Antioxidant properties of Asparagus racemosus against damage induced by γ-radiation in rat liver mitochondria

The possible antioxidant effects of crude extract and a purified aqueous fraction of Asparagus racemosus against membrane damage induced by the free radicals generated during gamma-radiation were examined in rat liver mitochondria. gamma-Radiation, in the dose range of 75-900 Gy, induced lipid pel oxidation as assessed by the formation of thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH). Using an effective dose of 450 Gy, antioxidant effects of A. racemosus extract were studied against oxidative damage in tel-ms of protection against lipid peroxidation, protein oxidation, depletion of protein thiols and the levels of the antioxidant enzyme, superoxide dismutase. An active fraction consisting of polysaccharides (termed as P3) was effective even at a low concentration of 10 mu g/ml. Both the crude extract as well as the P3 fraction significantly inhibited lipid peroxidation and protein oxidation. The antioxidant effect of P3 fraction was more pronounced against lipid peroxidation. as assessed by TEARS formation, while that of the crude extract was more effective in inhibiting protein oxidation. Both the crude extract and P3 fi action also partly protects against radiation-induced loss of protein thiols and inactivation of superoxide dismutase. The inhibitory effects of these active principles, at the concentration of 10 mu g/ml, are comparable to that of the established antioxidants glutathione and ascorbic acid. Hence our results indicate that extracts fi om A. racemosus have potent antioxidant properties in vitro in mitochondrial membranes of rat liver. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.