New Polyketides from Mangrove Endophytic Fungus Penicillium sp. BJR-P2 and Their Anti-Inflammatory Activity

Four new polyketide compounds, including two new unique isocoumarins penicillol A (1) and penicillol B (2) featuring with spiroketal rings, two new citreoviridin derivatives citreoviridin H (3) and citreoviridin I (4), along with four known analogues were isolated from the mangrove endophytic fungus Penicillium sp. BJR-P2. Their structures were elucidated by extensive spectroscopic methods. The absolute configurations of compounds 1-4 based on electronic circular dichroism (ECD) calculations, DP4+ analysis, and single-crystal X-ray diffraction are presented. All the new compounds were evaluated for anti-inflammatory activity. An anti-inflammatory assay indicated that compound 2 inhibited lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells, with half-maximal inhibitory concentration (IC50) values of 12 mu M, being more potent than the positive control, indomethacin (IC50 = 35.8 +/- 5.7 mu M). Docking study showed that compound 2 was perfectly docking into the active site of murine inducible nitric oxide oxygenase (iNOS) via forming multiple typical hydrogen bonds.

Automated summary

Four new polyketide compounds and two new citreoviridin derivatives were isolated from the mangrove endophytic fungus Penicillium sp. BJR-P2. Compound 2 exhibited stronger anti-inflammatory activity by inhibiting NO production induced by LPS.