In vitro anti-trypanosomal activity of crude extract and fractions of Trichoscypha acuminata stem bark, Spathodea campanulata flowers, and Ficus elastica lianas on Trypanosoma brucei brucei

The low therapeutic index of available trypanocidal drugs and the increasing emergence of resistant Trypanosoma parasites indicate the urgent need to develop new strategies for trypanosomiasis control. One such strategy is the screening of medicinal plants as sources of new lead compounds. Trypanosoma brucei brucei is a sub-species only infecting animals and thus largely used to screen anti-trypanosomal potential of various substances. Therefore, the present study investigates the anti-trypanosomal activity of crude extract, hexane, dichloromethane, ethyl acetate, and aqueous fractions of Spathodea campanulata P. Beauv. flowers, Trichoscypha acuminata Engl. stem bark, and Ficus elastica Roxb. Ex Hornem lianas using the Alamar Blue assay. Overall results showed that the crude extract of T. acuminata, S. campanulate, and F. elastica did not significantly reduce the viability of Trypanosoma brucei brucei at the tested concentration of 25 µg/mL. However, the hexane and dichloromethane fractions of T. acuminata and the hexane fraction of F. elastica exhibited viability percentages of 23.2 ± 10.5, 18.2 ± 9.7, and 20.1 ± 13.1% with IC50 values of 5.5, 5.0, and 17.5 µg/mL, respectively. Further research to identify compounds responsible for the observed activity and their mechanisms of action towards new leads in parasitical drug discovery is needed.