Isolation and characterization of dihydromonacolin-MV from Monascus purpureus for antioxidant properties

The methanolic extract of Monascus purpureus cultivated by solid-state fermentation on rice showed strong 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and better yield as compared to other polarity based extracted fractions. It was selected for further purification of the antioxidant. The activity-guided repeated fractionation of methanolic extract on a silica gel column chromatography yielded a compound that exhibited strong antioxidant activity. Based on the spectroscopic analysis by UV, IR, 1H NMR, 13C NMR, 2D-HSQCT NMR, and MS, the antioxidant isolated was elucidated as a derivative of dihydromonacolin-K, where the ester group is 2-methyl propionate, designated as dihydromonacolin-MV. The DPPH radical was significantly scavenged by the dihydromonacolin-MV (IC50 20+/-1 microg ml-1). The dihydromonacolin-MV showed strong inhibition of lipid peroxidation in a liposome model with an IC50 value of 5.71+/-0.38 microg ml-1 and superoxide radical scavenging activity with an IC50 value of 163.97+/-2.68 microg ml-1.