Quercetin glucosides inhibit glucose uptake into brush-border-membrane vesicles of porcine jejunum.
Recent experimental data point to an interaction of dietary flavonol monoglucosides with the intestinal Na-dependent glucose transporter 1 (SGLT1). To investigate this interaction in more detail, we performed experiments with SGLT1-containing brush-border-membrane vesicles (BBMV) from pig jejunum. The flavonol quercetin-3-O-glucoside (Q3G) concentration-dependently inhibited Na-dependent uptake of radioactively labelled d-glucose into BBMV. Uptake of l-leucine was not inhibited by Q3G, indicating a specific interaction of the glucoside with SGLT1. Whereas the maximal transport rate of concentration-dependent initial glucose uptake was not altered in the presence of Q3G, the constant for half-maximal glucose uptake was increased, suggesting a competitive type of inhibition of glucose uptake by Q3G. Trans-stimulation experiments suggested the transport of Q3G via SGLT1. In addition, Q3G decreased the Na-independent diffusive uptake of glucose into BBMV. Other flavonoids were also tested for their inhibitory effect on d-glucose uptake. Among the tested quercetin glycosides, only the 4'-O-glucoside (Q4G) also inhibited Na-dependent glucose uptake into BBMV, whereas the 3-O-galactoside, the 3-O-glucorhamnoside and the aglycone quercetin itself were ineffective. Glucosides of some other flavonoid classes such as naringenin-7-O-glucoside, genistein-7-O-glucoside and cyanidin-3,5-O-diglucoside were ineffective as well. Thus, dietary quercetin monoglucosides, for example, Q3G and Q4G, have an impact on intestinal nutrient transporters such as SGLT1 and related systems.
Cermak
Rainer
R
Institute of Animal Nutrition, Physiology and Metabolism, Christian-Albrechts-University Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
Landgraf
Sandra
S
Wolffram
Siegfried
S
D000818:Animals; D001692:Biological Transport; D004032:Diet; D005947:Glucose / Q000493:pharmacokinetics*; D005960:Glucosides / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008871:Microvilli / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000378:metabolism*; D051269:Sodium-Glucose Transporter 1; D013552:Swine
D005960:Glucosides; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; C016527:isoquercitrin; C021304:hyperoside; D011794:Quercetin; D007930:Leucine; D005947:Glucose; C080613:spiraeoside