Effect of the ethanolic extract of Nauclea latifolia (Family: Rubiaceae) on the isolated uterus of non-pregnant rats

The plant Nauclea latifolia has been reported to be used by traditional healers to arrest pre-term labour. The ethanolic extract of the root of N. latifolia was screened for activity via agonist-induced contractions of uterine smooth muscles in non-pregnant female albino rats. The extract, at 0.1 and 0.2 mg/ml (final bath concentration), was tested against oxytocin (4×10 -5 to 8×10 -2 I.U/ml: final bath concentration), acetylcholine (0.04 to 40 μg/ml: final bath concentration) and ergometrine (0.05 to 100 μg/ml: final bath concentration) induced contractions invitro. The effect of the extract was compared to that of (0.004 μg/ml: final bath concentration) salbutamol and (0.004 μg/ml: final bath concentration) atropine. Both concentrations of the extract significantly shifted the concentration response curves of oxytocin ( P < 0.01), acetylcholine ( P < 0.0001) and ergometrine ( P < 0.0001) to the right with a slight depression of the Emax. This shift was more with the 0.2 mg/ml concentration, thus suggesting the possibility of a dose dependent action. There was no statistical significant decrease in Emax by 0.1 mg/ml of the extract, while the 0.2 mg/ml produced a significant depression ( P < 0.05) of the Emax, which like salbutamol could not be overwhelmed by higher concentrations of oxytocin. Similarly a significant reduction of the Emax of acetylcholine induced contractions was produced by 0.2 mg/ml, while both concentrations (0.1 and 0.2 mg/ml) produced significant ( P < 0.0001) reduction in Emax of ergometrine. It can thus be concluded that N latifolia root extract reduces oxytocin, acetylcholine and ergometrine-induced uterine contractions. These inhibitions were non-competitive. The result indicates an anti-abortifacient property.