Study of antinociceptive effect of isolated fractions from Petiveria alliacea L. (tipi) in mice.

The acetate (FA), hexanic (FH), hydroalcoholic (FHA) and precipitated hydroalcoholic (FHAppt) fractions from the root of Petiveria alliacea L. were evaluated for antinociceptive effect using the abdominal constriction induced by acetic acid, hot-plate, formalin tests. The open field and rota rod tests were used to evaluate psychomotor function and myorelaxant activity. The fractions were administered intraperitoneally in mice at doses of 100 and 200 mg/kg. Inhibitions of abdominal constrictions were observed with all doses of the fractions, as compared to control. FH and FHAppt, at both doses, reduced the nociception produced by formalin in the 1st (0-5 min) and 2nd (20-25 min) phases, however FHA (100, 200 mg/kg) and FA 200 mg/kg presented significant inhibition on the 1st and 2nd phases, respectively, of this test. A reduction of the locomotor activity was observed in the open field test with all the fractions. These fractions failed to affect the motor coordination in the rota rod test. Results showed that the different fractions of Petiveria alliacea L. have different antinociceptive potentials as demonstrated in the experimental models of nociception in mice, supporting folk medicine use of this plant.