Objective—
Animal and clinical studies have suggested that polyphenols in fruits, red wine, and tea may delay the development of atherosclerosis through their antioxidant and anti-inflammatory properties. We investigated whether individual dietary polyphenols representing different polyphenolic classes, namely quercetin (flavonol), (−)-epicatechin (flavan-3-ol), theaflavin (dimeric catechin), sesamin (lignan), or chlorogenic acid (phenolic acid), reduce atherosclerotic lesion formation in the apolipoprotein E (ApoE)
−/−
gene–knockout mouse.
Methods and Results—
Quercetin and theaflavin (64-mg/kg body mass daily) significantly attenuated atherosclerotic lesion size in the aortic sinus and thoracic aorta (
P
<0.05 versus ApoE
−/−
control mice). Quercetin significantly reduced aortic F
2
-isoprostane, vascular superoxide, vascular leukotriene B
4
, and plasma-sP-selectin concentrations; and augmented vascular endothelial NO synthase activity, heme oxygenase-1 protein, and urinary nitrate excretion (
P
<0.05 versus control ApoE
−/−
mice). Theaflavin showed similar, although less extensive, significant effects. Although (−)-epicatechin significantly reduced F
2
-isoprostane, superoxide, and endothelin-1 production (
P
<0.05 versus control ApoE
−/−
mice), it had no significant effect on lesion size. Sesamin and chlorogenic acid treatments exerted no significant effects. Quercetin, but not (−)-epicatechin, significantly increased the expression of heme oxygenase-1 protein in lesions versus ApoE
−/−
controls.
Conclusion—
Specific dietary polyphenols, in particular quercetin and theaflavin, may attenuate atherosclerosis in ApoE
−/−
gene–knockout mice by alleviating inflammation, improving NO bioavailability, and inducing heme oxygenase-1. These data suggest that the cardiovascular protection associated with diets rich in fruits, vegetables, and some beverages may in part be the result of flavonoids, such as quercetin.