Three nitrogen-containing metabolites from an algicolous isolate of Trichoderma asperellum

As one of the most productive species,Trichoderma asperellum,especially isolated from marine algae,has contributed a number of new terpenes and nitrogen-bearing compounds,encouraging our continuous efforts to further explore them.Consequently,three new nitrogen-containing secondary metabolites,including cyclo(L-5-MeO-Pro-L-5-MeO-Pro)(1),5'-acetoxy-deoxycyclonerin B(2),and 5'-acetoxy-deoxycyclonerin D(3)were isolated from the marine alga-derived endophytic fungus Trichoderma asperellum A-YMD-9-2.Their structures and relative configurations were fully elucidated through spectroscopic techniques,mainly including 1D/2D NMR and MS.The absolute configurations of 1 and 2 were ascertained on the basis of X-ray diffraction(Cu Kα radiation)and ECD data,respectively.The isolation of these new nitrogen-bearing compounds adds to the structural diversity of marine algicolous Trichoderma spp.,and they display potent inhibition against some marine phytoplankton species.