Evaluation of the oxytocic activity of the ethanol extract of the roots of Alchornea cordifolia

Abstract

Alchornea cordifolia has been used traditionally for the induction of labour as an abortifacient. This study is aimed at verifying the folkloric use of the plant by investigating the effect of ethanolic extract of the root bark on the isolated stilboestrol pretreated uteri of non-pregnant female rats. The extract (1, 10, 50 g/l), oxytocin (4×10 −5 to 8×10 −3 g/l), acetylcholine (4×10 −6 to 8×10 −4 g/l), atropine (4×10 −3 g/l), phenoxybenzamine (4×10 −3 g/l), diphenhydramine(2×10 −1 g/l), and verapamil (12×10 −2 g/l) were used. Log concentration response curves were plotted and EC 50 and E max were obtained. One-way analysis of variance (ANOVA) with Dunnet corrections using Graph pad Instat version 2.05a was used for statistical analysis. The extract produced dose-dependent contraction of the uterus. Its potency was less than that of oxytocin and acetylcholine (P<0.05), but the E max showed no significant difference (P>0.05). The E max values of the extract in the presence of all antagonists were significantly reduced (P<0.01). The EC 50 in the presence of atropine showed no significant increase (P>0.05); however, in the presence of phenoxybenzamine, the increase was significant (P<0.05). The presence of diphenhydramine and verapamil produced an inhibition such that the EC 50 was unattainable. A. cordifolia stimulates the uterus possibly by binding to alpha-adrenergic or histaminergic receptors or both. This indicates the existence of active principles in the plant, which may be responsible for some of the applications in traditional medicines as an abortifacient and in the induction of labour.