Acute Toxicity Studies and Evaluation of Analgesic Property of the Methanol Stem Bark Extract of Neocarya macrophylla

Abstract

The methanol stem bark extract of Neocarya macrophylla was screened for its analgesic activity using acetic acid-induced writhing in mice and formalin-induced pain in rats. The results of the study showed that the extract (60mg/kg, i.p.) decreased writhing response with 63.9% inhibition. The methanol extract also exhibited significant analgesic effect (P<0.05) in the formalin test which is in the same order of magnitude as that observed after administration of pentazocine (10mg/kg, i.p.) the standard drug. The intraperitoneal median lethal dose (LD50) of the methanol extract of N. macrophylla was found to be 283mg/kg in mice suggesting the plant is fairly toxic. The results of the study have shown that the methanol extract of N. macrophylla possesses analgesic activity which rationalizes the traditional use of the plant in the management of pain.