ABSTRACT
In this study, evaluation of the antidiarrhoeal effect of aqueous fruit extract of Phoenix dactylifera L. on the histology of the small intestine of Wistar rat, a preliminary phytochemical screening of the aqueous fruit extract of Phoenix dactylifera (AEPD) revealed the presence of alkaloids, tannins, saponins, flavonoids and carbohydrates. Oral acute toxicity study (LD50) of the extract was conducted and found to be greater than 5000mg/ kg in Wistar rats. The antidiarrhoeal activity of the extract was evaluated on castor oil induced diarrhoea, gastrointestinal transit and enteropooling in Wistar rats. In the castor oil induced diarrhoeal study, the following experiments were conducted - determination of standard drug (loperamide) antidiarrhoeal dose between the doses of 3mg/kg and 5mg/kg loperamide in Wistar rats; antidiarrhoeal activity of the extract in prophylactic and therapeutic administrations in Wistar rats; antidiarrhoeal activity of the combined administration of extract and loperamide in prophylactic and therapeutic administrations in Wistar rats. In the extract prophylactic and therapeutic treatments, the Wistar rats were divided into four (5) groups (n= 5), group 1 served as the control; group 2 was administered loperamide (5mg/kg) as standard drug; groups 3 and 4 administered AEPD (1000mg/kg and 2000mg/kg respectively). In the combined administration prophylactic and therapeutic treatments, the Wistar rats were divided into four (4) groups (n= 5), group 1 served as the control; group 2 was administered loperamide (5mg/kg); groups 3 and 4 were administered 1000mg/kg AEPD + 5mg/kg loperamide and 2000mg/kg AEPD + 5mg/kg loperamide respectively. In the gastrointestinal transit and enteropooling studies, the Wistar rats were divided into four (4) groups (n= 5), group 1 served as control, groups 2 and 3 served as extract low and high dose; administered AEPD (1000mg/kg and 2000mg/kg respectively) and group 4 served as the standard drug group administered loperamide (5mg/kg). The extract and the combined treatment (AEPD + standard drug) showed inhibitory activity against castor oil induced diarrhoea in both prophylactically and therapeutically treated animals. A significant reduction (p<0.05) in the gastrointestinal motility in charcoal meal test and decreased volume of intestinal fluid accumulation (enteropooling) induced by castor oil compared to the control was observed. The histoarchitecture of the jejunal mucosae of the Wistar rats were also preserved as compared to the control that manifested with severe histoarchitectural distortion. Inhibition of the severity of diarrhoea, gastrointestinal propulsion and fluid secretion by the extract and the combined treatment of extract + standard drug suggest that the extract might exert its antidiarrhoeal activity by antisecretory mechanism ascribed to the phytochemicals present in the extract.