Figure 3: Percentage inhibition of compounds 1– 9 (12.5 and 25 mg/kg, intraperitoneal) on acetic acid-induced writhing. Swiss albino mice were injected with compounds 1– 9 (12.5 and 25 mg/kg, intraperitoneal) and diclofenac sodium (12.5 and 25 mg/kg, intraperitoneal), which was used as the reference standard (D), or vehicle (control) 30 min before intraperitoneal injection of freshly prepared acetic acid [2% (w/v) in saline] at 10 ml/kg body weight. The mice were individually separated and were observed for 30 min. The percentage inhibition of writhes was calculated relative to the control group (acetic acid group). Each value represents the mean of the percentage inhibition of writhes ± SEM. *Significant difference from control at P < 0.05; #Significant difference from diclofenac sodium at P < 0. 05.