The small intestinal mucosa acts as a rutin reservoir to extend flavonoid anti-inflammatory activity in experimental ileitis and colitis

•Rutin but not quercetin has anti-inflammatory activity in experimental colitis.•Rutin is active in both ileal and colonic inflammation•Rutin advantage is protracted exposure of the inflamed segment to the flavonoid.•Rutin is a candidate functional food in the management of idiopathic inflammation of the intestine. Flavonoids are considered versatile components in many functional foods with multiple health benefits. One of the most abundant flavonoids, rutin, is effective in experimental colitis, which is attributed to colonic intraluminal release of its flavonol quercetin. Surprisingly, however, quercetin is ineffective. We aimed to explore whether rutin/quercetin protect against trinitrobenzenesulphonic acid (TNBS) experimental ileitis. TNBS colitis was also studied for reference. Rutin was active in ileitis and in colitis, while quercetin showed only marginal effects. In order to explain this discrepancy we measured flavonoid mucosal levels and found that anti-inflammatory activity correlated with the presence of rutin in the ileal mucosa rather than with colonic mucosal levels of rutin or quercetin. In fact, rutin was protective against colitis even when administered intraperitoneally. Our results indicate that rutin is taken up by the ileal mucosa and slowly released to the lumen, resulting in extended exposure of the mucosa to quercetin.