Volume 91, Issue 6, June (2004), pp. 849-855 © The Author 2004
doi:10.1079/BJN20041128

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Quercetin glucosides inhibit glucose uptake into brush-border-membrane vesicles of porcine jejunum

Rainer Cermak¹, Sandra Landgraf¹ and Siegfried Wolffram^1
1Institute of Animal Nutrition, Physiology and Metabolism, Christian-Albrechts-University Kiel, Olshausenstrasse 40, D-24098 , Kiel, Germany<

 (Received 23 September 2003–Revised 15 January 2004–Accepted 13 February 2004)

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.

Keywords:
Flavonoids, Quercetin monoglucosides, Intestinal glucose transport, Sodium-dependent glucose transporter 1

Abbreviations:
BBM, brush-border membrane, BBMV, brush-border-membrane vesicles, LPH, lactase phloridzin hydrolase, Q3G, quercetin-3-O-glucoside, Q4G, quercetin-4′-O-glucoside, SGLT1, Na-dependent glucose transporter 1