Anti-inflammatory activities of alkaloids from the mangrove endophytic fungus Phomopsis sp. SYSUQYP-23

Five new maleimide derivatives, (+)- and (-)- farinomalein F (1), (+)- and (-)- farinomalein G (2), farinomalein H (3) and one new linearly fused prenylated indole alkaloid phomoamide (8), along with five known compounds 4-7 and 9 were isolated from the mangrove endophytic fungus Phomopsis sp. SYSUQYP-23. Their structures and absolute configurations were determined by HRESIMS, spectroscopic and electronic circular dichroism (ECD) calculations. Bioassay results showed that compounds 3-9 exhibited significant inhibitory activities against nitric oxide (NO) production in lipopolysaccharides (LPS) induced RAW 264.7 cells, with IC50 values ranging from 4.5 to 25 μM. Moreover, the molecular docking study implied the probable binding interaction of compounds 4 and 5 with nitric oxide synthase.