Antioxidant activity of pigments derived from Monascus purpureus-fermented rice, corn, and sorghum.

A mixture of pigments derived from Monascus has been shown to possess antioxidant activity, but specific pigments responsible for the activity have not been identified yet. This is the first investigation on the contribution of Monascus pigment compounds to the antioxidant activity. This research focused on the antioxidant activity of Monascus pigments (MP) produced by a solid state fermentation with rice, corn, whole sorghum grain (WSG), dehulled sorghum grain (DSG) and sorghum bran (SB) substrates. The antioxidant activity of the pigments was evaluated in vitro by 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity method. The profile and compounds of pigments were analyzed by using thin layer chromatography and liquid chromatography coupled with tandem mass spectrometry, respectively. These results showed that DPPH-scavenging activities of MP were in a range of 588 and 2,950 µmol Trolox Equivalent (TE)/100g. Rice-MP showed the highest DPPH-scavenging activity, followed by DSG-MP, WSG-MP, SB-MP and Corn-MP, while no DPPH-scavenging activity was detected in a commercial Beni Koji pigments. The higher amount of pigments was found to have the higher antioxidant activity. Pearson correlation analysis of the scavenging activity of DPPH and the amount of individual pigment showed that 2 compounds those are Monapilol B and rubropunctamine have a high correlation with the r value of 0.973 and 0.968, respectively. It was estimated that Monapilol B possesses higher contribution (64%) to the DPPH scavenging activity than that of Rubropunctamine (33%). [ABSTRACT FROM AUTHOR]