Trichocarotins A–H and trichocadinin A, nine sesquiterpenes from the marine-alga-epiphytic fungus Trichoderma virens

Nine new sesquiterpenes, involving carotane and cadinane derivatives, were discovered from the fungus Trichoderma virens Y13-3, an algal epiphyte. [Display omitted] •Nine new sesquiterpenes were characterised from Trichoderma virens Y13-3.•They represent two rarely occurring sesquiterpene types from filamentous fungi.•Six of the isolates exhibited potent inhibition against some marine plankton species. In addition to CAF-603, 14-hydroxy CAF-603 (trichocarane B), 7-β-hydroxy CAF-603, and trichocarane A, eight new carotane sesquiterpenes, trichocarotins A–H, and one new cadinane sesquiterpene, trichocadinin A, were isolated from the culture of Trichoderma virens Y13-3, obtained from the surface of a marine red alga. Their structures and relative configurations were unambiguously assigned by interpretation of 1D/2D NMR and MS data, and their absolute configurations were established by X-ray diffraction or ECD spectra aided by quantum chemical calculations. These compounds represent two rarely occurring sesquiterpene types from filamentous fungi, and six of them feature potent inhibition against some marine plankton species.