Isoflavonoid glucosides are deconjugated and absorbed in the small intestine of human subjects with ileostomies

Abstract

Background:Although soy isoflavonoids have a number of healthpromoting benefits, information concerning the sites of their absorption and metabolism in humans remains limited. Isoflavonoid absorption from the gut requires deconjugation of glucosides to aglycones. Objective: The objective was to investigate the role of the small intestine in isoflavonoid absorption and metabolism in humans. Design: Human subjects with fully functional gastrointestinal tracts (n ҃ 6) and ileostomy subjects (n ҃ 6) were fed a single soy meal containing 64.8 mg isoflavonoid aglycone equivalents (95% as glucosides). Metabolism of isoflavonoids in the upper gastrointestinal tract was examined by analyzing ileal effluent from ileostomy subjects, and absorption was assessed indirectly by quantifying isoflavonoids and several metabolites in 24-h urine pools. Results: Chyme contained 36.7% of ingested isoflavonoid aglycone equivalents, primarily (95.8%) as aglycones. Qualitative profiles (x Ȁ SEM) of isoflavonoid excretion in urine (daidzein glycitein genistein) and the quantity of isoflavonoid equivalents were not significantly different between the control (18.4 Ȁ 2.2 mg) and ileostomy (13.5 Ȁ 3.2 mg) subjects. Dihydrodaidzein was present in the urine of all subjects, although the amount excreted by ileostomy subjects was less than that excreted by the control subjects. The percentage of producers and mean quantities of dihydrogenistein, equol, and O-desmethylangolensin in the urine of ileostomy subjects also were lower than those of control subjects. Conclusions: Ileostomy subjects efficiently deglycosylate isoflavonoid glucosides in the small intestine and appear to absorb aglycones with an efficiency comparable with that of control subjects. However, the production of microbial metabolites of isoflavonoids is limited in ileostomy subjects.Am J Clin Nutr 2007;85: 1050 -6.

Gastrointestinal absorption and metabolism of soy isoflavonoids in ileal‐canulated swine

“…We also have observed extensive small intestinal hydrolysis of IFN glucosides in human subjects with ileostomies [30]. Similarly, Walle et al [32] found that ingested quercetin glucosides were completely hydrolyzed to aglycones prior to absorption in human subjects with ileostomies.…”

“…IFN and their metabolites were extracted from swine urine as previously described with slight modifications [29,30]. Aliquots of urine samples collected during the 24 h period before feeding the first test diet and 0 -24 and 24 -48 h after each test diet were separately analyzed to measure IFN equivalents excreted daily by each pig.…”

SGLT-1 Transport and Deglycosylation inside Intestinal Cells Are Key Steps in the Absorption and Disposition of Calycosin-7-O- -D-Glucoside in Rats

“…Absorption and metabolism of soy isoflavonoid glucosides have been extensively studied in recent years to elucidate their physiologic functions (Walsh et al, 2007;Islam et al, 2014). Deglycosylation by lactase-phloridzin hydrolase (LPH), an enterocyte-specific enzyme localized to the brush-border membrane in small intestine, is a critical step in the absorption and metabolism of isoflavonoid glucosides.…”

“…Deglycosylation by lactase-phloridzin hydrolase (LPH), an enterocyte-specific enzyme localized to the brush-border membrane in small intestine, is a critical step in the absorption and metabolism of isoflavonoid glucosides. This process generates aglycones that can enter enterocytes through passive diffusion (Day et al, 2000;Walsh et al, 2007). After cellular accumulation, aglycones undergo extensive metabolism in enterocytes (Chen et al, 2005).…”

Inhibition of hydroxycinnamic acid sulfation by flavonoids and their conjugated metabolites

“…Hence, the inhibitory activities of these quercetin conjugates could be greater in the liver in vivo. The elimination half lives of quercetin metabolites in human studies were in the range of [10][11][12][13][14][15][16][17][18][19][20] hours. The relatively long half-lives of the quercetin conjugates imply that consumption of quercetin-rich foods can potentially inhibit hydroxycinnamic acid metabolism in vivo over a significant period of time (~1 day) [24].…”