membrane in the vitamin E-deficient rats.
Kim
Hye-Kyeong
HK
Food Function Research Division, Korea Food Research Institute, Seongnam 463-746, Korea.
Kim
Sung-Ran
SR
Ahn
Ji-Yoon
JY
Cho
Il-Jin
IJ
Yoon
Chil-Suk
CS
Ha
Tae-Youl
TY
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001219:Aspartate Aminotransferases / Q000097:blood; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004032:Diet; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis; D005979:Glutathione Peroxidase / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000378:metabolism / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008099:Liver / Q000737:chemistry / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014810:Vitamin E / Q000008:administration & dosage
D000975:Antioxidants; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D044243:Linoleic Acids, Conjugated; D008055:Lipids; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase