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Three new meroterpenoids, asperaustins A–C (1–3), and seven known analogues (4–10) were isolated from a marine-derived Aspergillussp. fungus. The structures and absolute configurations of these new compounds were unequivocally determined by extensive spectroscopic analyses and single-crystal X-ray diffraction analyses. Asperaustin A (1) possesses an unusual spiro[4.5]deca-3,6-dien-2-one moiety with a unique 5/6/6/6/5 pentacyclic skeleton. The absolute configurations of austinoneol A (7) and precalidodehydroaustin (9) were determined by single-crystal X-ray diffraction analyses using Cu Kα radiation for the first time.

A chemical investigation of the secondary metabolites of a marine-derived Aspergillussp. led to the isolation and characterization of 13 phenolic compounds, including 10 new compounds (1–10). Seven new compounds (1–7) are unusual phenolic C-glycosides, while the other new compounds (8–10) are structurally related aglycones. The chemical structures of these new compounds were elucidated by 1D and 2D NMR and HRESIMS spectroscopic analyses. The absolute configurations of these new C-glycosides were determined by comparison of experimental electronic circular dichroism spectra with those of calculated ones. In addition, the anti-inflammatory activities of these compounds were evaluated, and compound 9significantly inhibited nitric oxide production with an IC50value of 6.0 ± 0.5 μM in lipopolysaccharide-induced RAW264.7 cells. Moreover, compound 9also showed anti-inflammatory activity by inhibiting the NF-κB-activated pathway.