Comparison of effects of margarite extract and recombinant human superoxide dismutase on paraquat-induced superoxide anion radicals in rat lung.

The effects of medicinal margarite extract and recombinant human superoxide dismutase (r-h SOD) on acute paraquat intoxication were examined in the rat lung. Forty-eight Sprague-Dawley rats under pentobarbital anesthesia were randomly assigned to one of four groups receiving i.v. injection of physiological saline (control), i.v. injection of 70 mg/kg paraquat, or i.v. injection of either 50 mg/kg of margarite extract or 50,000 unit/kg of r-h SOD 10 minutes before and 1 and 2 hours after an equivalent paraquat administration. Examination of lung superoxide anion radicals (O2-.), lipid peroxides, and histopathological changes showed that paraquat significantly increased superoxide anion radicals (383% of control) reacted with CLA-phenyl. Both margarite extract and r-h SOD decreased superoxide anion radicals to 119% and 83% of control, respectively. Margarite extract, rather than r-h SOD, significantly alleviated the paraquat-induced infiltration of polymorphonuclear leukocytes and macrophages into the alveolar walls. There were no significant inter-group differences in lipid peroxides in the lung. Component analysis showed that margarite extract was rich in L- and D-arginine. The scavenging mechanism of margarite extract may be related to L-arginine but needs to be further verified in the future study.