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Theaflavins (TFs) are derived from black tea, an important source of dietary polyphenols. Although the potential interactions between dietary polyphenols and drugs have been demonstrated through in vitro and in vivo studies, little information is available concerning the influence of TFs on drug disposition. Organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in human enterocytes and plays a role in the intestinal absorption of numerous drugs. The current study evaluated the effects of black tea extracts on the pharmacokinetics of rosuvastatin in rats, and investigated the effect of four major TFs (theaflavin, theaflavin-3-gallate, theaflavin-3′-gallate and theaflavin-3,3′-digallate) on the transport activity of OATP2B1. Black tea extracts significantly decreased the maximum plasma concentration (C max ) and area under the plasma concentration-time curve (AUC 0 -8 ) of rosuvastatin by 48% and 37%, respectively (p < 0.001 and p < 0.01, respectively).Moreover, OATP2B1-mediated rosuvastatin and estrone-3-sulfate uptake was significantly reduced in the presence of TFs. A kinetic study revealed that the uptake efficiency (in terms of V max /K m ) of rosuvastatin was decreased following treatment with TFs. Black tea extracts also reduced OATP2B1-mediated rosuvastatin uptake.These results suggest that black tea reduces the plasma concentrations of rosuvastatin by inhibiting the intestinal OATP2B1-mediated transport of rosuvastatin.

Loxoprofen, a propionate non-steroidal anti-inflammatory drug (NSAID), is used widely in East Asian countries. However, little is known about the transport mechanisms contributing to its intestinal absorption. The objectives of this study were to characterize the intestinal transport of loxoprofen using the human intestinal Caco-2 cell model. The transport of loxoprofen was investigated in cellular uptake studies. The uptake of loxoprofen into Caco-2 cells was pH- and concentration-dependent, and was described by a Michaelis-Menten equation with passive diffusion (K : 4.8 mm, V : 142 nmol/mg protein/30 s, and K : 2.2 μl/mg protein/30 s). Moreover, the uptake of loxoprofen was inhibited by a typical monocarboxylate transporter (MCT) inhibitor as well as by various monocarboxylates. The uptake of [ C] l-lactic acid, a typical MCT substrate, in Caco-2 cells was saturable with relatively high affinity for MCT. Because loxoprofen inhibited the uptake of [ C] l-lactic acid in a noncompetitive manner, it was unlikely that loxoprofen uptake was mediated by high-affinity MCT(s). Our results suggest that transport of loxoprofen in Caco-2 cells is, at least in part, mediated by a proton-dependent transport system. Copyright © 2016 John Wiley & Sons, Ltd.

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