Anti-nociceptive activity of the aqueous extract of Erythrina velutina leaves.

Anti-nociceptive and anti-oedematogenic effects of the aqueous extract from the leaves of Erythrina velutina were tested through experimental models of nociception in mice and paw oedema induced by carrageenin in rats. The extract (300 and 600 mg/kg) did not change the carrageenin-induced paw oedema. In the hot plate test the extract also did not alter the latency time for mice liking the rear paws. Moreover, the extract (600 mg/kg) decreased by 96.5% the paw liking time in the second phase of the formalin test. This effect was antagonized by naloxone (5 mg/kg). In the acetic acid-induced writhing test, the extract (300 and 600 mg/kg) reduced the number of writhing by 88.8% and 96.4%, respectively. Our present results demonstrated that the crude extract from the leaves of E. velutina has anti-nociceptive but not anti-oedematogenic properties.