Anti-inflammatory activity and antioxidant role of Zanthoxylum nitidum bark

In the present study, the methanol extract of stem bark of Zanthoxylum nitidum (ZNME) was evaluated for its anti-inflammatory activity in acute (carrageenan, histamine and serotonin induced rat paw oedema) and chronic model (cotton pellet induced granuloma) along with reference drug indomethacin (10 mg/kg body wt. p.o.). The ZNME (75 and 150 mg/kg body wt. p.o.) exhibited significant activity (p < 0.001) against all phlogistic agents employed in a dose dependent manner. In chronic model also the ZNME caused a significant (p < 0.001) and dose dependent inhibition of granuloma formation. The ZNME was evaluated for its antioxidant properties by 1,1- diphenyl-2-picryl hydrazyl (DPPH) radical scavenging assay and in vitro lipid peroxidation induced by the Fe2+-ascorbate system in rat liver homogenate. In DPPH radical scavenging assay, the ZNME demonstrated marked and dose dependent free radical scavenging effect and the mean inhibitory concentration (IC50) of the ZNME was found to be 77.8 μg/ml, while the ascorbic acid (reference) exhibited 43.7 μg/ml. The ZNME effectively inhibited the lipid peroxidation in a dose related manner showing the IC50 value of 297.9 μg/ml, whereas the catechin (reference) showed 46.64 μg/ml. These findings reveal that the ZNME possessed promising acute and chronic anti-inflammatory and in vitro antioxidant actions in the tested models.