# Chlokamycins B–D: Chlorohydrin-Containing Polycyclic Tetramate Macrolactams with Cytotoxic Activity from the Marine Sponge-Derived Streptomyces xiamenensis 1310KO-148

## TL;DR

Scientists discovered new compounds from a marine sponge-derived bacteria that show promise in fighting cancer and bacterial infections.

## Contribution

The discovery of three new chlorohydrin-containing polycyclic tetramate macrolactams with cytotoxic and antibacterial properties.

## Key findings

- Chlokamycins B–D showed significant cytotoxic activity against 14 human cancer cell lines.
- The compounds exhibited antibacterial activity against Staphylococcus aureus and Micrococcus luteus.
- Structures were confirmed using NMR, HR-ESIMS, and ECD calculations.

## Abstract

Chemical investigation of the marine sponge-derived Streptomyces xiamenensis 1310KO-148 afforded six polycyclic tetramate macrolactams (PTMs), including three known compounds (1–3) and three previously undescribed chlorohydrin-containing analogues, chlokamycins B–D (4–6). Their planar structures were elucidated by extensive analysis of 1D and 2D NMR spectra and HR-ESIMS data, while the relative configurations were assigned using NOESY correlations. The absolute configurations were further confirmed by electronic circular dichroism (ECD) calculations. Compounds 3–6 exhibited significant cytotoxic activity against 14 human cancer cell lines (GI50 = 2.68–24.92 μM) and antibacterial activity against Staphylococcus aureus (MIC = 16.00–32.00 μg/mL) and Micrococcus luteus (MIC = 4.00–32.00 μg/mL) among six tested bacterial strains.