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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #170039
Title: GASTROINTESTINAL TISSUES OF THE RAT METABOLIZE DIETARY QUERCETIN

Author
item GRAF, BRIGITTE - TUFTS/HNRCA
item MILBURY, PAUL - TUFTS/HNRCA
item AMEHO, CLEMENT - TUFTS/HNRCA
item LI, TING - TUFTS/HNRCA
item DOLNIKOWSKI, GREGORY - TUFTS/HNRCA
item BLUMBERG, JEFFREY - TUFTS/HNRCA

Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2004
Publication Date: 3/24/2004
Citation: Graf, B.A., Milbury, P.E., Ameho, C.K., Li, T., Dolnikowski, G.G., Blumberg, J.B. 2004. Gastrointestinal tissues of the rat metabolize dietary quercetin [abstract]. Experimental Biology 2004:Meeting Abstracts. p. A516.

Interpretive Summary:

Technical Abstract: To investigate the hypothesis that dietary quercetin is metabolized in the gastrointestinal (GI) tract before or during absorption, pooled stomach, small intestine, cecum and colon tissues and their respective lumen contents were analyzed from six F344 rats fed 0.5% quercetin for 6 wk. Homogenized samples were extracted with methanol/phosphate buffer and partitioned against ethyl acetate. The aqueous phase was purified by solid phase extraction, and then both phases were combined and concentrated. Using HPLC-UV and MS-MS, 14 quercetin conjugates with one or more methyl, sulfate or glucuronide moieties were identified. Less than 10% of quercetin in luminal contents and >65% in GI tissues were metabolized. Stomach tissue contained 2 sulfates and 2 glucuronated sulfates of quercetin while stomach contents showed no evidence of biotransformation. Metabolism was greatest in the small intestine and its luminal content where 95% and 9% of quercetin was metabolized, respectively. Small intestine contained principally monoglucuronides, while its contents held about equal amounts of monoglucuronides, di-glucuronides, and quercetin sulfates. Cecum and colon tissue contained 9 different quercetin conjugates, while their contents held only trace amounts of quercetin metabolites. These results indicate that GI tissue, especially small intestine, is a major site of quercetin metabolism in rats.