Antidiarrhoeal activity of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm ('African potato') aqueous extract in rodents.

This study investigated the antidiarrhoeal activity of Hypoxis hemerocallidea corm aqueous extract (APE) on experimentally-induced diarrhoea, gastrointestinal motility, intestinal transit and enteropooling in rodents. H. hemerocallidea corm aqueous extract (APE, 50-400 mg/kg, p.o.) produced dose-dependent and significant (p < 0.05-0.01) protection of rats and mice against castor oil-induced diarrhoea, inhibited intestinal transit and delayed gastric emptying. Like atropine (1 mg/kg, p.o.), APE (50-400 mg/kg, p.o.) produced dose-dependent and significant (p < 0.05-0.01) antimotility effect, and caused dose-related inhibition of castor oil-induced enteropooling in the animals. Like loperamide (10 mg/kg, p.o.), APE (50-400 mg/kg, p.o.) dose-dependently and significantly (p < 0.05-0.01) delayed the onset of castor oil-induced diarrhoea, decreased the frequency of defaecation and reduced the severity of diarrhoea in the rodents. Compared with control animals, APE (50-400 mg/kg, p.o.) dose-dependently and significantly (p < 0.05-0.01) decreased the volume of castor oil-induced intestinal fluid secretion, and reduced the number, weight and wetness of faecal droppings. APE (50-400 mg/mL) also produced concentration-related and significant (p < 0.05-0.01) inhibitions of the spontaneous, pendular contractions of the rabbit isolated duodenum, and attenuated acetylcholine (ACh, 0.1-5.0 microg/mL)-induced contractions of the guinea-pig isolated ileum. Although the precise mechanism of the antidiarrhoeal activity of APE could not be established, the results of this study indicate that APE possesses antidiarrhoeal activity. This finding supports the use of 'African potato' as a natural supplementary remedy for the treatment, management and/or control of diarrhoea in some rural communities of southern Africa. Copyright 2009 John Wiley & Sons, Ltd.