Antioxidant, free radical scavenging and liver protective effects of friedelin isolated from Azima tetracantha Lam. leaves

The aim of the present study was to evaluate the antioxidant, free radical scavenging and liver protective effects of friedelin isolated from Azima tetracantha Lam. leaves. In in vitro antioxidant study, the free radical scavenging effect of friedelin on 2,2-diphenyl-picrylhydrazyl (DPPH), hydroxyl, nitric oxide and superoxide radicals were evaluated. Friedelin showed very good scavenging effect on DPPH (IC50 21.1 mM), hydroxyl (IC50 19.8 mM), nitric oxide (IC50 22.1 mM) and superoxide (IC50 21.9 mM) radicals. Friedelin also showed strong suppressive effect on lipid peroxidation. In in vivo antioxidant study, CCl4 induced oxidative stress on rats produced significant increase in serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and lactate dehydrogenase (LDH) levels along with reduction in liver superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione peroxidase (GPx) levels. Pre-treatment of rats with friedelin at 40 mg/kg for 7 days restored these levels to normality and showed liver protection, comparable to the standard, silymarin (25 mg/kg). These results clearly demonstrated that friedelin possessed marked antioxidant and liver protective effects.