Structure-Aided Computational Design of Triazole-Based Targeted Covalent Inhibitors of Cruzipain.

Area of Science:

• Medicinal Chemistry
• Parasitology
• Computational Chemistry

Background:

• Cruzipain (CZP) is a critical cysteine protease in *T. cruzi*, the parasite causing Chagas disease.
• Targeting CZP with inhibitors is a promising therapeutic strategy for Chagas disease.
• Developing effective inhibitors requires exploring diverse chemical spaces and ensuring biological activity translation.

Purpose of the Study:

• To design and identify novel 1,4-disubstituted 1,2,3-triazole analogues as potential targeted covalent inhibitors (TCIs) of cruzipain (CZP).
• To evaluate the synthesized compounds for their ability to inhibit CZP and exhibit anti-*T. cruzi* activity.
• To identify lead compounds for further preclinical development against Chagas disease.

Main Methods:

• Computer-aided drug design (CADD) including virtual screening of a large library (>75,000 analogues) using molecular docking and dynamics simulations.
• Combinatorial synthesis of selected candidates via Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC).
• In vitro enzymatic assays for CZP inhibition (IC50 determination) and anti-*T. cruzi* activity, alongside cytotoxicity assessments.

Main Results:

• A virtual library of over 75,000 triazole analogues was screened, leading to 48 candidates for synthesis.
• Twelve synthesized compounds selectively inhibited CZP with IC50 values in the low micromolar range.
• Four derivatives demonstrated significant anti-*T. cruzi* activity at 50 μM, with Ald-6 showing excellent efficacy and low cytotoxicity.
• Ald-6 exhibited complete in vitro activity translation from CZP inhibition to anti-parasitic effect.

Conclusions:

• The study successfully identified potent triazole-based CZP inhibitors with significant anti-*T. cruzi* activity.
• Ald-6 is a promising lead compound for Chagas disease treatment, warranting further preclinical investigation.
• The explored chemical space of 1,2,3-triazoles represents a valuable resource for discovering novel antichagasic agents.