Antinociceptive and antiedematogenic effects of the hydroalcoholic extract and coumarin from Torresea cearensis Fr. All.

This work studied the antinociceptive and antiedematogenic effects of the hydroalcoholic extract (HAE) and coumarin (Coum) from T. cearensis in experimental models of nociception in mice, and carrageenan-and dextran-induced paw edema in rats. HAE (100 and 200 mg/kg, p.o.) and Coum (5-20 mg/kg, p.o.) reduced in a dose-dependent manner the nociception produced by acetic acid and formalin. In the hot plate test, HAE (100-400 mg/kg, p.o.) and Coum (5 and 10 mg/kg, p.o.) increased the latency time to the thermal stimulus 90 min after administration. While naloxone partially reversed the antinociceptive effect of the HAE but not that of Coum, L-arginine reversed the antinociceptive effect of Coum in the formalin test. HAE (200 mg/kg, Po) and Coum (10 and 20 mg/kg, p.o.) significantly inhibited the carrageenan-induced edemas in rats but not the dextran-induced edema. This antiedematogenic effect on the carrageenan model was supported by histological studies performed in sections of the rat paw. In conclusion, the antinociceptive effects of HAE and Coum occur by a mechanism at least in part dependent on the opioid system. The nitric oxide system possibly has also a role in the Coum nociception. In addition, the antiedematogenic activity is manifested in inflammatory processes dependent on polimorphonuclear cells.