[Research progress on therapeutic potential of quercetin]

Quercetin is a naturally occurring phytochemical with good bioactivity, which mainly exists in the form of glycoside in vegetables, fruits, tea, and wine and exhibits beneficial health effects. Quercetin is a dietary polyphenol that exerts the protective effects through diet or use as a food supplement. Compared with chemical agents, quercetin is widely available and safe. Quercetin has been extensively studied for its anti-diabetic, anti-hypertensive, anti-Alzheimer's disease, anti-arthritic, anti-influenza virus, anti-microbial infection, anti-aging, autophagy-regulating, and cardiovascular protective effects. Studies on its activities against different can-cer cell lines have also been reported recently. However, the poor water solubility, rapid in vivo metabolism, and short half-life of quercetin have led to its low bioavailability, thus limiting its application in the field of medicine. Quercetin nanoparticles and nanoparticle drug delivery system have been effectively utilized for enhancing its bioavailability. This paper reviewed the therapeutic potential of quercetin from both preclinical and clinical aspects and proposed solutions to improve its bioavailability, so as to provide a reference for the therapeutic application of natural compounds in the field of medicine.