The roles of flavonoids in the treatment of inflammatory bowel disease and extraintestinal manifestations: A review

Inflammatory bowel disease (IBD) is a complex and chronic inflammatory disorder mainly affecting the intestine. However, IBD can present in a variety of extraintestinal manifestations (EIMs), which increase the risk of morbidity and mortality. The incidence of IBD has rapidly increased worldwide, imposing a marked global burden of disease. Natural products such as flavonoids have attached attention due to their bioactivity and safety. In this review, we focus on elucidating the key mechanisms through which flavonoids exert their antioxidant, anti-inflammatory, immunoregulatory, and gut microbiota stabilizing effects in treating IBD, while emphasizing their protective role in maintaining the intestinal epithelial barrier and gut-vascular barrier. Antiviral properties, as well as modulation of enteroendocrine system for prevention and treatment of IBD have also been discussed. Importantly, flavonoids may also play a potential role in the development of intestinal fibrosis and EIMs associated with IBD.