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 de xtran-induced paw edema in rats. HAE (100 and 200 mg/kg, p.o.) and Cou m (5-20 mg/kg, p.o.) reduced in a dose-dependent manner the nociceptio n produced by acetic acid and formalin. In the hot plate test, HAE (10 0-400 mg/kg, p.o.) and Coum (5 and 10 mg/kg, p.o.) increased the laten cy time to the thermal stimulus 90 min after administration. While nal oxone 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 bu t not the dextran-induced edema. This antiedematogenic effect on the c arrageenan model was supported by histological studies performed in se ctions of the rat paw. In conclusion, the antinociceptive effects of H AE and Coum occur by a mechanism at least in part dependent on the opi oid system. The nitric oxide system possibly has also a role in the Co um nociception. In addition, the antiedematogenic activity is manifest ed in inflammatory processes dependent on polimorphonuclear cells.