Polyphenolic flavonoids inhibit macrophage-mediated oxidation of LDL and attenuate atherogenesis

Macrophage-mediated oxidation of LDL, a hallmark in early atherosclerosis, depends on the oxidative state of the LDL, and that of the macrophages. The LDL oxidative state is determined by the balance between the LDL polyunsaturated fatty acids and cholesterol, which are prone to oxidation, and the LDL associated antioxidants. Dietary consumption of nutrients rich in polyphenols, such as red wine or liquorice results in LDL enrichment with these polyphenolic flavonoids, and hence, subsequent LDL oxidation is reduced. In addition, enrichment of LDL with polyphenols results in a marked decrease in the susceptibility of the lipoprotein to aggregation (another lipoprotein atherogenic modification). The oxidative status of the macrophages depends on the balance between cellular oxygenases and antioxidants. Macrophage enrichment with polyphenolic flavonoids in vitro or in vivo also reduce macrophage oxidative state, and subsequently cell-mediated oxidation of LDL. The present review article summarizes our current data on these aspects of the antiatherogenic potential of polyphenolic flavonoids.