Tannins as Therapeutic Agents for Ulcerative Colitis: Mechanisms and Prospects in Regulating Gut Inflammatory-Oxidative Homeostasis.

Ulcerative colitis (UC) is a multifactorial disease characterized by chronic intestinal inflammation and disrupted oxidative balance, significantly impairing patients' quality of life. Tannins, a class of polyphenolic compounds widely distributed in plants, have demonstrated notable therapeutic potential against UC due to their inherent antioxidant and anti-inflammatory properties. This study employs a systematic literature review of databases, including PubMed and Web of Science, to investigate the molecular mechanisms by which tannins restore intestinal inflammatory and oxidative homeostasis. The findings indicate that tannins directly scavenge reactive oxygen species (ROS) via their polyphenolic structure, mitigate oxidative damage, upregulate antioxidant enzyme expression, suppress pro-inflammatory cytokine secretion, and preserve intestinal barrier integrity. Despite their significant therapeutic promise, challenges such as low bioavailability and structural complexity remain. Future research should prioritize bioavailability enhancement, clarification of structure-activity relationships, and translational studies to facilitate the clinical application of tannin-based therapies for UC.