An Update on the Cardiovascular Effects of Quercetin, a Plant Flavonoid

Quercetin, a widely occurring plant flavonoid, is well-known for its antioxidant activity. A great deal of research in the form of animal and cell culture studies has been performed over the last 30 years, as well as a few clinical studies in human populations; however, its specific effects on various contributing factors to cardiovascular disease are not fully understood. This review seeks to summarize many of the latest studies regarding the effects of quercetin on cardiovascular health. Overall, the research reflects positive effects of quercetin on atherosclerosis, hypertension, dyslipidemia and endothelial function. However, in vivo studies have shown that quercetin imparts varying plasma levels due to its poor aqueous solubility and low stability in biological fluids. Research efforts are currently being devoted to overcome these limitations by designing and testing modified forms of quercetin or improved formulations which provide enhanced bioavailability and higher efficacy. The development of improved dosage forms for in vivo administration of quercetin and well-designed clinical studies are warranted for further evaluation of the effects of quercetin on cardiovascular health.