An evaluation of antinociceptive effect of methanol extracts of Desmodium gangeticum (L.) Dc. stems and Benincasa hispida (Thunb.) Cogn. leaves on acetic acid-induced gastric pain in mice

Abstract

Desmodium gangeticum Duchesne (Fabaceae, local name: shalpani) is commonly found in the wild areas of Bangladesh. The leaves of the plant are used by folk medicinal practitioners for treatment of toothache, chest pains, and fungal infections. Benincasa hispida (Thunb.) Cogn. (Cucurbitaceae, local name: chal kumra) is cultivated for its edible fruits, which are cooked and consumed as vegetable. The fruits are used by the folk medicinal practitioners for treatment of tumor, gonorrhea, and helminthiasis. The leaves are used by the folk medicinal practitioners for relief from stomach pain. The objective of the present study was to evaluate the antinociceptive potential of stems of D. gangeticum and leaves of B. hispida in acetic acid-induced gastric pain with consequent abdominal constrictions in Swiss albino mice. Administration of methanol extract of stems of D. gangeticum was observed to cause dose-dependent and significant reduction of acetic acid-induced abdominal constrictions in mice. At the highest dose tested of the extract, namely 400 mg/kg body weight, the extract caused 52.6% inhibition of abdominal constrictions, when compared to control mice. In contrast, the standard antinociceptive drug, aspirin, caused 38.6% and 49.2% inhibitions of abdominal constrictions, when administered at doses of 200 and 400 mg/kg body weight, respectively. The results demonstrated that the methanol extract of stems of D. gangeticum was highly effective in the reduction of acetic acid-induced gastric pain, and as such validate the use of the plant in folk medicine for treatment of pain. The methanol extract of leaves of B. hispida also caused significant reductions in acetic acid-induced abdominal constrictions. However, the number of constrictions was lowest at the lowest dose tested of 50 mg/kg body weight, where it caused 48.1% inhibition in the number of abdominal constrictions (writhings). At higher doses, the percent inhibition of constrictions decreased progressively, and was 31.4% at the highest dose tested (400 mg/kg body weight). The results with B. hispida, although validating the use of the plant for pain, also suggest that any treatment with leaves of the plant for pain reduction purposes must be done with low doses. The progressive dose-dependent decrease of inhibitory activities is suggestive of presence of other constituents in the leaves, which may play an antagonistic role to constituents that modulate its antinociceptive effects.