Application of Virtual Screening Methods for the Identification of Novel Antileishmanial Therapies: Rational Discovery of Synthetic Inhibitors Targeting Triosephosphate Isomerase

Leishmaniasis is a neglected tropical disease of global relevance, and the emergence of parasite resistance highlights the urgent need for new therapeutic strategies. This study aimed to identify compounds with potential antileishmanial activity through virtual screening and in vitro validation. Seventy-seven Leishmania proteins were evaluated, leading to the identification of triosephosphate isomerase (TIM, PDB ID: 2VXN) as a promising therapeutic target. TIM was screened against more than 6,500 bioactive compounds, resulting in two potential inhibitors: ZINC9829539 and ZINC4270223. Molecular dynamics simulations revealed that both compounds established stable interactions with TIM, although with lower binding affinity compared to the crystallographic ligand phosphoglycolohydroxamic acid (PGH). In vitro assays were performed using THP-1-derived macrophages infected with intracellular amastigotes of Leishmania infantum, L. braziliensis, and L. amazonensis. The compounds exhibited cytotoxic concentrations between 15 and 30 µM, comparable to amphotericin B. Inhibitory concentrations ranged from 10.4-28 µM for ZINC4270223 and 22.1-26.6 µM for ZINC9829539. Selectivity indices ranged from 0.57-0.59 and 0.98-2.66, respectively, indicating limited parasite selectivity. Despite moderate efficacy, this study demonstrates the utility of virtual screening in identifying novel antileishmanial candidates. Further structural optimization may enhance the selectivity and potency of these compounds, making them more viable for therapeutic development against leishmaniasis.