Potent antitrypanosomal compounds from Guiera senegalensis inhibit Trypanosoma brucei

Introduction: African trypanosomiasis is a disease caused by Trypanosoma species. Chemotherapy is limited by several factors. Thus, this study’s goals were to assess Guiera senegalensis leaf extracts’ in vitro antitrypanosomal activity against Trypanosoma brucei brucei and to use gas chromatography–mass spectrometry (GC–MS) analysis to isolate, characterize, and identify potential bioactive compounds. Materials and methods: Parasite growth inhibition was assessed at defined concentrations of aqueous methanol leaf extract and fractions of Guiera senegalensis. Fractions exhibiting the highest activity were further analyzed for their chemical composition using GC–MS to identify putative bioactive constituents. Results: Fractions A3, A4, A7, A8, and TA inhibited cell growth by 100% at concentrations of ≥10 µg/ml. Whereas A9, A10, TA2, and TA3 produced complete growth inhibition at concentrations of ≥40 µg/ml. Further screening of A3, A4, A7, A8, and TA at lower concentrations showed that EC50 values of A7 and A8 were in the range of 0.12 µg/ml to 0.65 µg/ml and 0.13 µg/ml to 0.63 µg/ml respectively, while the EC50 values for A3, A4, and TA were 1.3 µg/ml to 2.6 µg/ml, 1.1 µg/ml to 2.3 µg/ml, and 2.9 µg/ml to 5.3 µg/ml respectively. GC–MS analysis of the most potent fractions revealed compounds belonging predominantly to fatty alcohols, fatty acids, terpenoids, hydrocarbons, steroidal derivatives, alkaloids, and oxygenated heterocycles. Conclusions: The present findings move the field beyond descriptive phytochemical screening by providing quantitative, cidal, and concentration-resolved evidence of strong antitrypanosomal activity, thereby strengthening the case for this plant as a source of lead compounds against African trypanosomiasis.