Evaluation of the anti-diarrheal activity of 80% methanol extracts and the solvent fraction of the leaves of Withania somnifera (L.) Dunal (Solanaceae) in mice

Background: The leaf of Withania somnifera has been used for the treatment of diarrhea without evaluation of its efficacy. This study was aimed to evaluate the antidiarrheal activity of 80% methanol extract and the solvent fraction of Withania somnifera leaf in mice.Materials and Methods: The extraction was done using a cold maceration technique. The antidiarrheal activity was investigated on the castor oil-induced diarrhea, castor oil-induced gastrointestinal transit tests, and castor oil-induced enteropooling models. The mice were randomly grouped into negative control received 10ml/kg 2% tween-80 in distilled water, positive control received 3mg/kg loperamide, and group III - V received 100 mg/kg, 200 mg/kg, and 400mg/kg of the extract orally.Result: The crude extract, aqueous, and n-butanol fractions significantly delayed the onset of diarrhea at 200mg/kg and 400mg/kg doses. All three doses of the crude extract showed significant activity on the three models (castor oil induced diarrhea, castor oil induced gastro-intestinal motility, and castor oil-induced enteropooling test), whereas the aqueous and n-butanol fractions revealed a significant result at 200mg/kg and 400mg/kg. The phytochemical screening showed that flavonoids, tannins, alkaloid, phenols, saponin, terpenoids, and steroid were presented in the crude, flavonoid, phenol, tannin, saponin, alkaloid, and steroid were possessed in aquas fraction, while the n-butanol fraction contained flavonoid, tannins, phenols, alkaloid and terpenoids, the chloroform fraction showed the presences of flavonoids, steroids and terpenoids. The acute oral toxicity test revealed that the crude extract was safe at 2000 mg/kg.Conclusion: This study demonstrated that the crude and fractions of Withania somnifera leaf has antidiarrheal activity and supports the folklore use of the plan for the treatment of diarrhea.