Harziane and cadinane terpenoids from the alga-endophytic fungus Trichoderma asperellum A-YMD-9-2.

• Three new terpenoids (2 – 4) were obtained from Trichoderma asperellum A-YMD-9-2. • Isolate 2 may be an intermediate in the biosynthesis of harziandione from harzianone. • Isolates 3 and 4 represent the second occurrence of cadinanes in Trichoderma. In addition to the known harziandione (1), one new diterpenoid, 3 S -hydroxyharzianone (2), and two new sesquiterpenoids, 4-cadinen-11,12-diol (3) and 4-cadinen-11,13-diol (4), were isolated from the culture of Trichoderma asperellum A-YMD-9-2, an endophytic fungal strain from the marine red alga Gracilaria verrucosa. The structures and relative configurations of new isolates were established by analysis of spectroscopic techniques, including 1D/2D NMR, IR, and MS, and their absolute configurations, except for those at C-11 of 3 and 4 , were assigned by comparison of the ECD curve or specific optical rotation data with those of analogues. Compound 2 may be an intermediate in the biosynthesis of harziandione from harzianone, while 3 and 4 represent the second occurrence of cadinane sesquiterpenoids in Trichoderma. Compounds 2 − 4 exhibited potent inhibition of several marine phytoplankton species. [ABSTRACT FROM AUTHOR]