Nitric Oxide Inhibitory Meroterpenoids from the Fungus Penicillium purpurogenum MHZ 111

Five new meroterpenoids, purpurogenolides A–E (1–5), and four known metabolites (6–9) were isolated from the solid substrate fermentation cultures of the fungus Penicillium purpurogenum MHz 111. The structures of the new meroterpenoids were elucidated by analysis of spectroscopic and spectrometric data (1D and 2D NMR, IR, and HRESIMS). The absolute configurations of 1 and 5 were determined by single-crystal X-ray crystallographic analysis, and those of 2–4 were elucidated on the basis of experimental and calculated electronic circular dichroism spectra. Compounds 2–4 and 6 showed inhibition of nitric oxide production in lipopolysaccharide-activated BV-2 microglial cells with IC50 values of 0.8–30.0 μM.