| Abstract
| - Red yeast rice obtained as cultures of Monascus AS3.4444 on rice was extracted and analyzed by high-performance liquid chromatography (HPLC). Two new Monascus metabolites with similar fluorescence spectra (λex = 396 nm, λem = 460 nm) and UV absorption spectra (λmax = 386 nm) were detected. They were isolated by rechromatography on a silica gel column and semipreparative HPLC, and two strong blue fluorescent compounds were obtained. Their structures were elucidated by electrospray ionization mass spectrometry (ESI−MS), electrospray ionization tandem mass spectrometry (ESI−MS/MS), intensive ESI−MS, and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR, COSY, and HMBC) studies. High-resolution mass spectrometry indicated the molecular formulas C21H24O5 and C23H28O5. The two new compounds, named monasfluore A and monasfluore B, respectively, contain a alkyl side chain, γ-lactone, and propenyl group, whereas the more lipophilic compound, monasfluore B, is a higher homologue of monasfluore A, with the more lipophilic octanoyl instead of the hexanoyl side chain.
|
