A series of meroterpenoids with highly oxygenated skeletons from the endophytic fungus Penicillium sp. and their anti-inflammatory activities.

Four undescribed meroterpenoids, peniclactone D (1) and penichrodrimanins A-C (5-7), along with five known analogues (2-4, 8, and 9), were isolated from the fungus Penicillium sp. GDGJ-285. Their structures and absolute configurations were established on the basis of spectroscopic analyses and single-crystal X-ray diffraction. Compound 1 represents a highly oxygenated 6/5/6/5/5/5 polycyclic ring system, and 7 is a chrodrimanin-type meroterpenoid with a rare ether linkage between rings A and B via C-3 and C-9. Compound 5 exhibited notable inhibitory effect on nitric oxide (NO) production in LPS-induced RAW 264.7 cells, with the IC50 value of 18.50 ± 1.26 μM compared to dexamethasone (33.61 ± 4.45 μM). The further investigation indicated that 5 could suppress LPS-induced TNF-α, IL-1β, and iNOS expression via inhibition of NF-κB signaling pathway.