Antimalarial Activities of a Therapeutic Combination of Azadirachta indica, Mangifera indica and Morinda lucida Leaves: A Molecular View of its Activity on Plasmodium falciparum Proteins.

BACKGROUND: The search for new antimalarial drugs remains elusive prompting research into antimalarial combinations from medicinal plants due to their cheapness, efficacy and availability. Azadirachta indica (AI), Morinda lucida (ML) and Mangifera indica (MI) have all been reported as potent antimalarial plants.

PURPOSE: This study evaluated the efficacy of an antimalarial combination therapeutics prepared from leaves of AI, ML and MI using in vitro, in vivo and molecular methods.

METHODS: Refined extracts of the plants combination was made by partitioning the aqueous extract of plants combinations (AI + MI, AI + ML, MI + ML, AI + MI + ML) using methanol and ethyl acetate consecutively. The resulting ethyl acetate partitioned fraction was evaluated for its antimalarial activity. Molecular docking and molecular dynamics simulation were employed to determine the possible mechanism of action of the constituent of the most active combination against four important P. falciparum proteins.

RESULTS: The result revealed that the refined extract from combinations AI + ML and MI + ML at 16 mg/kg bodyweight have the highest chemo-suppressive effect of 90.7% and 91.0% respectively compared to chloroquine's 100% at 10 mg/kg. Also, refined extract from MI + ML combination improved PCV levels significantly (p < 0.05) compared to controls. Molecular docking revealed oleanolic acid and ursolic acid as multiple inhibitors of plasmepsin II, hiso-aspartic protease, falcipain-2 and P. falciparum Eonyl acyl-carrier protein reductase with relative stability during 100 ns of simulation.

CONCLUSION: The study unveiled the potentials of ML and MI as good candidates for antimalarial combination therapy and further established their use together as revealed in folklore medicine.