LAUSR

Marine microorganisms have been evidenced as prolific sources of structurally intriguing secondary metabolites (SMs) with pharmaceutical potential; meanwhile, microbial chemistry will dominate future marine natural products research. Among them, the fungi of the common genus Penicillium are important producers of various SMs with interesting biological activities and novel structures including alkaloids, terpenes, polyketides, and lipopeptides. Naphthopyranones (1H‐naphtho‐[2,3‐c] pyran‐1‐one) encompass a linear tricyclic skeleton embedding naphthalene and fused δ‐lactone (α‐pyrone) rings, widely encountered in fungi, bacteria, lichen, and plants of polyketide biosynthetic origin. They have been found with a broad range of bioactivities, as exemplified by antimicrobial, cytotoxic, immunoregulatory, and antioxidant activity, arousing considerable interest from both synthetic and biosynthetic chemists. During the course of our search for novel bioactive SMs from marine fungi, a series of structurally diverse and biologically significant SMs have been obtained. The sponge‐associated fungus Penicillium sp. XWS02F62 was selected for chemical investigation due to its intriguing high‐performance liquid chromatography‐ultraviolet (HPLC‐UV) profiles of crude extracts based on solid rice medium, which resulted in the characterization of a new naphthopyranone (1), along with nine known polyketides (2−8) and sesquiterpenes (9−10). The structure including absolute configuration of 1 were unambiguously determined by extensive spectroscopic data interpretation, single‐crystal X‐ray diffraction analysis, and electronic circular dichroism (ECD) calculations. Herein, the isolation and structural elucidation, as well as cytotoxic evaluation of these compounds, are described in detail.