Bioactive Polyhydroxanthones from .

Eight new polyhydroxanthones, penicixanthones A-H (-), including four monomers (-) and four dimers (-), were isolated from solid cultures of SC0070. Their structures were elucidated by extensive spectroscopic analysis, X-ray single-crystal diffraction, and theoretical computations of ECD spectra. Penicixanthone B () has a hexahydroxanthone structure featuring an unusual oxygen bridge between C-6 and C-8a. Penicixanthone D () is distinct from other penicixanthones in stereochemistry, and its biosynthetic mechanism was proposed based on theoretical simulations for the reaction pathway of C-10a epimerization. Penicixanthone G () exhibited the most potent cytotoxicity (IC: 0.3-0.6 μM) when tested against human carcinoma A549, HeLa, and HepG2 cells, whereas it was nontoxic to the normal Vero cells (IC > 50 μM). It also displayed the strongest antibacterial activity (MIC: 0.4 μg/mL) against both and the methicillin-resistant strain MRSA.