Neuroprotective effects of quercetin: From chemistry to medicine

Neurodegenerative diseases are the leading cause of disability in the elderly. Growing evidence suggests that oxidative stress, which is associated with aging, is the basis of most neurodegenerative disorders; and polyphenols, acting as antioxidant agents, reduce the risk of neurodegenerative diseases. Quercetin is a flavonoid occurring in many plant foods commonly consumed as part of a regular diet. It shows a number of biological properties connected to its antioxidant activity. This review assesses the molecular structure of quercetin, its food sources and bioavailability. Moreover, the main results obtained from in vitro studies, observing the mechanisms of action through which quercetin exerts its antioxidant activity, are reported. However, most of these effects have only been observed in vitro and clinical studies are lacking.