Three new constituents from the fungus of Monascus purpureus and their anti-inflammatory activity

A chemical study on the EtOAc-soluble fraction of the 95% EtOH extract of red yeast rice fermented with the fungus Monascus purpureus BCRC 38110 (Eurotiaceae) has resulted in the isolation of three new compounds, i.e., two new 5',6'-dihydrospiro [isochromane-1,2'-pyran]-4'(3'H)-one derivatives, designated as monascuspirolide A (1) and monascuspirolide B (2) and one benzenoid derivative, monapurpureusin B (3), together with three known compounds, monaspurpurone (4), monascin (5), and ankaflavin (6). The structures and relative configurations of these compounds were elucidated by spectroscopic analyses, including 1D- and 2D-NMR spectroscopy and mass spectrometry, and by comparison of their spectral data with the literature data of authentic samples. To the best of our knowledge, the former two new compounds (1 & 2) displayed an unusual 5',6'dihydrospiro[isochromane-1,2'-pyran]-4'(3'H)-one pattern compared to previous Monascus metabolites. Some phytochemicals were evaluated for anti-inflammatory activity through the measurement of nitric oxide (NO) production levels in lipopolysaccharide (LPS)-stimulated murine-derived macrophages RAW264.7 cell lines.