To investigate on the anti-diarrhoeal properties of the aqueous and methanol leaf extracts of Combretum racemosum in rats. Preliminary phytochemical analysis and acute toxicity study were conducted using standard methods. The effect of the aqueous and methanol extracts of C racemosum on gastrointestinal transit was determined in rats using the Charcoal meal model. The effect of both extracts on castor oil-induced diarrhea was determined. The anti-diarrhoeal activity of the extracts was investigated in the setting of prostaglandin E2-induced enteropooling in rats. The effect of the extracts on the spontaneous rhythmic contractions of the isolated rabbit jejunum and on acetylcholine and histamine-induced contractions of the guinea-pig ileum were also investigated. Phytochemical analysis revealed the presence of alkaloids, glycosides, carbohydrates, reducing sugars, proteins, saponins, steroids, flavonoids, and terpenoids. Acute toxicity test showed LD50 of >5000mg/kg body weight in mice. A significant reduction in gastrointestinal transit by both extracts was observed when compared with 2.5% dimethylsulphoxide (DMSO) and atropine respectively (p<0.01). The extracts inhibited the spontaneous rhythmic contractions of the rabbit jejunum in a dose-dependent and reversible manner and also inhibited acetylcholine and histamine-induced ileal contractions. Significant inhibition of prostaglandin E2-induced enteropooling was observed upon treatment with both extracts in a manner comparable to that of the standard antidiarrhoeal drug (loperamide). Both extracts showed significant anti-diarrhoeal activity against castor oil-induced diarrhea. The extracts of Combretum racemosum leaves have significant anti-diarrhoeal activity and justifies its traditional use in folk medicine for the treatment of diarrhoea.
