Bioactive metabolites and botanical preparations from plants used as medicines and foods in ulcerative colitis: a mechanism-oriented narrative review of multi-target regulation

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease with a complex pathophysiology involving immune dysregulation, gut microbiota dysbiosis, intestinal barrier impairment, oxidative stress, and regulated cell death. Current therapeutic strategies, including 5-aminosalicylic acid, corticosteroids, immunosuppressants, biologics, and small-molecule agents, have improved disease management; however, incomplete or lost response, adverse effects, and the need for long-term treatment remain important clinical challenges. Bioactive metabolites and botanical preparations from medicinal and food plants have gained increasing attention because of their diverse pharmacological activities and potential to modulate multiple pathological processes involved in UC. This mechanism-oriented narrative review critically summarizes recent evidence on the effects of these plant-derived metabolites, botanical preparations, and combination strategies in UC using a framework that links major UC pathological modules to molecular targets/pathways and functional outcomes, with particular emphasis on anti-inflammatory and antioxidant actions, regulation of ferroptosis and pyroptosis, modulation of autophagy and endoplasmic reticulum stress, protection of the intestinal barrier, and regulation of gut microbiota. The reported mechanisms recurrently converge on signaling networks involving NF-κB, MAPK, Nrf2/ARE, and PI3K/Akt. Evidence from isolated-metabolite cellular studies, extract- and preparation-level studies, animal models, and available human studies varies by the study type. We interpret it according to its mechanistic and translational relevance. Although the available literature indicates that these metabolites may regulate interconnected UC-related pathways through multi-target actions, most mechanistic evidence remains preclinical. Important limitations include incomplete reporting of dose ranges, controls, sample sizes, and quantitative effect estimates; inconsistent documentation of taxonomic authentication and extract characterization; limited metabolite-specific pharmacokinetic and bioavailability data; insufficient translational validation of advanced delivery strategies; variability in microbiota-related findings among experimental models; and limited clinical validation. Further well-designed pharmacological and clinical studies are required to clarify the most robust mechanisms and identify plant-derived metabolites with the greatest potential for further development in UC.