Highly oxygenated acorane sesquiterpenes from the marine-sourced Trichoderma harzianum CS-152

Three new highly oxygenated acorane sesquiterpenes, namely, 9,10-epoxidicacoren-2,7,8-triol (1), 8S-acoren-2,7,8-triol (2), and 8R-acoren-2,7,8-triol (3), along with four known analogs (4-7), were isolated from the deep-sea derived fungus Trichoderma harzianum CS-152. Except for compound 7, the other compounds lack conjugation and do not exhibit fluorescence under UV light at 254 nm, which posed a challenge in their detection and required careful monitoring during separation. The isolation and purification of these compounds was achieved using traditional silica gel column chromatography. Their chemical structures and relative configurations were elucidated by comprehensive analysis of 1D/2D NMR, HRESIMS, and their absolute configurations were determined by modified Mosher's method. Compounds 1 and 4 displayed inhibitory activities against the aquatic pathogen Aeromonas hydrophila, each with a MIC value 4 μg/mL, while compound 7 showed antibacterial activity against Pseudomonas aeruginosa with a MIC value 4 μg/mL.