Biological Activity and Therapeutic Potential of Quercetin for Inflammatory Bowel Disease

Rates of inflammatory bowel disease (IBD) are increasing globally. IBD is an idiopathic chronic inflammatory disorder of the gastrointestinal tract characterized by acute disease flares and remission. IBD has a multifactorial pathogenesis whereby environmental and genetic factors contribute to disease onset. IBD is a serious clinical disorder that significantly impairs the patient’s quality of life, and is associated with increased morbidity, mortality, and cancer risk. IBD is characterized by the loss of tolerance to luminal antigens resulting in a persistent and excessive immune response. There is currently an unmet need for novel treatment options for patients with IBD. In recent years, flavonoids, a class of polyphenols widely distributed in fruits and vegetables gained significant interest as potential therapeutic agents for inflammatory disorders including IBD. Many flavonoids regulate cellular transcription factors critical in antioxidant and antiinflammatory pathways within the innate and adaptive immune response. Among these flavonoids, quercetin and its related glycosides have demonstrated remarkable effects capable of attenuating inflammation in experimental models of IBD. To date, many mechanisms underlying quercetin’s biological activity have been elucidated; wherein quercetin is reported to downregulate NFκB, MAPK, STAT and AP-1, and upregulate Nrf2. Thus, the aim of the review is to present the evidence surrounding quercetins biological activity, and its potential as a novel dietary intervention for IBD.