# Inhibitory Activity of Compounds Obtained from Streptomyces Against Trypanosoma cruzi

## TL;DR

This study explores compounds from Streptomyces bacteria that show promise as safe and effective treatments for Chagas disease.

## Contribution

The study identifies specific antiparasitic compounds from Streptomyces metabolites with low toxicity and high efficacy against Trypanosoma cruzi.

## Key findings

- Extracellular metabolites from Streptomyces strains showed LC50 values of 102–116 μg/mL against T. cruzi forms.
- Amphomycin and K-252c aglycone staurosporine were identified as active antiparasitic compounds.
- The metabolites were non-toxic to Artemia salina, non-cytotoxic to Huvecs, and non-hemolytic to human erythrocytes.

## Abstract

Chagas disease (ChD) caused by Trypanosoma cruzi remains a major public health concern, affecting approximately 8 million people worldwide. However, the number of undiagnosed cases is likely much higher. Existing treatments rely on benznidazole and nifurtimox which, despite their efficacy during the acute phase of infection, are often associated with severe side effects that can be life-threatening. As a promising alternative, actinomycetes—which are renowned for producing pharmacologically and industrially relevant metabolites—have demonstrated potent antimicrobial properties; however, their antiparasitic potential remains largely unexplored. This study evaluated the anti-trypanocidal activities of extracellular metabolites produced by Streptomyces thermocarboxydus strain Chi-43 (ST-C43) and Streptomyces sp. strain Chi-104 (S-C104) against epimastigote, trypomastigote, and amastigote forms of T. cruzi. The strains were cultured in ISP2 broth, and their extracellular metabolites were assessed via antiparasitic diffusion assays in microplates. The 50% lethal concentration (LC50) values ranged from 102 to 116 μg/mL against epimastigotes and trypomastigotes. The antiparasitic activity was confirmed through 3-(4,5-dimetiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based spectrophotometric assays and optical microscopy. Toxicity assays revealed that the extracellular metabolites were non-toxic to Artemia salina, non-cytotoxic to Huvecs, and non-hemolytic to human erythrocytes. Dose–response regression analysis showed statistically significant differences (p ≤ 0.05). LC-MS/MS analysis identified amphomycin and K-252c aglycone staurosporine as the active antiparasitic compounds. These findings highlight the potential of Streptomyces-derived extracellular metabolites as novel, selective, and safe anti-T. cruzi agents. Nevertheless, further studies in murine or preclinical models are needed to validate their efficacy and support future clinical applications for the treatment of ChD.