In vitro Antileishmanial Activity of Some Ethiopian Medicinal Plants

INTRODUCTION: Leishmaniasis is a group of diseases caused by protozoan parasites, which remains a burden for developing countries. The lack of a vaccine as well as the emergence of resistance toward the recommended drugs pose a challenge for the control of the disease. This urges the demand for new antileishmanial agents to prevent and treat this disease. Consequently, four Ethiopian plants were selected and tested for their antileishmanial activity against two Leishmanial parasites. METHODS: Methanol (80%) was used to macerate the plant materials. In vitro antipromastigote activity of the crude extracts was then tested against promastigotes and axenically cultured amastigotes of Leishmania aethiopica and Leishmania donovani clinical isolates using Alamar Blue assay, and cell viability was measured fluorometrically. 1% DMSO and the media were used as a negative control while amphotericin B was used as a positive control. Furthermore, preliminary phytochemical analysis of the extracts was performed. RESULTS: From the four plants’ extracts, Ferula communis and Otostegia integrifolia showed better activity with IC(50) value of 11.38±0.55 and 13.03±0.87 µg/mL against L. aethiopica, respectively. However, the same plant extracts exhibited lower activity against L. donovani with IC(50) values of 23.41±2.32 and 17.24±1.29 µg/mL, respectively. O. integrifolia exhibited highest effect against amastigotes of L. aethiopica (IC(50): 16.84±0.65) and L. donovani (IC(50):14.55±0.38). F. communis resulted second highest in growth inhibition against amastigotes of L. aethiopica and L. donovani with IC(50) value of 14.32±0.54 and 31.12±0.19, respectively. The phytochemical analysis of the extracts indicated the presence of phenol, flavonoids, tannins, saponins, terpenoids, and alkaloids. CONCLUSION: The findings from this study demonstrate that crude extracts of F. communis and O. integrifolia showed promising antileishmanial activity against L. aethiopica and L. donovani that may be attributed to the presence of different secondary metabolites.