For long, malaria has remained one of the most severe global public health concerns. Traditionally, in several African countries, Aspilia africana and Warburgia ugandensis have been in use for millennia to treat malaria. In the current study, A. africana calli (AaC), A. africana in vitro roots (AaIR), A. africana wild leaf (AaWL), and W. ugandensis stem bark (WuSB) were dried and pulverized. Fourier transform near-infrared (FT-NIR) spectroscopy was used to analyze the powdered samples, while 80% ethanolic extracts of each sample were assayed for antiplasmodial (against DD2, the chloroquine-resistant and 3D7, chloroquine-sensitive Plasmodium falciparum strains) and cytotoxicity activities. The most promising antiplasmodial activity (IC50 = 1.57 ± 0.210 µg/ml and 8.92 ± 0.365 µg/ml against respectively 3D7 and DD2 P. falciparum strains) and highest selectivity indices (43.90 ± 7.914 and 7.543 ± 0.051 respectively for 3D7 and DD2 P. falciparum strains) were evinced by WuSB. The highest total polyphenolic contents (367.9 ± 3.55 mgGAE/g and 203.9 ± 1.43 mgRUE/g for total phenolic and flavonoid contents, respectively) were recorded for WuSB and least for AaC. The antiplasmodial activities of the investigated medicinal plant tissues correlated positively with total polyphenolic content. The high selectivity indices of WuSB not only justify its traditional use for centuries to treat malaria, but also present it as a good candidate that could be exploited unearthing new antimalarial compounds. We recommend elicitation treatment for AaIR with moderate antiplasmodial activity against the DD2 P. falciparum strain to boost its secondary metabolite contents for optimal antimalarial activities.

Keywords: Antiplasmodial activity, Aspilia africana, Chloroquine sensitive, Chloroquine resistant, In vitro regenerated, Warburgia ugandensis