Combined Prebiotic Extract of Mung Bean, Red Bean, and Fennel Improves Intestinal Barrier Integrity in HT-29 Cells and DSS-Induced Colitis via Gut Microbiota Alteration

Inflammatory bowel disease (IBD) involves chronic inflammation and disruption of the intestinal barrier, often accompanied by alterations in gut microbiota composition. This study examined the protective potential of a prebiotic mixture extract (PME) prepared from <i>Vigna radiata</i> (mung bean), <i>Vigna angularis</i> (red bean), and <i>Foeniculum vulgare</i> (fennel) using the HT-29 cell and colitis animal model. PME exhibited concentration-dependent antioxidant activity, with greater radical-scavenging capacity in the ABTS assay than in the DPPH assay. In LPS-stimulated HT-29 epithelial cells, PME reduced the mRNA expression of inflammation-associated genes (TNF-α, IL-1β, NF-κB) and upregulated tight junction markers (CLDN1 and OCLN), demonstrating its anti-inflammatory and supportive effects on the intestinal barrier. Vitexin, a C-glycosylated flavonoid, was detected in PME and is expected to mediate these protective effects. In a DSS-induced colitis mouse model, PME administration alleviated disease severity by increasing colon length, reducing serum levels of inflammatory cytokines and COX-2/PGE2, and restoring intestinal permeability. Furthermore, PME modulated the gut microbiota by enhancing beneficial bacteria such as <i>Bifidobacterium</i> and <i>Faecalibaculum</i> while suppressing inflammation-associated taxa, including <i>Escherichia</i>, <i>Bacteroides</i>, and <i>Mucispirillum</i>. These improvements collectively suggest that PME reinforces epithelial barrier integrity and promotes intestinal homeostasis through both anti-inflammatory and microbiota-regulating actions.