Harnessing the Anti-Inflammatory Properties of Polyphenols in the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) encompasses a spectrum of chronic inflammatory conditions affecting the gastrointestinal tract, notably ulcerative colitis (UC) and Crohn's disease (CD). Both UC and CD result from the interplay between genetic and environmental factors that trigger an exacerbated immune response against gut microorganisms, leading to non-resolving inflammatory damage in the mucosa of specific zones in the intestine. Despite extensive research, current treatments often entail invasive interventions with considerable adverse effects on patient well-being. Consequently, there is a pressing need to find alternative and complementary therapeutic strategies aimed at ameliorating chronic inflammation and restoring intestinal barrier integrity. Polyphenols are plant-based compounds formed naturally or as semi-synthetic/synthetic derivatives with proven health-promoting effects and translational applications in a broad spectrum of chronic diseases. Preclinical models of IBD largely support the efficacy of a broad variety of polyphenols due to their well-documented antioxidant and modulatory properties on the immune system and gut microbiota. Likewise, a growing number of studies using distinct types of polyphenols are being conducted in humans, although more efforts are still warranted. In the present review, the main polyphenols investigated in vitro and in vivo models of IBD will be summarized, as well as the available trials or observational data accessible in humans. Finally, the role of polyphenols in the clinical context of IBDs, along with the main problematics regarding their translational issues and concerns will be discussed, including bioavailability, their inclusion in healthy dietary patterns and foods, interaction with other drugs, and other important points to be addressed by future research.