Seven new meroterpenoids from the fungus Penicillium sclerotiorum GZU-XW03–2

Seven previously undescribed meroterpenoids, peniscmeroterpenoids H − N (1–7), were isolated from the marine-derived fungus Penicillium sclerotiorum GZU-XW03–2. Their structures were established by the spectroscopic methods and the electronic circular dichroism (ECD) calculations. Peniscmeroterpenoid H was a 6/6/6/5/6 rearranged pentacyclic meroterpenoid, featuring a unique 2-oxaspiro[5.5] undeca-4,7-dien-3-one motif. Peniscmeroterpenoids I and J (2 and 3) owned rare 6(D)/5(E) fused rings were not common in natural products, and compound 2 was the second example of a berkeleyone analogue stripped of the methyl ester fragment. Peniscmeroterpenoid K (4) was the first case where the C-24 was oxidized. In bioassay, compound 5 showed moderate anti-inflammatory activity.