Heterocycles and a Sorbicillinoid from the Coral-Derived Fungus Penicillium chrysogenum

A detailed chemical study of the culture of a coral-derived fungus <i>Penicillium chrysogenum</i> resulted in the isolation and identification of four new aromatic heterocycles chrysoquinazolinones A-B (<b>1</b>-<b>2</b>) and chrysobenzothiazoles A-B (<b>3</b>-<b>4</b>), along with a new sorbicillinoid 4-carboxylsorbicillin (<b>5</b>). Chrysoquinazolinones A-B (<b>1</b>-<b>2</b>) combine a quinazolinone fragment with a bicyclo[2.2.2]octane or a pyrrolidone moiety, respectively, demonstrating the unexpected structures of marine natural products. Chrysobenzothiazoles A-B (<b>3</b>-<b>4</b>) possess a benzothiazole system and are the second isolation of this class of skeleton compounds from marine organisms. The existence of the pair of enantiomers (±<b>3</b>) was deduced by chiral HPLC analysis. Their structures and absolute configurations were elucidated by detailed spectroscopic analysis, comparison with the literature data, single-crystal X-ray crystallographic analysis and TDDFT-ECD calculations. Compound <b>5</b> exhibited moderate cytotoxicity against K562 and NCI-H446 cell lines, with IC₅₀ values of 15.00 μM and 16.87 μM, respectively.