Anti-emetic activity of Grewia lasiodiscus root extract and fractions

Preparation of Grewia lasiodiscus (K Schum) root is used in African traditional medicine to treat fever, pains and emesis. A 70% aqueous methanolic extract of G. lasiodiscus root (Extract) was obtained and fractionated on column chromatography using solvents of increasing polarities to yield three fractions designated F1 to F3. The effect of the extract on pentobarbitone-induced hypnosis was evaluated in mice while the anti-emetic activities of extract and its fractions were studied on anhydrous copper sulphate-induced emesis in one-day-old chicks. The oral median lethal dose (LD50) of extract was studied and estimated to be 774 mg/kg. Extract at 25, 50 and 100 mg/kg produced a significant (p < 0.05) prolongation of sleeping time when compared with the control groups. Extract at 50, 100 and 200 mg/kg produced a significant (p < 0.05) decrease in copper sulphate-induced emesis in a dose-dependent manner. Fraction F1, at 50 mg/kg produced a 61.51% increase in emesis, while fractions F2 and F3 produced a 39.0 and 56.50% reduction in frequency of emesis, respectively. Our results suggest that the aqueous methanolic extract of G. lasiodiscus root and its fractions F2 and F3 have anti-emetic properties, which provide for the first time the rationale for its application in traditional medicine especially in the management of emesis.