Antioxidant and Analgesic Activities of Pterocarpus marsupium Roxb

Abstract

The methanolic extract of the bark of Pterocarpus marsupium Roxb. (Papilionaceae) was screened for antioxidant activity in vitro and analgesic activity in mice, respectively. The in vitro antioxidant activity of the bark extract was evaluated using the 1,1-diphenyl-2-picrylhydrazyl assay, and the results were expressed as IC50. Ascorbic acid, used as a standard, had an IC50 = 34.0 μg mL−1, whereas the bark extract of P. marsupium had an IC50 = 53.0 μg mL−1. Use of the hot-plate method to study central analgesic activity of the bark extract in mice indicated that the bark extract of P. marsupium possesses the ability to significantly reduce pain threshold and also increase the response latency period to thermal stimuli in mice, similar to the reference drug pentazocine. The reaction time of mice was significantly increased to 2 hr with 500 mg mL−1 of bark extract, whereas pentazocine also increased reaction time to 2 hr with 5 mg kg−1. A decline in the reaction time beyond 3 hr was observed by the reference drug and bark extract.