Dothideomins A-D, Antibacterial Polycyclic Bisanthraquinones from the Endophytic Fungus Dothideomycetes sp. BMC-101.

Four new bisanthraquinones, dothideomins A-D ( 1 - 4 ), were identified from Dothideomycetes sp. BMC-101, an endophytic fungus isolated from Magnolia grandiflor a L. leaves. Their chemical structures were established by NMR analysis, single-crystal X-ray crystallography, and ECD analysis. Dothideomins A-D ( 1 - 4 ) were characterized by an unusual 6/6/6/5/6/3/6/6 octocyclic scaffold ( 1 and 2 ) and a 6/6/6/5/6/6/6 heptacyclic scaffold ( 3 and 4 ), respectively. All compounds, especially 1 and 3 , exhibited potent antibacterial activity with MIC values ranging from 0.4 to 0.8 μg/mL.