red yeast rice contains monacolins , sterols , isoflavin as well as mono unsaturated fatty acids. Monacolins are naturally occurring inhibitors of 3-Hydroxy 3-Methyl Glutaryl CoA (HMG CoA) reductase , the key enzyme in cholesterol synthesis. The anti-Atherogenic effect of rice bran oil is due to modulating enzymes and genes involved in lipid metabolism inclding ATP Binding Cassette protein A1 , ApoA1 and Peroxisome Proliferator-activated Receptor 25. Its antioxidant effect is due to the upregulation of gene PON1 gene , which codes for the enzyme paraoxonase 1 , and increases its blood levels