Brachystegia eurycoma harms (Fabaceae) stem bark extract modulates gastrointestinal motility in animal models

Brachystegia eurycoma, a plant in the Fabaceae family has been used ethno- medicinally in the softening of bulky stool, and has been associated with protection of colonic cancer. This study was therefore aimed at the evaluation of possible modulatory effect of the stem bark extract of Brachystegia eurycoma (BE) on gastrointestinal motility. The in vivo activity of BE on gastrointestinal motility was evaluated using the following experimental models viz: normal intestinal transit, castor oil- induced diarrhoea, and intestinal fluid accumulation tests in rodents. The in vitro activity on isolated intestinal motility was also investigated on the following parameters viz: spontaneous, acetylcholine- and high KCl-induced intestinal contractions. BE (100, 300 and 700 mg/kg p.o.) produced a moderate decrease in normal intestinal transit while significantly (P < 0.05) reducing the propulsive movement in castor oil-induced diarrhoea compared with the control group (5% tween 80 10 ml/kg, p.o.). The extract also produced a dose-dependent, significant increase in the onset of diarrhoea. BE (100, 300 and 700 mg/kg) additionally reduced the diarrhoea score, number and weight of wet stools. The in-vivo antidiarrheal index (ADIin-vivo) of 37.14% produced by the extract at the dose of 300 mg/kg was lower compared to that produced by loperamide 5 mg/kg (54.74%). In vitro results revealed that the crude extract, the aqueous and chloroform fractions inhibited both spontaneous, acetylcholine and KCl-induced contractions in a concentration-dependent manner. In conclusion, the stem bark extract of Brachystegia eurycoma has been shown to exhibit antidiarrheal activity, possibly mediated by anti-muscarinic receptor activity or interaction with calcium channels