Discovery of sugarnitriles A and B, and structural reassignment of SF-2140, from a sugarcane endophytic actinomycete Amycolatopsis sp. JS-O27

Three rare cyano-substituted indole N -glycosides, SF-2140 ( 1 ) and its two previously undescribed derivatives, sugarnitriles A ( 2 ) and B ( 3 ), were isolated from a sugarcane endophytic actinomycete Amycolatopsis sp. JS-O27. The planar structures of 1 – 3 were established by HRESIMS data and detailed 1D/2D NMR spectroscopic analysis, and the conformations of the sugar moieties were deduced by the analysis of 3 J H-H coupling constants and NOESY data, and comparison of their electronic circular dichroism (ECD) spectra. Compounds 1 and 3 exhibited moderate to weak antibacterial activity against Escherichia coli at 100 μg/mL.