Quercetin as a systemic chemopreventative agent: structural and functional mechanisms

There is a growing focus on diet and the use of naturally abundant compounds as supplements because their properties have many potential health benefits with minimal side effects. The flavonol-type flavonoid quercetin has increased in popularity because it is a highly studied, multidimensional bioactive compound that possesses both antioxidant properties and the ability to modulate signal transduction pathways. Direct antioxidant properties may play a role in the abrogation of both DNA damage, but potentially of more importance quercetin, can also target multiple signaling pathways associated with oncogenesis and tumor progression, which include DNA damage, inflammation and obesity. Quercetin can also upregulate proteins that abrogate free radical damage, such as p53. The concurrent targeting of quercetin's multiple bioactivities presents a potent chemopreventative strategy, but because bioavailability of quercetin is poor it will be necessary to develop quercetin analogs to maximize the full chemopreventative potential of the compound. This review will explore the structural and mechanistic properties of quercetin as they relate to its ability to act as a chemopreventative compound. A better understanding of quercetin's mechanistic properties could aid in the rational design of more potent or bioavailable flavonol-type compounds.