Antinociceptive properties of the methanolic extract obtained from Ipomoea pes-caprae (L.) R. Br.

Ipomoea pes-caprae is a medicinal plant used in many countries for the treatment of several ailments, including inflammatory and algesic processes. The present study describes the antinociceptive effects of the methanolic extract and two fractions obtained from aerial parts of this plant. The results indicated that both methanolic extract and two fractions (ethyl acetate and aqueous) exhibited considerable antinociceptive activity against two classical models of pain in mice. Methanolic extract presented a calculated ID50 value of 33.8 mg/kg, i.p. against writhing test and also inhibited both phases of pain (neurogenic and inflammatory) of the formalin test with ID50 of 37.7 and 12.5 mg/kg, i.p. for the first and second phase, respectively. Preliminary phytochemical analysis suggested the presence of steroids, terpenoids, alkaloids and flavonoids. These findings support, at least in part, the popular use of I. pes-caprae to treat dolorous processes.