Antioxidant effects of the combination of conjugated linoleic acid and phytosterol supplementation in Sprague–Dawley rats

Abstract

The aim of this study was to investigate the effects of dietary conjugated linoleic acid (CLA) and phytosterol supplementation and their combination on antioxidant enzyme activities and biomarkers of lipid peroxidation in healthy rats. Forty male Sprague–Dawley rats were divided into five groups and received diets supplemented with 2% of soybean oil (group S), safflower oil (group LA) (control), a mixture of c9,t11 and t10,c12 CLA (group CLA), phytosterols (group P) and a mixture of CLA and phytosterols (group CLA+P) for 9weeks. Plasma and hepatic indicators of lipid autoxidation and plasma antioxidant enzymes activities were determined. The supplementation with the mixture of CLA and phytosterols (CLA+P) did not alter food intake, weight gain, plasma malondialdehyde (MDA) and glutathione (GSH) values, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRd) activities (P>0.05). The supplementation with CLA significantly increased plasma catalase (CAT) activity (3.7-fold) and plasma 8-isoprostane values (60%) compared to S group (P<0.05). However, the association between CLA and phytosterols was able to restore the CAT and 8-isoprostane levels to basal values, since these indicators in the CLA+P group were statistically similar to S group. CLA+P supplementation also decreased lipid peroxidation primary (58%) and secondary (52%) products in liver (P<0.05). Supplementation of isolated phytosterols and CLA was also able to reduce hepatic lipid peroxidation products and plasma levels of MDA (P<0.05). The dietary combination of CLA+P improved the antioxidant status, reduced the lipid peroxidation and protected against possible effects of CLA supplementation on oxidative stress in vivo.