Objective: To find out the protective action of methanolic extract of Rhinacanthus nasutus (R.
nasutus) on lipid peroxidation (LPO) activities and enzymatic antioxidants of liver in streptozotocin
(STZ) induced diabetic rats. Methods: Experimental diabetes was induced by a single dose of
STZ (50 mg/kg) through intraperitoneal injection. The oxidative stress was measured by tissue LPO
level and by enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione
peroxidase (GPx) in liver. Results: The raise in LPO levels with reduction in enzymatic activities
was the outstanding features observed in diabetic control rats. Administration of R. nasutus
(200 mg/kg body weight per day) for 30 days caused a significant reduction in LPO level in STZ
induced diabetic rats (group IV) when compared with diabetic control rats (group III). Moreover, R.
nasutus treated diabetic rats (group IV) showed significant increase in the activities of enzymatic
antioxidants when compared to diabetic control rats (group III). Conclusions: The results
obtained specify the ameliorating effects of R. nasutus in the role of oxidative stress created in the
experimental diabetic rats.