Antioxidant properties of methanolic extracts from monascal rice

Fungus Monascus (Monascaceae) possesses functional components effective in improving human health. The fungus was inoculated into rice and a traditional product (Monascus-fermented rice, anka, red koji) was produced after the colonization of fungal mycelia. Our objective was to evaluate the antioxidant properties of methanolic extracts from inoculated rice products [monascal polished rice (MPR) and monascal dehulled rice (MDR)] as compared to uninoculated rice products [polished rice (PR) and dehulled rice (DR)]. With regard to EC50 values (mg extract/ml) of methanolic extracts, inhibitions of peroxidation were excellent and in the descending order of PR>DR>MDR>MPR. Effectiveness in reducing powers was in the descending order of MPR⪢MDR⪢DR>PR. Scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl radicals were in the descending order of MPR>MDR>PR∼DR. Chelating abilities on ferrous ions were in the descending order of MPR∼MDR>PR>DR. Total phenols were the major naturally occurring antioxidant components found. Overall, monascal rice products were better in reducing power, scavenging and chelating abilities and higher in total phenol content than uninoculated rice products.