Effects of methanol extract of Citrullus lanatus Thunb. (Curcubitaceae) fruit rind on experimentally-induced diarrhoea in Swiss-albino mice

This research aims at validating scientifically, the claim on use of Citrullus lanatus (watermelon) fruit rind as herbal medicine in treating diarrhoea in Northern Nigeria. Qualitative phytochemical screening was evaluated for presence of chemical constituents in methanol extract of Citrullus lanatus fruit rind (MECL). MECL was evaluated for oral acute toxicity in Swiss albino mice and established to be safe up to the highest dose of 5000 mg/kg. Effect(s) of extract was evaluated on models of experimentally induced diarrhoea in mice. Flavonoids, s teroids, alkaloids, saponins and triterpenes were present. Mice were grouped into five comprising of five animals each for all models of experimentally-induced diarrhoea; pre-treated group I (negative control) received orally, deionised water (10ml/kg), groups II, III and IV were administered 125, 250 and 500 (mg/kg) of MECL respectively. Group V (positive control) received loperamide (3 mg/kg) for castor oil-induced diarrhoea and fluid accumulation tests, while for charcoal meal test; group V received atropine sulphate (0.1 mg/kg) as positive. A significant (p≤ 0.01 and p≤ 0.001) non-dose dependent effect was elicited by extract, delaying onset of diarrhoea and reducing severity of diarrhoea respectively on castor oil-induced diarrhoea. MECL delayed propuls ive movement of charcoal along intestine, significantly (p≤ 0.05) decreasing volume (ml) of intestinal content compared to negative control of deionised water. Conclusively, MECL elicited antidiarrhoeal activity prolonging onset of diarrhoea, reducing severity of wet faeces, delaying movement of charcoal and decreasing volume of intestinal content, confirming the claim by herbal practitioners on its use in treating diarrhoea in Northern Nigeria. Keywords:  Citrullus lanatus ; Diarrhoea; Flavonoids; Intestinal motility