Some pharmacological effects of the leaf extracts of vernonia lasiopus and maesa lanceolata: plants traditionally used to treat common ailments in humans in East Africa

Abstract

Maesa lanceolata and Vernonia lasiopus are important traditional medicinal plants in E.Africa. M. lanceolata is used to treat malaria, dysentery, dermatosis, hypertension, ascariasis, difficult deliveries, etc. V. lasiopus is used to treat fever, abdominal pain, diarrhea, ascariasis and other ailments. Pharmacological effects of these plant extracts on the rabbit uterus and heart and guinea pig ileum were investigated in this study.

Methods

Leaves of M. lanceolata and V. lasiopus were collected from Mbarara District of Uganda. Extraction of dried plant material was done using petroleum ether, chloroform and ethanol. Effect of both plant leaf extracts of different concentrations was assessed on isolated guinea pig ileum, rabbit heart and rabbit uterus.

Results

The ether, choloroform and ethanolic extracts of M. lanceolata caused increase in the strength of contraction of isolated rabbit heart. The ether extract of M. lanceolata caused contraction of the isolated guinea pig ileum whereas the chloroform and ethanolic extracts did not. The extracts of V.lasiopus did not cause contraction of the isolated guinea pig ileum. Both M.lanceolata and V. lasiopus did not inhibit contraction of ileum induced by acetylcholine. The ethanolic extract of M.lanceolata elicited contractions of the uterus whereas the other fractions of M.lanceolata and V.lasiopus did not cause contraction of the uterus.

Conclusions These results show that the extracts of M.lanceolata have a positive inotropic effect on isolated rabbit heart, which could be of clinical benefit in cardiac failure and the use of this plant in treating hypertension may be harmful. The other results suggest extracts of M.lanceolata may induce abortion and could cause abdominal pain and diarrhea.