Quercetin‐3‐rhamnoglucoside (rutin) stimulates transport of organic anion compounds mediated by organic anion transporting polypeptide 2B1

Quercetin‐3‐rhamnoglucoside (rutin) has a wide spectrum of biochemical and pharmacological activities. Rutin is absorbed mainly in its unmetabolized form. Organic anion transporting polypeptide (OATP) 2B1 is a major uptake transporter in the intestine. Thus, it is important for the prevention of adverse events to understand drug interactions mediated by OATP2B1 in the absorption process. This study assessed the effect of rutin on transport by OATP2B1. Rutin stimulated the uptake of estrone‐3‐sulfate (E‐3‐S), taurocholic acid (TCA), cholic acid (CA) and rosuvastatin by OATP2B1, but not p‐coumaric acid or ferulic acid. The EC50 of rutin for transport by OATP2B1 was 2.32 μm. The Km value of E‐3‐S for OATP2B1 in the presence of rutin (9.21 μm) was almost the same as that in the absence of rutin (8.53 μm). On the other hand, the Vmax of E‐3‐S transport by OATP2B1 in the presence of rutin (270 pmol/mg protein/min) was 1.2‐fold higher than that in the absence of rutin (218 pmol/mg protein/min). Moreover, the expression level of OATP2B1 on the cell membrane was increased by treatment with rutin for 5 min without alteration of the total OATP2B1 expression level. Moreover, the increase in the localization of OATP2B1 at the cell surface was detected by the immunocytochemistry. The stimulatory effect of rutin is a little weak but may affect the absorption of OATP2B1 substrates, because rutin is taken daily in foods and its intestinal concentration would reach the stimulatory range of OATP2B1. Copyright © 2014 John Wiley & Sons, Ltd.