Background-It is well established that glutamine supplemented elemental diets result in less severe intestinal damage in experimental colitis. However, few studies have examined the mode of action of glutamine in reducing intestinal damage. Aims-To examine the eVects of glutamine supplemented elemental diets on the potent inflammatory cytokines interleukin 8 (IL-8) and tumour necrosis factor (TNF-) in trinitrobenzene sulphonic acid (TNBS) induced colitis which presents with both acute and chronic features of ulcerative colitis. Methods-Sprague-Dawley rats were randomised into three dietary groups and fed 20% casein (controls), or 20% casein supplemented with either 2% glutamine (2% Gln) or 4% glutamine (4% Gln). After two weeks they received intracolonic TNBS to induce colitis. Results-Both Gln groups of rats gained more weight than the control group (p<0.05) which had progressive weight loss. Colon weight, macroscopic, and microscopic damage scores for the Gln groups were lower than in the control group (p<0.05). IL-8 and TNF-concentrations in inflamed colonic tissues were lower in the Gln groups than in the control group (p<0.05), and correlated well with disease severity. Bacterial translocation was lower both in incidence (p<0.05) and in the number of colony forming units (p<0.05) for the Gln groups, than in the control group. With respect to all indices studied, the 4% Gln group performed better than did the 2% Gln group. Conclusion-Prophylactic glutamine supplementation modulates the inflammatory activities of IL-8 and TNF-in TNBS induced colitis.

Quercetin and quercetin glycosides from food or dietary supplements appear in body tissues almost exclusively as glucuronated, sulfated, and methylated quercetin conjugates, suggesting that the in vivo bioactivity of quercetin may be due to its metabolites. In this study, pre- and postabsorptive metabolism of orally ingested quercetin was examined by comparing the metabolite pattern in gastrointestinal (GI) tissues, contents, and internal tissues. F344 rats (n = 6) were fed for 6 wk a diet containing 0.45% quercetin and the metabolite patterns were determined in the tissues and contents of stomach, small intestine, cecum, and colon and in liver, kidney, and plasma using LC-MS/MS. GI contents contained predominantly unmetabolized quercetin at 94-100%, whereas quercetin in GI tissues was present as 11 different sulfated, glucuronated, and methylated metabolites at 32% in stomach, 88% in small intestine, 27% in cecum, and 46% in colon. Quercetin was further metabolized postabsorption and found in liver, kidney, and plasma almost exclusively as sulfated methyl-quercetin glucuronide. The unique pattern of quercetin metabolites in each GI tissue indicates extensive biotransformation before absorption and distribution in rats.

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