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

The possible antioxidant effects of crude extract and a purified aqueous fr action of Asparagus racemosus against membrane damage induced by the free r adicals generated during gamma-radiation were examined in rat liver mitocho ndria. gamma-Radiation, in the dose range of 75-900 Gy, induced lipid pel o xidation as assessed by the formation of thiobarbituric acid reactive subst ances (TBARS) and lipid hydroperoxides (LOOH). Using an effective dose of 4 50 Gy, antioxidant effects of A. racemosus extract were studied against oxi dative damage in tel-ms of protection against lipid peroxidation, protein o xidation, depletion of protein thiols and the levels of the antioxidant enz yme, superoxide dismutase. An active fraction consisting of polysaccharides (termed as P3) was effective even at a low concentration of 10 mu g/ml. Bo th the crude extract as well as the P3 fraction significantly inhibited lip id peroxidation and protein oxidation. The antioxidant effect of P3 fractio n was more pronounced against lipid peroxidation. as assessed by TEARS form ation, while that of the crude extract was more effective in inhibiting pro tein oxidation. Both the crude extract and P3 fi action also partly protect s against radiation-induced loss of protein thiols and inactivation of supe roxide dismutase. The inhibitory effects of these active principles, at the concentration of 10 mu g/ml, are comparable to that of the established ant ioxidants glutathione and ascorbic acid. Hence our results indicate that ex tracts fi om A. racemosus have potent antioxidant properties in vitro in mi tochondrial membranes of rat liver. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.