Structurally diverse sesquiterpenoids and polyketides from a sponge-associated fungus Aspergillus sydowii SCSIO41301.

Five new compounds, including one bisabolane-type sesquiterpenoids, namely aspergillusene D (1), two new xanthones (2 and 3), and two new catecholderivatives (4 and 5), together with fourteen known compounds (6-19), were isolated and identified from the fungus Aspergillus sydowiiSCSIO 41,301 from the sponge Phakellia fusca. Their structures and absolute configurations were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. Most of the isolated compounds (1-3, and 6-19) were evaluated for their antiviral, cytotoxic, and antibacterial activities. Among them, new compounds 2 and 3 displayed obvious selective inhibitory activities against two influenza A virus subtypes, including A/Puerto Rico/8/34 (H1N1) and A/FM-1/1/47 (H1N1), with IC50 values ranging from 2.17 ± 1.39 to 4.70 ± 1.11 μM.