New Polyaromatic Metabolites from a Marine-Derived Fungus Penicillium sp.

Herqueiazole (1), herqueioxazole (2), and herqueidiketal (3), polyaromatic metabolites with a novel skeletal class, were isolated from the marine-derived fungus Penicillium sp. Based on the combined spectroscopic analyses, the structures of 1 and 2 were determined to be the first examples of pyrrole- and oxazole-containing phenalenone compounds, respectively, whereas 3 possessed a novel skeleton with a highly oxidized naphthoquinone moiety. Compound 3 exhibited moderate cytotoxicity and significant inhibitory activity against sortase A.