Comparative study of teratogenic potentials of crude ethanolic root bark and leaf extract of Rauwolfia vomitoria (apocynaceae) on the fetal heart

BACKGROUND: Rauwolfia vomitoria, a tropical shrub, is a medicinal plant used in the treatment of a variety of ailments. It is popular to the locals because of its anti-hypertensive and sedative properties. AIM: This is to find the probable teratogenic effects of ethanolic leaf and root bark extracts of Rauwolfia vomitoria on the morphological and histological features of the fetal heart. MATERIAL AND METHODS: Twenty five female rats weighing between 170-200g were used for this study. The rats were divided into five groups labeled A, B, C, D and E, with each group consisting of five rats. Pregnancy was induced by caging the female rats with sexually matured males. The presence of vaginal plug and tail structures in the vaginal smear the following morning confirmed coition, and it was regarded as day 0 of pregnancy. Group A was given sham treatment of distilled water. Group B and C received respectively 150mg/kg and 250mg/kg body weight doses of ethanolic leaf extract of Rauwolfia vomitoria, and those in groups D and E received respectively 150mg/kg and 250mg/kg body weight doses of ethanolic root bark extract of Rauwolfia vomitoria. These treatments were on days 7-11 of gestation (5 days) with the aid of an orogastric tube. On the day 20 of gestation, the rats were sacrificed and the fetuses examined for gross anomalies, preserved and latter process for histological studies. RESULTS: There were no mortality in this study, and no obvious gross malformations in the fetuses. Histological observations of the fetal heart showed marked distortion of the cardiac muscle nuclei and myocardial fibers in the treated groups particularly those whose mothers received 250mg/kg of the extracts. These effects were more pronounced in the groups whose mothers received the root extract when compared with the control and the groups whose mothers received the leaf extract. CONCLUSION: This result suggests that high doses of ethanolic leaf and root extracts of Rauwolfia vomitoria may be cardiotoxic to the developing rat's heart.