# Discovery of Antimicrobial Oligoindoles from a Cold-Seep-Derived Halomonas Strain

## TL;DR

Researchers discovered new antimicrobial compounds from a deep-sea microbe, which could lead to new antibiotics.

## Contribution

The discovery of two new indole dimers with strong antimicrobial activity from a cold-seep-derived Halomonas strain.

## Key findings

- Two new indole dimers, meribisindole A and B, were isolated and identified.
- Compounds 4, 7, and 8 showed potent inhibition against Fusarium oxysporum.
- Compound 11 exhibited significant growth inhibition against Staphylococcus aureus.

## Abstract

Mining bioactive secondary metabolites from microorganisms originating from deep-sea cold seep holds significant potential for discovering novel drug lead compounds. In this study, three known indole derivatives (1–3) were isolated from cold-seep-derived Halomonas meridiana OUCLQ22-B7. Subsequently, two-new indole dimers, meribisindole A (4) and meribisindole B (5), with nine known metabolites (6–14) were obtained via indole precursor feeding strategy. The structure of these compounds was elucidated via a combination of spectroscopic methods and circular dichroism (CD) measurement. Antimicrobial assays revealed that compounds 4, 7 and 8 exhibited potent inhibitory activity against Fusarium oxysporum CICC 41029 with minimal inhibitory concentrations (MICs) of 0.39−12.5 μg/mL, and compound 11 showed significant growth inhibition against Staphylococcus aureus CCARM 3090 with MIC value at 0.098 μg/mL.