THE INHIBITION BY QUERCETIN AND GANHUANGENIN ON OXIDATIVELY MODIFIED LOW-DENSITY-LIPOPROTEIN

Oxidatively modified low-density lipoproteins (ox-LDL) have been stron gly implicated in the pathogenesis of atherosclerosis, Both in vivo an d in vitro experiments have shown that antioxidant treatment can atten uate oxidative damage from LDL, The aim of this study was to establish whether the ox-LDL induced by in vitro incubation can be inhibited by two well-known natural antioxidants, quercetin and ganhuangenin. Ln o ur study, oxidation was quantitatively assessed in the presence and ab sence of these antioxidants by measuring lipid oxidation products and lipid peroxide generation. When non-oxidized, native LDL was incubated in the presence of 20 mM Cu2+, LDL modifications were found to procee d in a time-dependent manner. Our results further showed both querceti n and ganhuangenin inhibited the oxidative modification of LDL, as evi denced by the reduced thiobarbituric acid reactive substances (TBARS), phosphatidylcholine hydroperoxides (PCOOH) production, and ox-LDL flu orescence intensity. Based on these data, we concluded that both querc etin and ganhuangenin have the ability to effectively suppress in vitr o LDL oxidation, thereby providing additional evidence for their poten tial beneficial use as antiatherogenic agents. (C) 1998 John Wiley & S ons, Ltd.