Antinociceptive and Anti-Inflammatory Effects of Hydroalcoholic Extract of Leaves of Piptadenia Gonoacantha (Mart.) Macbr. In Experimental Animal Models

Abstract

This study aimed to evaluate the anti-inflammatory and antinociceptive effects of hydroalcoholic extract of P.gonoacantha leaves (EPG). The toxic effect of the EPG was tested against A.salina in order to determine a secure dose for subsequent assays. The antinociception was evaluated using the acetic acid-induced writhing and hot plate tests in Wistar rats. The anti-inflammatory effect of EPG was evaluated by carrageenan-induced paw edema tests in rats. The bioassay with A.salina showed low toxicity of EPG (LC 50 =1,508mg/L). Oral administration of EPG (50, 100 and 150mg/kg) significantly decreased the number of acetic acid-induced writhes, around 61.3%, 71.8% and 64.9% respectively. However, EPG failed to prolong the latency time in the hot plate test, suggesting that EPG predominantly inhibits peripheral pain mechanisms. The oral administration of EPG at doses of 50 and 100mg/kg significantly inhibited paw edema at 3rd h after the injection of the phlogistic agent by 34.5% and 37.5%, respectively. These data suggest that EPG has both antinociceptive and anti-inflammatory activities, and these effects may be attributed to inhibition of COX-2 and prostaglandin release.