New polyhydroxanthones from the marine-associated fungus Penicillium sp. ZZ1750

[Display omitted] •Ergochromes C–G were isolated from the marine Penicillium sp. ZZ1750.•Ergochromes D–G were elucidated as new polyhydroxanthones.•Ergochromes C–G had moderate antibacterial and antifungal activities. Five polyhydroxanthones, including new natural product ergochrome C (1) and new compounds ergochromes D–G (2–5), together with 11 known compounds (6–16), were isolated from the marine-associated fungus Penicillium sp. ZZ1750. Structures of the polyhydroxanthones were determined based on their HRESIMS data, extensive NMR spectroscopic analyses, the results from single crystal X-ray diffraction, 13C NMR and ECD calculations. All isolated compounds were assayed for their antiproliferative activity against human glioma U87MG and U251 cells and antimicrobial activities in inhibiting the growth of methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans. The five polyhydroxanthones of ergochromes C–G (1–5) had moderate antimicrobial activities against MRSA and C. albicans with MIC values of 16–36 μg/mL. Only known compound calyxanthone (9) showed weak antiproliferative activity (IC50: 46.6 μM) against glioma U87MG cells.