Ian Oduori¹, Brian Nguti^2,

Malaria continues to be a profoundly impactful infectious disease responsible for a significant number of fatalities annually, primarily attributed to Plasmodium falciparum. The onset of antifolate drug resistance, notably characterized by mutations in Plasmodium falciparum dihydrofolate reductase (pfDHFR) and Plasmodium falciparum dihydropteroate synthase (PfDHPS), has significantly undermined the effectiveness of current therapeutic interventions, highlighting the urgent need for the development of new inhibitory agents. This research delineates a thorough in silico methodology that employs structure-based virtual screening, ADMET profiling, and molecular docking analyses to discern promising lead compounds targeting pfDHFR. A collection of 400 synthetic compounds was evaluated against the quadruple-mutant (N51I+C59R+S108N+I164L) pfDHFR and triple mutant PfDHPS crystal structures (PDB: 1J3K and 6JWZ). Drug-likeness criteria grounded in Lipinski's Rule of Five and ADMET assessments were utilized to refine the selection of candidates. Molecular docking analyses were conducted employing AutoDock Vina, and binding affinities were compared with those of the reference antifolate compounds pyrimethamine, cycloguanil, and sulfadoxine. Five lead compounds — ZINC000019331645, ZINC000426406087, ZINC000001154555, ZINC000001160009, and ZINC000013283483 — exhibited exceptional binding energies between −8.0 and −8.5 kcal/mol, indicating stronger predicted binding than the three reference drugs. (sulfadoxine, pyrimethamine, cycloguanil). The findings indicate that the identified scaffolds are promising candidates for additional experimental validation as novel antimalarial drugs, relevant for addressing drug-resistant malaria.

Malaria, Plasmodium falciparum, Molecular Docking, Virtual Screening, Antifolate Resistance, Drug Discovery, AutoDock Vina; ADMET, In Silico