Integrated Experimental and Computational Evaluation of Naringenin and Zerumbone as Antiparasitic Agents Targeting Toxoplasma gondii and Leishmania major: Molecular Docking, Dynamics Simulations, and ADME Profiling.

BACKGROUND: Toxoplasmosis and Leishmaniasis represent significant global health burdens with limited treatment options and emerging drug resistance. Pteridine reductase 1 (PTR1), essential for folate metabolism in Leishmania parasites, constitutes a validated therapeutic target. This study evaluated the antiparasitic potential of naringenin and zerumbone through integrated experimental–computational approaches. METHODS: Antiparasitic activities against Toxoplasma gondii and Leishmania major were assessed using standardized MTT-based assays, with cytotoxicity evaluated against Vero and macrophage cells. Molecular docking employed Flare Cresset to investigate PTR1 binding interactions (PDB ID: 1E92). Molecular dynamics simulations utilized GROMACS for complex stability assessment. SwissADME predicted drug-likeness and pharmacokinetic properties. RESULTS: Zerumbone demonstrated antitoxoplasma activity (IC50 = 3.9 ± 0.5 µg/mL) compared to naringenin (IC50 = 11.2 ± 1.8 µg/mL), though both exhibited low selectivity indices (SI = 2.6 and > 2.2, respectively). Against L. major amastigotes, zerumbone showed moderate activity (IC50 = 14.7 ± 2.3 µg/mL, SI = 1.4), while neither compound inhibited promastigotes. Molecular docking and MD simulation revealed naringenin's PTR1 binding affinity (− 8.5 kcal/mol), occupying the substrate site through hydrogen bonds with Arg17, and ASN109. Zerumbone showed non-significant binding score. Both compounds exhibited favorable ADME profiles with no Lipinski violations, high gastrointestinal absorption, and no PAINS alerts, however, naringenin is predictable to be a P-gp substrate. CONCLUSION: Naringenin and zerumbone represent lead antiparasitic scaffolds requiring structural optimization to enhance selectivity, providing mechanistic insights for rational PTR1 inhibitor design.