“Hydroethanol extract and triterpenoids of Senegalia ataxacantha show antiplasmodial activity and the compounds are predicted to inhibit parasite lactate dehydrogenase (pfLDH) as indicated by molecular docking studies”

Malaria claims over 600,000 deaths annually with a disproportionately high burden in the WHO African Region. The development of parasite resistance has warranted the search for novel anti-plasmodial drug candidates. This research aimed at validating the efficacy of Senegalia ataxacantha and tracking down its bioactive constituents. In vivo antiplasmodial activity of the extract was assessed using suppressive and curative protocols. Yeast-induced pyrexia was employed to evaluate the antipyretic activity of the extract. In vitro anti-plasmodial activity of isolated compounds was done using SYBR green I fluorescence assay on chloroquine sensitive (3D7) and resistant (Dd2) strains of P falciparum. In silico pharmacokinetic and interactions with parasites lactate dehydrogenase predictions of isolated compounds was conducted through molecular docking studies. Ethanol (70 %) extract of the plant showed in vitro and in vivo anti-plasmodial effect. The extract demonstrated significant ( p < 0.05) dose-dependent suppression of 63.39 % and 63.32 % respectively at the highest dose (300 mg kg -1 ). Artesunate (4 mg kg -1 /day) had considerably better curative potential (85.25%). The compounds showed in vitro anti-plasmodial activity in the order lupeol> friedelin/ friedelinol mixture>friedelin>β-sitosterol based on IC 50 measurement. Friedelinol and lupeol exhibited higher binding affinities with pfLDH compared to Chloroquine. The extract and acetaminophen (positve control) showed significant ( p < 0.05) reduction in rectal temperature compared to the control group. In silico studies of the compounds revealed moderate interactions with some cytochrome P450 metabolizing enzymes. S. ataxacantha stem extract shows anti-plasmodial and antipyretic activities which may be due to its pentacyclic triterpenoid constituents inhibiting pfLDH.