# Antimycobacterial and Nitric Oxide Production Inhibitory Activities of Goyazensolide and Centratherin Isolated From Eremanthus crotonoides by High‐Speed Countercurrent Chromatography

## TL;DR

Two compounds from Eremanthus crotonoides show strong antimycobacterial and anti-inflammatory effects, especially against tuberculosis strains.

## Contribution

First isolation of goyazensolide and centratherin from E. crotonoides using HSCCC and their evaluation against virulent M. tuberculosis strains.

## Key findings

- Goyazensolide and centratherin showed potent antimycobacterial activity against M. tuberculosis H37Rv with MIC50 values of 1.5 and 2.5 µg/mL.
- Both compounds exhibited strong nitric oxide inhibition with IC50 values of 0.45 and 0.34 µg/mL, respectively.
- The compounds showed low cytotoxicity and reduced activity against the hypervirulent M299 strain.

## Abstract

In this study, bioassay‐guided fractionation of the ethanolic extract from Eremanthus crotonoides leaves enabled the isolation of two bioactive sesquiterpene lactones, centratherin and goyazensolide, which were evaluated for their antimycobacterial and anti‐inflammatory properties. The extract exhibited MIC50 values of 42.0 ± 0.1 and 39.0 ± 0.1 µg/mL against Mycobacterium tuberculosis H37Rv and the hypervirulent M299 strain, respectively, along with notable NO inhibitory activity. Fractionation by high‐speed countercurrent chromatography (HSCCC), followed by purification also employing HSCCC, yielded centratherin and goyazensolide, representing the first report of their isolation from E. crotonoides using this technique. These compounds showed potent activity against H37Rv (MIC50 = 1.5 ± 0.1 and 2.5 ± 0.1 µg/mL, respectively) but markedly reduced activity against M299 (MIC50 = 92.7 ± 0.1 and 90.6 ± 0.1 µg/mL). Both compounds also exhibited IC50 values of 0.45 ± 0.1 and 0.34 ± 0.1 µg/mL for nitric oxide inhibition, with low cytotoxicity. Collectively, these findings provide the first evidence of the antimycobacterial potential of these compounds against virulent M. tuberculosis strains and underscore their promise as potential drug candidates.