# Novel Hit Compounds Against a Neglected Sexually Transmitted Infection: Synthesis and Trichomonacidal Activity of 1,3-Thiazolidin-4-One Derivatives

## TL;DR

This study explores new compounds that effectively fight Trichomonas vaginalis, a common sexually transmitted infection, with promising safety and drug potential.

## Contribution

The study introduces 1,3-thiazolidin-4-one derivatives as novel trichomonacidal agents with strong activity and low cytotoxicity.

## Key findings

- Seventy percent of the compounds showed over 80% antiparasitic activity at 100 μM.
- Compounds 4a, 4b, and 4f exhibited IC50 ≤ 20 µM and no cytotoxicity to mammalian cells.
- Molecular docking predicted strong interactions with T. vaginalis enzymes like lactate dehydrogenase and purine nucleoside phosphorylase.

## Abstract

Background: Infections caused by the protozoan Trichomonas vaginalis affect millions of people worldwide and are responsible for one of the most common sexually transmitted diseases. Despite the efficacy of 5-nitroimidazoles like metronidazole, concerns regarding widespread resistance and the absence of viable alternatives for specific patient populations necessitate the development of structurally diverse pharmacological agents. In this study, we investigated the antiparasitic activity of 1,3-thiazolidin-4-one derivatives against T. vaginalis. Methods: Thiazolidines were synthesized via multicomponent reaction (MCR) using one-pot methodology and tested in vitro against the parasite and mammalian cell lines. Results: Seventy percent of the compounds showed more than 80% antiparasitic activity at 100 μM, with compounds 4a, 4b, and 4f exhibiting IC50 ≤ 20 µM. None of the molecules exhibited cytotoxic against Vero CCL-81 and HeLa cells. Evaluation of the structure–activity relationship (SAR) indicates that the substituent at the nitrogen position of the heterocycle may be involved in the antiparasitic effect of these compounds. In silico studies also revealed that the three compounds possess adequate oral bioavailability and do not present mutagenic, tumorigenic or irritating risks. Finally, molecular docking predicted strong interactions of compounds 4a, 4b, and 4f with T. vaginalis enzymes lactate dehydrogenase and purine nucleoside phosphorylase; compound 4f also interacted with methionine Ƴ-lyase. Conclusions: These preliminary results suggest that 1,3-thiazolidin-4-ones are promising scaffolds for developing new trichomonacidal agents.