Two new tricycloalternarene esters from an alga-epiphytic isolate of Alternaria alternata.

Two new tricycloalternarene-type meroterpenes, 17-O-methyltricycloalternarene D (1) and methyl nortricycloalternarate (4), and two known congeners, TCA D (2) and TCA 1b (3), were isolated from the culture of a marine red alga-epiphytic fungal strain (k21-1) of Alternaria alternata. The planar structures and relative configurations of these two new compounds were unequivocally identified by a combination of 1D/2D NMR, UV, IR, and mass spectra and by comparison with literature data, and the absolute configurations were assigned by analysis of ECD spectra. Compounds 1-4 were evaluated for growth inhibition of four marine plankton species, but they appeared weak or moderate to inhibit them.

Trichocitrin, a new fusicoccane diterpene from the marine brown alga-endophytic fungus Trichoderma citrinoviride cf-27.

One new diterpene, trichocitrin (1), and four known secondary metabolites, nafuredin (2), 5-hydroxy-2,3-dimethyl-7-methoxychromone (3), 24-methylenecycloartanol (4) and citrostadienol (5), were isolated from the culture of marine brown alga-endophytic Trichoderma citrinoviride cf-27. Trichocitrin (1) represents the first Trichoderma-derived and furan-bearing fusicoccane diterpene, and its structure and relative configuration were identified by analysis of 1D/2D NMR and mass spectroscopic data. Compounds 1 and 2 exhibited 8.