Exploration of Analgesic Activity of the Ethanolic Extract of Erythrina variegate Bark

The aim of this study was to evaluate analgesic activity of the ethanolic extract of the bark of Erythrina variegata . The analgesic potential of the extract was evaluated using acetic acid-induced writhing test for peripheral analgesic activity and tail immersion, hot plate, formalin and glutamate test at 50, 100, and 200 mg/kg body weight doses. In analgesic activity tests, the extract at the doses of 50, 100, and 200 mg/kg b.w. produced a remarkable increase in pain threshold in a dose dependent manner. In acetic acid induced writhing test, the inhibitory effect was to be parallel to the reference drug diclofenac sodium. The extract showed 18.89% writhing inhibitory effect at the dose 200 mg/kg b.w., whereas diclofenac sodium showed 79.42% inhibition of writhing at a dose of 10 mg/kg b.w. The results of tail immersion and hot plate test also showed potential analgesic activity of the extract which is also comparable to the standard drug morphine (5 mg/kg b.w.). In formalin test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 47.80% inhibitory effect in late phase, whereas the reference drug morphine showed 63.64% inhibitory effect on licking of the hind paw. In glutamate test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 68.07% inhibitory effect in late phase, whereas the reference drug diclofenac sodium showed 61.53% inhibitory effect on licking of the hind paw. In conclusion, it can be said that the plant part have potential analgesic activity and may be used to relief pain.