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

Abstract

Four new bisanthraquinones, dothideomins A–D (1–4), were identified from Dothideomycetes sp. BMC-101, an endophytic fungus isolated from Magnolia grandiflora 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.

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“…BMC-101 that is an endophyte of Magnolia grandiflora . 10 The authors propose that the biosynthetic pathway to cladoxanthone A 13 , a metabolite of a Cladosporium species, involves a Diels–Alder cycloaddition between an α-methylenecyclopentanone derivative and a xanthone precursor. 11 The structures of dothideomin A 12 and cladoxanthone A 13 were confirmed by X-ray analyses.…”