Antioxidant Properties of Red Yeast Rice (Monascus purpureus) Extracts
2012
Kwon, C.S., Andong National University, Andong, Republic of Korea
Red yeast rice (RER) has been used in China for centuries for its medicinal properties and is an increasingly popular alternative lipid-lowering treatment. This study was carried out to estimate the antioxidant properties of RER extracts. The ethyl acetate extract exhibited the DPPH radical scavenging activity of 85% at 0.2 mg/mL and IC∧50 0.13 mg/mL. A significant proportion of hydroxyl radicals in a cuvette were scavenged: 44.2% at 2.5 ㎍/mL, 74.1% at 5.0 ㎍/mL, and greater than 100% at 10 ㎍/mL. The HepG₂ cells pre-treated with RER ethyl acetate extract reduced the hydroxyl radicals significantly compared to the control cells. Oxidative DNA damage was measured using a Comet assay. The RER ethyl acetate extract did not induce any DNA damage per se, and appeared to enhance the resistance to DNA damage caused by an oxidant challenge with H₂O₂, whereas lovastatin increased the level of DNA damage in the cells in both the unstressed (no oxidant) and those stressed with H₂O₂. The relative gene expression of the antioxidant enzymes in HepG₂ cells were also affected by the RER ethyl acetate extract. The HepG₂ cells were pre-incubated with the RER ethyl acetate extract, and then stressed with H₂O₂ or left unstressed (no oxidant). In the unstressed cells, superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase (GPx) were increased significantly 3.25-fold and 2.67-fold, respectively, whereas in the stressed cells, the catalase (CAT) level was increased by 4.64-fold and 7.0-fold at 5 ㎍/mL and 10 ㎍/mL, respectively, compared to those of the control. From these results, RER appears to be effective in suppressing oxidative stress.
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