The efflux of flavonoids morin, isorhamnetin-3-O-rutinoside and diosmetin-7-O-beta-D-xylopyranosyl-(1-6) -beta-D-glucopyranoside in the human intestinal cell line caco-2.
OBJECTIVE
In this study, we chose three of the flavonoids isorhamnetin-3-O-rutinoside(IRR) diosmetin-7-O-beta-D-xylopyranosyl-(1-6)-beta-D-glucopyranoside(DXG) and morin, which showed obvious efflux, to test the hypothesis that a specific efflux transporter is responsible for their transportation.


METHODS
The intestinal epithelial membrane transport of the flavonoids were examined using the monolayer of the human Caco-2 cell line grown in Transwells, a common model of intestinal absorption. The flavonoids were measured by high performance liquid chromatography with UV detector.


RESULTS
The efflux of morin, IRR and DXG, across Caco-2 cell monolayers was examined over the concentration range from 2 to 200 microM and showed a saturable process. The depletion of the cellular ATP stores with 5 mM iodoacetamide led to a significant inhibition of the efflux. Fifty micromolar verapamil, a chemical inhibitor of P-glycoprotein, had no effect on the transport of the three flavonoids, while the presence of 50 microM MK-571 and 1 mM probenecid, MRP inhibitors, resulted in an obvious reduction in the efflux. Moreover, inhibition of morin transport by MK-571 demonstrated concentration dependence. The transportation of the three flavonoids was compared with apigenin.


CONCLUSIONS
These data support a role for MRPs in the intestinal transcellular efflux of morin, IRR, DXG and possibly other hydrophilic flavonoid aglycons and glycosides.
Tian
Xiaojuan
X
Department of Chemical Biology and State Key laboratories of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100083, People's Republic of China.
Yang
Xiaoda
X
Wang
Kui
K
Yang
Xiuwei
X
D000255:Adenosine Triphosphate / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D001693:Biological Transport, Active; D018938:Caco-2 Cells; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007460:Iodoacetamide / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D011794:Quercetin / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D047309:Flavones
D000255:Adenosine Triphosphate; D000975:Antioxidants; D004187:Disaccharides; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007460:Iodoacetamide; D011339:Probenecid; D011422:Propionates; D011794:Quercetin; D011804:Quinolines; D014700:Verapamil; C515816:diosmetin-7-O-xylopyranosyl-1-6-glucopyranoside; C515815:isorhamnetin 3-O-rutinoside; C059141:verlukast; C008548:morin; D047309:Flavones; C039602:diosmetin