# Mechanistic Exploration of N,N′-Disubstituted Diamines as Promising Chagas Disease Treatments

## TL;DR

Researchers explored diamines as potential treatments for Chagas disease, finding some compounds effective against the parasite but needing further refinement.

## Contribution

The study introduces a new class of diamines with potential antiparasitic activity and investigates their mechanisms of action.

## Key findings

- Five diamines showed potent activity against T. cruzi amastigotes with short aliphatic linkers.
- Compound 3c inhibited polyamine transport in T. cruzi, suggesting a key mechanism.
- Fluorescent analogs confirmed intracellular uptake but lacked antiparasitic activity.

## Abstract

Introduction: Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a major public health concern due to the limited effectiveness of current treatments, especially in the chronic stage. Objective: Here, we wanted to advance a library of 30 N,N′-disubstituted diamines as promising antichagasic agents and gain insight into the mechanism of action. Methods: The library was evaluated for activity against the T. cruzi amastigote stage and trypanocidal efficacy. In addition, selected compounds were tested as potential polyamine transport inhibitors, and a fluorescent analog was employed to investigate compound internalization. Results: Five compounds exhibited potent activity (pIC50 > 6.0), particularly those with short aliphatic linkers (3–6 carbon atoms), suggesting a structure–activity relationship favouring shorter chains. Mechanistic studies showed that compound 3c strongly inhibited polyamine transport, a vital pathway in T. cruzi, though this was not a universal mechanism among active hits, indicating the potential for multiple targets. A fluorescent analog confirmed intracellular uptake in amastigotes but lacked antiparasitic activity, likely due to disrupted pharmacophoric features. Importantly, none of the compounds demonstrated trypanocidal activity in long-term assays, and some showed cytotoxicity, particularly in the benzyloxy-substituted series. Conclusions: These findings position N,N′-disubstituted diamines as a viable scaffold for Chagas disease drug discovery. However, further optimization is required to enhance selectivity, achieve trypanocidal effects, and better understand the underlying mechanisms of action.