A new 2H-benzindazole compound from Alternaria alternata Shm-1, an endophytic fungus isolated from the fresh wild fruit of Phellinus igniarius.

Endophytic fungi have been shown in recent years to produce a series of bioactive secondary metabolites. Several endophytic fungi were isolated from the fresh wild body of Phellinus igniarius, and initially evaluated for their antimicrobial activity. Among which, Shm-1 extract showed moderate inhibitory activity against Clavibacter michiganense and the fungus was identified to be Alternaria alternata Shm-1 through the comparison of morphological characteristics and the sequence of the rDNA ITS with those of other Alternaria species. A new 2H-benzindazole derivative, alterindazolin A (1), has been isolated from cultures of the endophyte Alternaria alternata Shm-1. Its structure was characterized as 1-benzyl-5-p-hydroxy-phenyloxygen-benz[e]indazole by spectroscopic data analysis including 1D NMR, 2D NMR and MS spectrum.