Phomporone A, a new cytosporone derivative from mangrove-derived fungus Phomopsis asparagi ZMU-35-1

A new polyketide, phomporone A (1), along with three related analogues, cytosporone P (2), cytosporone Q (3), and cytosporone E (4) were isolated from the mangrove-derived fungus Phomopsis asparagi ZMU-35-1. The chemical structures of these compounds were elucidated through comprehensive spectroscopic analysis, including 1D and 2D NMR and high-resolution electrospray ionisation mass spectrometry (HR-ESIMS), and by comparison with previously reported spectral data. The antifungal activities of compounds 1–4 were evaluated against a panel of phytopathogenic fungi. Compound 1 exhibited inhibitory activity against Botryosphaeria dothidea and Fusarium graminearum, with minimum inhibitory concentration (MIC) values of 50 and 100 μg/mL, respectively. Compound 2 showed moderate activity against Alternaria alternata with an MIC value of 100 μg/mL. Notably, compound 4 displayed the most potent and broad-spectrum antifungal profile, inhibiting B. dothidea, Valsa mali Miyabe & G. Yamada and A. alternata, and with MIC values of 6.25, 50, and 100 μg/mL, respectively.