Gut Microbiota Modulation and Anti-Inflammatory Properties of Dietary Polyphenols in IBD: New and Consolidated Perspectives

Background: Polyphenols represent a great variety of compounds occurring in fruits, vegetables and plant-derived products. Dietary polyphenols have been found displaying several biological properties, such as anti-inflammatory, antioxidant and anti-aging activities, cardiovascular and neuro-protection, and reduction of the risk of intestinal diseases. The bio-efficacy of polyphenols is tightly linked to their bioavailability, to structural complexity and composition of food matrix in which they are present. Since most of the polyphenols are naturally stored in food matrices as glycosylated and/or variously decorated forms, they need an intestinal bio-conversion in more absorbable forms. Recent findings are highlighting the polyphenols-gut microbiota interplay in the health benefits linked to these compounds. Furthermore, the prebiotic-like activities of polyphenols on microbiota and their potential use in preventive/therapeutic strategies for gastrointestinal disorders are recently emerging. Conclusions: In this review, we will focus on the dietary flavonols, anthocyanins and stilbenes, as widely occurring polyphenols in human diet, their metabolism mediated by gut microbiota and their protective effects on inflammatory bowel diseases (IBDs).