Mangrove-derived actinomycetes represent a rich source of novel bioactive natural products in drug discovery. In this study, four new polyene macrolide antibiotics antifungalmycin B-E (
1–
4), along with seven known analogs (
5–
11), were isolated from the
[...] Read more.
Mangrove-derived actinomycetes represent a rich source of novel bioactive natural products in drug discovery. In this study, four new polyene macrolide antibiotics antifungalmycin B-E (
1–
4), along with seven known analogs (
5–
11), were isolated from the fermentation broth of the mangrove strain
Streptomyces hiroshimensis GXIMD 06359. All compounds from this strain were purified using semi-preparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity-guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds exhibited broad-spectrum antifungal activity against
Talaromyces marneffei with minimum inhibitory concentration (MIC) values being in the range of 2–128 μg/mL except compound
2. This is the first report of polyene derivatives produced by
S. hiroshimensis as bioactive compounds against
T.
marneffei. In vitro studies showed that compound
1 exerted a significantly stronger antifungal activity against
T.
marneffei than other new compounds, and the antifungal mechanism of compound
1 may be related to the disrupted cell membrane, which causes mitochondrial dysfunction, resulting in leakage of intracellular biological components, and subsequently, cell death. Taken together, this study provides a basis for compound
1 preventing and controlling talaromycosis.
Full article
