Antinociceptive, anti-inflammatory and diuretic properties of Polygonum barbatum (L.) Hara var. barbata

The antinociceptive, anti-inflammatory and diuretic properties of the extracts of P. barbatum (L.) Hara var. barbata, Polygonaceae, at the doses of 200. and 400 mg/kg body weight; were evaluated in mice/rat models using, respectively, the acetic-acid-induced writhing method, the carrageenan-induced edema test and the Lipschitz method. In the. acetic-acid-induced writhing. test in mice, all extracts displayed a dose dependent analgesic effect. The most potent analgesic activity was observed with the petroleum ether extract at the dose of 400 mg/kg body weight with an inhibition of writhing response 46.8% compared to .62.2% for the positive control aminopyrine. Petroleum ether extract at the dose of 400 mg/kg body weight also displayed the highest,levels of anti-inflammatory activity after 2 h with the 39.3% inhibition. of paw edema, and this effect was better than the effect observed by the conventional anti-inflammatory agent phenylbutazone (maximum inhibition of 38.3% after 4 h). All extracts increased urine volume, in a dose-dependent manner, and the ethyl acetate extract. showed a significant level of diuresis comparable to that of the standard diuretic agent furosemide.