ANTI-NOCICEPTIVE ACTIVITIES OF AQUEOUS EXTRACT FROM THE STEM BARK OF DRYPETES GOSSWEILERI (EUPHORBIACEAE) IN MICE AND RATS
This study was carried out to evaluate the analgesic properties of the aqueous extract of Drypetes gossweleiri (Euphorbiaceae). The antinociceptive action was assayed in several experimental models: acetic acid; formalin in mice and pressure induced by analgesiometer in rats. The effect following paracetamol-codeine pre-treatment was also studied. The aqueous extract at doses of 100 and 200 mg/kg significantly reduced the nociceptive effect induced by acetic acid administered intraperitoneally (p<0.01 and p<0.001) with percentage inhibition of constriction of 45.79 and 66.06% respectively. In the formalin test and in the first phase, the extract at dose 200 mg/kg significantly reduced pain sensation (p<0.01) with a percentage inhibition of 47.41%. In the second phase of the test, the effect of the extract was dose dependent on pain sensation, with percentage inhibition of 36.27% for 100 mg/kg, 55.84 % for 200 mg/kg, and 65.4% for 400 mg/kg of plant extract. In the test on pain induced by pressure, doses of 100, 200 and 400 mg/kg of the plant extract significantly reduced pain sensation with a maximum inhibition of 54.44% observed with the dose of 200 mg/kg. These results show that the stem bark of Drypetes gossweileri might possess analgesic properties