Nitrile-Based Leishmania Cysteine Protease B Inhibitors with In Vivo Efficacy against Visceral Leishmaniasis
- 1São Paulo State University (UNESP) , , ,
- 2Physics Institute of São Carlos, University of São Paulo (USP) , , , ,
- 3Federal University of Latin American Integration (UNILA) , , ,
Abstract
Leishmaniasis remains a major neglected tropical disease with limited therapeutic options and increasing concerns regarding toxicity and drug resistance. Cysteine protease B (CPB), a key virulence factor in Leishmania spp., represents an attractive molecular target for the development of new antileishmanial agents. In this study, we designed and synthesized a series of dipeptidyl nitrile derivatives as reversible covalent CPB inhibitors and evaluated their biological activity in vitro and in vivo. Molecular docking performed in covalent mode demonstrated favorable accommodation of the compounds within the CPB active site, with the benzyl-containing derivatives showing the most favorable interactions. Among the series, compound 1 ((S)-tert-butyl (1-((cyanomethyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate) exhibited potent inhibition of recombinant LmCPB2.8ΔCTE (IC50 = 4.3 ± 0.2 μM) and strong activity against intracellular amastigotes of Leishmania infantum (EC50 = 3.9 ± 0.5 μM; SI ≈ 77) and Leishmania amazonensis (EC50 = 4.6 ± 1.6 μM; SI ≈ 65), surpassing miltefosine in selectivity. Compound 1 showed no cytotoxicity toward murine macrophages, no hemolytic activity, and good tolerability in the Galleria mellonella model. Oral administration of compound 1 to L. infantum-infected BALB/c mice (0.77 mg/kg/day for 5 days) resulted in a significant reduction in parasite burden in the liver and spleen (≈ 40–55%), even at a 10-fold lower dose than miltefosine. Although alterations in hepatic transaminases were observed, no evidence of renal dysfunction was detected. Collectively, these findings identify dipeptidyl nitriles as promising CPB-targeting scaffolds and position compound 1 as a lead structure for further optimization aimed at enhancing antileishmanial efficacy while minimizing host toxicity.
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BibTeX
@article{lima2026nitrilebased,
title = {{Nitrile-Based Leishmania Cysteine Protease B Inhibitors with In Vivo Efficacy against Visceral Leishmaniasis}},
author = {Jhonatan Santos de Lima and Michele Ferreira da Silva Mela and Juliana Romano Lopes and João Lucas Bruno Prates and Natalia Caroline Costa Coelho and Ana Clara Lunardi Yagi and Rafael Consolin Chelucci and Simone Michelan Duarte and Leonardo Luiz Gomes Ferreira and Adriano Defini Andricopulo and Gustavo Chagas Paulino and João Victor Marcelino de Souza and Bruna Cardinali Lustri Morgado and Paulo Ricardo da Silva Sanches and Eduardo Maffud Cilli and Jean Leandro dos Santos and Angela Maria Arenas Velásquez and Marcia Aparecida Silva Graminha},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c06826},
url = {https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c06826/5455837/Nitrile-Based-Leishmania-Cysteine-Protease-B},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Nitrile-Based Leishmania Cysteine Protease B Inhibitors with In Vivo Efficacy against Visceral Leishmaniasis
AU - Jhonatan Santos de Lima
AU - Michele Ferreira da Silva Mela
AU - Juliana Romano Lopes
AU - João Lucas Bruno Prates
AU - Natalia Caroline Costa Coelho
AU - Ana Clara Lunardi Yagi
AU - Rafael Consolin Chelucci
AU - Simone Michelan Duarte
AU - Leonardo Luiz Gomes Ferreira
AU - Adriano Defini Andricopulo
AU - Gustavo Chagas Paulino
AU - João Victor Marcelino de Souza
AU - Bruna Cardinali Lustri Morgado
AU - Paulo Ricardo da Silva Sanches
AU - Eduardo Maffud Cilli
AU - Jean Leandro dos Santos
AU - Angela Maria Arenas Velásquez
AU - Marcia Aparecida Silva Graminha
PY - 2026
DA - 2026/10/01
JO - ACS Omega
DO - 10.1021/acsomega.6c06826
UR - https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c06826/5455837/Nitrile-Based-Leishmania-Cysteine-Protease-B
AB - Leishmaniasis remains a major neglected tropical disease with limited therapeutic options and increasing concerns regarding toxicity and drug resistance. Cysteine protease B (CPB), a key virulence factor in Leishmania spp., represents an attractive molecular target for the development of new antileishmanial agents. In this study, we designed and synthesized a series of dipeptidyl nitrile derivatives as reversible covalent CPB inhibitors and evaluated their biological activity in vitro and in vivo. Molecular docking performed in covalent mode demonstrated favorable accommodation of the compounds within the CPB active site, with the benzyl-containing derivatives showing the most favorable interactions. Among the series, compound 1 ((S)-tert-butyl (1-((cyanomethyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate) exhibited potent inhibition of recombinant LmCPB2.8ΔCTE (IC50 = 4.3 ± 0.2 μM) and strong activity against intracellular amastigotes of Leishmania infantum (EC50 = 3.9 ± 0.5 μM; SI ≈ 77) and Leishmania amazonensis (EC50 = 4.6 ± 1.6 μM; SI ≈ 65), surpassing miltefosine in selectivity. Compound 1 showed no cytotoxicity toward murine macrophages, no hemolytic activity, and good tolerability in the Galleria mellonella model. Oral administration of compound 1 to L. infantum-infected BALB/c mice (0.77 mg/kg/day for 5 days) resulted in a significant reduction in parasite burden in the liver and spleen (≈ 40–55%), even at a 10-fold lower dose than miltefosine. Although alterations in hepatic transaminases were observed, no evidence of renal dysfunction was detected. Collectively, these findings identify dipeptidyl nitriles as promising CPB-targeting scaffolds and position compound 1 as a lead structure for further optimization aimed at enhancing antileishmanial efficacy while minimizing host toxicity.
SN - 2470-1343
ER -