PRODUCTION AND IDENTIFICATION OF N-GLUCOSYLRUBROPUNCTAMINE AND N-GLUCOSYLMONASCORUBRAMINE FROM MONASCUS RUBER AND OCCURRENCE OF ELECTRON DONOR-ACCEPTOR COMPLEXES IN THESE RED PIGMENTS

The filamentous fungus Monascus ruber produces water-soluble red pigme nts in a submerged culture when grown in a chemically defined medium c ontaining glucose as a carbon source and monosodium glutamate as a nit rogen source, Two new molecules with polyketide structures, N-glucosyl rubropunctamine and N-glucosylmonascorubramine, constituting under som e conditions 10% of the total extracellular coloring matter when gluco se as a carbon source was in excess (20 g/liter), were isolated and st ructurally characterized by high-pressure liquid chromatography, Dione x methods, H-1 and C-13 nuclear magnetic resonance spectroscopy, and m ass spectrometry, The occurrence of the electron donor-acceptor comple x effect was demonstrated by UV spectroscopy, polarography, and thin-l ayer voltammetry, The use of n-butanol as an extraction solvent stabil ized the pigments against the effects of daylight for several months, promoting the stability of this type of complex.