# Phenazinoates A‒E, five pairs of phenazine conjugates from a mangrove soil-derived Streptomyces strain OUCMDZ-4923

## TL;DR

Scientists discovered five pairs of new phenazine compounds from a soil bacterium and found two of them are effective against certain bacteria.

## Contribution

The discovery of five pairs of novel phenazine conjugates and their antibacterial activity against Gram-positive bacteria.

## Key findings

- Phenazinoates A and B showed antibacterial activity against four Gram-positive strains with low minimum inhibitory concentrations.
- The compounds were resolved into enantiomerically pure forms and their structures were confirmed using NMR and mass spectrometry.
- Semi-synthesis of compounds 1–3 was achieved using microwave-assisted solid acid catalysis.

## Abstract

Phenazinoates A–E (1–5), comprising five pairs of methyl saphenate conjugates with genistein, o-aminophenol, p-acetaminophenol and glycerol, were isolated from the fermentation broth of mangrove soil-derived Streptomyces sp. OUCMDZ-4923. Their structures were determined through comprehensive one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy, coupled with high-resolution electrospray ionization mass spectrometry. The absolute configurations of each isomer were established by comparing experimental electronic circular dichroism spectra with calculated counterparts. Based on the biosynthetic pathway analysis, compounds 1‒3 were semi-synthesized from the reactions of methyl (R)-saphenate with genistein, o-aminophenol, and o-formamidophenol, utilizing microwave-assisted solid acid catalysis. The compounds were resolved as enantiomerically pure forms and subsequently tested for antibacterial efficacy against six pathogenic bacteria. Phenazinoates A (1) and B (2) demonstrated bioactivity against four Gram-positive bacterial strains, with minimum inhibitory concentration values ranging from 0.78 to 3.13 μg/mL.

The online version contains supplementary material available at 10.1007/s13659-026-00597-0.