Marine-derived fungi are a rich source of structurally diverse metabolites. Fungi produce an array of compounds when grown under different cultivation conditions. All the compounds (1–7) were evaluated for their anti-Vibrio activities.

Marine-derived fungi are a rich source of structurally diverse metabolites. Fungi produce an array of compounds when grown under different cultivation conditions. In the present work, different media were used to cultivate the fungus Aspergillus sp. ZA-01, which was previously studied for the production of bioactive compounds, and three new prenyl xanthone derivatives, aspergixanthones I–K (13), and four known analogs (47) were obtained.

Anti-Vibrio activity

The absolute configuration of 1 was assigned by ECD experiment and the Mo2(AcO)4 ICD spectrum of its methanolysis derivative (1a). Aspergixanthone I (1) showed the strongest anti-Vibrio activity against Vibrio parahemolyticus (MIC = 1.56 μM), Vibrio anguillarum (MIC = 1.56 μM), and Vibrio alginolyticus (MIC = 3.12 μM).

Seven prenyl xanthone derivatives, including three new compounds (13), were obtained from the marine-derived fungus Aspergillus sp. ZA-01 by using a shaken Czapek-Dox medium.

The absolute configuration of 1 was determined by the Mo2(AcO)4 ICD method. This work suggested that the OSMAC approach was an active pathway for the exploration of new bioactive molecules.

Aspergixanthone I (1) was obtained as a yellow powder, which showed five maximum UV absorbance bands at 228, 242, 264, 285, and 385 nm, indicating a prenyl xanthone nucleus for 1.

The molecular formula of C27H30O8 for 1 was deduced from the molecular ion peak [M + Na]+ at m/z 505.1827 (calculated for C27H30O8Na, 505.1833) in positive HRESIMS, which corresponded to 13 degrees of unsaturation.

Prenylxanthone derivatives (17) are a class of bioactive natural compounds that belong to the family of naturally occurring xanthones. This prenyl xanthone with a C-4 terpenoid-derived side chain was mainly isolated from fungi of the genus Aspergillus/Emericella.

Aspergixanthone K (3) was determined to have a molecular formula of C26H28O7using HRESIMS analysis. The 1D and 2D NMR data of 3 revealed that 3 represents a structural analog of 2, but it is missing the acetoxy group at C-25.