Toxicity Studies on Aqueous-Methanol Pod Extract of <i>Vigna unguiculata</i> (Cowpea) in Wistar Strain Albino Rats

Abstract

Herbal preparation of Vigna unguiculata (cowpea) pod has long been used by a group of Hausa people from northern Nigeria called Yan tauri performers and traditional healers. This study was conducted to evaluate the toxicological effect of the extract in Wistar strain albino rats using biochemical, haematological and histopathological indices of toxicity. Acute toxicity (LD50) and sub-chronic toxicity studies were determined using the method developed by OECD. Twenty-five (25) rats were grouped into five(5) consisting of five(5) rats each, one of the groups served as control., Group II, III, IV and V were orally administered with the extract at a daily dose of 400 mg/kg, 800 mg/kg, 1200 mg/kg and 1600 mg/kg of the extract, respectively for 28 days. The LD50 of the extract was greater than 5000 mg/kg and its oral administration for 28 days did not produce significant changes (P˃0.05) on biochemical and haematological indices.  Histopathological evaluation revealed mild widening of Bowman’s capsule of animals administered with 1200 mg/kg and 1600 mg/kg of the extract. It can thus be concluded that the pod is non-toxic.

Keywords: Vigna unguiculata pod, Yan tauri performers, Aqueous-methanol extract, Acute and subchronic toxicity