Abstract
Two new hydrogenated azaphilones (1 and 2), together with the known azaphilone (3) were isolated from the red soil-derived acid-tolerant fungus Penicillium purpureum OUCMDZ-019 by OSMAC (one strain many compounds) strategy. Their structures were determined by nuclear magnetic resonance (NMR) spectroscopy analysis and electronic circular dichroism (ECD) calculations. Compound 1 was the first reported azaphilone that salified with pyridine and chlorination occurred at C-1, and it exhibited potential inhibitory activity on melanin production as tyrosinase inhibitor in vivo. Furthermore, (+)-mitorubrinol acetate (3) showed significantly inhibitory activity against H1N1 with IC50 values of 58.6 μM (ribavirin, IC50 85.0 μM) as the first report.