A new pyrrole derivative from the extracts of the fungus monascus pilosus-fermented rice.

A chemical study on the n-BuOH-soluble fraction of the 95% EtOH extract of red yeast rice fermented with the fungus Monascus pilosus BCRC 38093 (Eurotiaceae) has resulted in the isolation of one new natural pyrrole derivative, designated as monascuspyrrole (1) together with nine known compounds, 3β-hydroxystigmast-5-en-7-one (2), β-sitostenone (3), monascin (4), ankaflavin (5), N-trans-feruloyltyramine (6), N-cis-feruloyltyramine (7), vanillic acid (8), methyl paraben (9), and syringaldehyde (10). The structure of the new compound 1 was identified by 1D and 2D NMR spectroscopy, as well as by high-resolution mass spectrometry. Other known compounds were identified by comparison of their spectral data with the literature data of authentic samples. Compounds 1 and 4 displayed mild inhibitory effect of nitric oxide production. Among the nine known isolates, compounds 2, 3, 6, and 7 were found for the first time in this species.