In vivo and in vitro evaluation of antidiarrhoeal properties of ethanol leaf and stem bark extract of Vitellaria paradoxa

Abstract

Diarrhoea is a common cause of deaths every year. It is a major public health problem in developing countries. Vitellaria paradoxa is used in Africa particularly in Nigeria and Togo in empirical treatment of diarrhoea. This study evaluated the effectiveness and mode of antidiarrhoeal activity of 50% ethanol leaf and stem bark extract of V. paradoxa in Wistar rats and isolated rabbit ileum. In vivo antidiarrhoeal effects of V. paradoxa at doses of 100, 200 and 400 mg/kg body weight (bw) were evaluated using castor oil-induced diarrhoea, castor oil-induced enteropooling, and gastrointestinal motility models in rats. Isolated rabbit ileum preparation was used to assess the in vitro effect of the extract on acetylcholine- and histamine-induced contractions. The extract significantly (P < 0.05) and dose-dependently inhibited castor oil-induced diarrhoea, intestinal transit was inhibited significantly (P < 0.05) at doses 200 mg/kg and 400 mg/kg while the volume of the intestinal content, Na⁺ and Cl⁻ levels were not significantly increased (P > 0.05) at doses of 100 and 200 mg/kg bw. However, significant (P < 0.05) increase in K⁺ level was obtained at 400 mg/kg bw. Osmotic gap was not significantly (P > 0.05) increased at all doses of extract. Acetylcholine-induced contraction was inhibited significantly (P < 0.05) by the extract with no significant inhibition of histamine-induced contraction on the isolated rabbit ileum. These results suggest that the leaf and stem bark of V. paradoxa may possess antidiarrhoeal activity through antimuscarinic effects of decreased peristalsis and prolonged gastric emptying time.