[Analgesic effects of a raw extract of Ageratum conyzoïdes in the rat].

Ageratum conyzoïdes (AC) is a plant used in traditional medicine for mental and infection diseases, cephalgia, dyspnea, enteralgia and fever. The objective of this study is to investigate the antinoceptive properties of Ageratum conyzoïdes in the rat. The raw extract of AC is constituted by a lyophilisated powder obtained from leaves juice extract by using a crusher. A dilution of 1% in NaCl 0.9% is prepared with the lyophilisat. Several doses of this preparation; 25, 50, 100, 125, 150 mg/kg are injected intraperitonealy in animals. The wistar rats of both sexes weighting between 200-250 g are used for this study. Animal's behaviour is observed macroscopically; the spontaneous motor activity is measured by using Martin et al. method (1990), slightly modified. The number of squares crossed by animal is measured every ten minutes during thirty minutes. The rectal temperature is sampled and analgesic activity evaluated by the hot plate method and by the writhing syndrome induced by acetic acid. AC is compared here with morphine 7.5 mg/kg sc and control 0.9% NaCl ip. The student--Fisher t test is used for the statistical analysis of the results. The results obtained demonstrate that all doses equal or higher than 125 mg/kg cause mortality of rat. The doses of 50 and 100 mg/kg are selected for experiments. At these doses, AC cause: a precocious ataxia, a sedation and a slight ptosis. Six hours after injection, those effects disappear; a reduction of spontaneous motor activity.(ABSTRACT TRUNCATED AT 250 WORDS)