Exploring the leaf fractions of Landolphia owariensis P. Beauv. for bioactive constituents, in vivo and beta hematin inhibitory antimalarial activity

Malaria remains a global challenge even though it is preventable and curable. The study assessed the chemosuppressive efficacy and in vitro antiplasmodial activity of the methanol fraction and subfractions of Landolphia owariensis leaves. The subfractions of Landolphia owariensis leaves obtained from column separation of methanol fractions were investigated for chemosuppressive activity in mice and in vitro antiplasmodial activity using a beta-hematin inhibition assay. Cytotoxicity was determined using the Brine shrimp lethality assay (BSLA), while the active constituents were identified using GC-MS and NMR spectroscopy. The subfractions showed significant chemosuppressive effects against P. berghei at 100 mg/kg when compared with the negative control. The CF5 showed the highest parasite clearance and a chemosuppression of 88.14%. The beta hematin inhibitory activities of C9 (IC50= 93.3 ± 0.05 μg/ml), C9A [octadecanoic acid (IC50 = 91.18 ± 0.07 μg/ml)] were comparable with chloroquine (IC50 = 89.7 ± 0.11 μg/ml). In the BSLA, C9 elicited medium cytotoxic activity (LD50 190.6 ± 0.03 μg/ml). The GC-MS analysis of C9 identified 50 compounds, and the NMR spectrum of C9A indicated the presence of octadecanoic acid. The study suggests that the plant contains constituents that may be explored in the fight against malaria.