Antidiarrhoeal activity of the ethyl acetate extract of Baphia nitida (Papilionaceae)

In our search for plants useful in the treatment of diarrhoea, we investigated the ethyl acetate extract of Baphia nitida (BN) using intestinal transit, enteropooling and gastric emptying tests in mice and rats. In the castor oil intestinal transit test, BN produced a significant (P < 0.05) dose dependent decrease in propulsion with peristaltic index (PI) values of 56.85 ± 6.76, 36.84 ± 3.04 and 31.98 ± 2.60%, respectively at doses of 100, 200 and 400 mg/kg vs. 89.33 ± 6.28% for control. The effect at 400 mg/kg was significantly lower than that of morphine, 10 mg/kg, s.c. (20.29 ± 3.78%), and was antagonized by isosorbide dinitrate, IDN (150 mg/kg, p.o.) but not by yohimbine (1 mg/kg, s.c.). This effect was not potentiated by atropine (1 mg/kg, s.c.). In the castor oil-induced diarrhoea test, BN produced a significant increase in onset of diarrhoea (103.40 ± 8.74, 138.80 ± 17.04 and 174.8 ± 29.04 min, 100 to 400 mg/kg, vs. 47.60 ± 8.76 min for control and 226.10 ± 12.57 min for morphine). The severity of diarrhoea (diarrhoea score) was dose dependently reduced (19.00 ± 2.26, 17.04 ± 1.89, 15.00 ± 2.05, 100 to 400 mg/kg, vs. 31.40 ± 2.11 for control and 7.7 ± 2.2 for morphine). This effect was not antagonized by IDN or yohimbine. The effect on severity was, however, potentiated by atropine. BN also reduced the number and weight of wet stools but did not have any significant effect on intestinal fluid accumulation and gastric emptying. Results obtained suggest that the ethyl acetate extract of Baphia nitida is endowed with antidiarrhoeal activity possibly mediated by interference with the l-arginine nitric oxide pathway and synergistic with antagonistic action on muscarinic receptors.