Eremophilane- and Acorane-Type Sesquiterpenes from the Deep-Sea Cold-Seep-Derived Fungus Furcasterigmium furcatum CS-280 Cultured in the Presence of Autoclaved Pseudomonas aeruginosa QDIO-4

Six new sesquiterpenes, including four eremophilane derivatives fureremophilanes A-D (<b>1</b>-<b>4</b>) and two acorane analogues furacoranes A and B (<b>5</b> and <b>6</b>), were characterized from the culture extract of the cold-seep derived fungus <i>Furcasterigmium furcatum</i> CS-280 co-cultured with autoclaved <i>Pseudomonas aeruginosa</i> QDIO-4. All the six compounds were highly oxygenated especially <b>2</b> and <b>3</b> with infrequent epoxyethane and tetrahydrofuran ring systems. The structures of <b>1</b>-<b>6</b> were established on the basis of detailed interpretation of 1D and 2D NMR and MS data. Their relative and absolute configurations were assigned by a combination of NOESY and single crystal X-ray crystallographic analysis, and by time-dependent density functional (TDDFT) ECD calculations as well. All compounds were tested the anti-inflammatory activity against human COX-2 protein, among which, compounds <b>2</b> and <b>3</b> displayed activities with IC₅₀ values 123.00 µM and 93.45 µM, respectively. The interaction mechanism was interpreted by molecular docking.