Screening of Azaphilone Derivatives From Monascus pilosus-Fermented Rice (Red Yeast Rice) and Their Evaluation as Nonsteroidal Androgen Receptor Antagonists

Abstract

Monascus pilosus BCRC 38093 is a mutant strain of M. pilosus BCRC 38072. The 95% ethanol extract of red yeast rice fermented by M. pilosus BCRC 38093 showed 4 major signals on high performance liquid chromatography (HPLC) examination. The extraction of metabolites and chromatography of the ethyl acetate crude extract on silica gel yielded 2 azaphilone derivatives, monascin (1) and monascinol (2), and 2 monacolin-type derivatives, acid-form monacolin K (3) and lactone-form monacolin K (4). Their structural characterization was elucidated by spectroscopic techniques ultraviolet-visible (UV), infrared spectroscopy (IR), and two dimensional-nuclear magnetic resonance (2D-NMR) and mass spectrometry. These compounds were assayed for their anti-androgen activity; monascinol (2) exhibited strong activity.