Asperochones A and B, two antimicrobial aromatic polyketides from the endophytic fungus Aspergillus sp. MMC-2

Two novel fungal metabolites, asperochones A and B, were obtained from an Aspergillus sp. Their structures were determined by 1D/2D nuclear magnetic resonance (NMR) spectroscopy, high resolution electrospray ionization mass spectroscopy (HRESIMS), and single-crystal X-ray diffraction analysis. Asperochone A possesses an intriguing skeleton bearing 5/6/6/6/7/5/5/5 octacyclic ring system, and asperochone B also exhibits an unusual carbon skeleton with five stereochiral centers. Their structures were proposed as heterotrimeric and heterodimeric products of aromatic polyketides. In addition, asperochone A exhibited a potential anti-tuberculosis effect since it showed a moderate potency against Mycobacterium smegmatis.