In Vivo Antiplasmodial Studies of Achyranthes Aspera Fractions and Molecular Docking Studies of Its Phytochemicals against Plasmodium Aspartic Proteases Targeted in Antimalarial Drug Design

Abstract

Evaluation of fractionated extracts of Achyranthes aspera L. as an alternative antimalarial therapy is essential due to the increasing resistance of Plasmodium falciparum to artemisinin. The side effects, limited accessibility, and high cost of current drugs have intensified interest in phytochemical screening of medicinal plants as sources of bioactive compounds with antimalarial properties. The mode of action of these phytochemicals remains largely unknown, necessitating an investigation into their in vivo antimalarial activity and in silico molecular interactions with Aspartic Proteases (Plasmepsin I, II, and IV), key drug targets in malaria treatment. The in vivo antiplasmodial activity of Achyranthes aspera fractions was assessed using Rane’s curative assay in a mouse model infected intraperitoneally with 1x107 Plasmodium berghei (NK-65) parasitized RBCs per milliliter, while LC-MS techniques analyzed the phytochemical composition. In silico drug-likeness studies, including PASS, molecular docking, ADME/Tox, and Lipinski’s rule of five, were conducted, with chemical compounds docked against Plasmepsins I, II, and IV. Rane’s curative test showed significant (P<0.05) parasite reduction, with the chloroform fraction achieving more than 50% reduction at 200 mg/kg b.wt. LC-MS identified 37 compounds, 11 of which demonstrated plasmepsin inhibitory activity. Docking studies predicted Rotundioside B and 4-(3-hydroxy-1-propenyl-2-) methoxy as the most effective, exhibiting favourable binding energies. In silico ADMET analysis confirmed good oral bioavailability and drug-likeness properties. Findings indicate that A. aspera shoot fractions possess antiplasmodial activity, with the chloroform fraction significantly reducing P. berghei burden in a manner comparable to artemisinin-based combination therapy (ACT), supporting its potential for pharmaceutical drug development.