The aim of this study was to investigate the transporter-mediated transport of N-acetyl 5-aminosalicylic acid (Ac-5-ASA) and the effect of quercetin on Ac-5-ASA transport.

Caco-2 cell monolayers grown in Transwells were used to study the transport of Ac-5-ASA in the absence or presence of quercetin, and apical-to-basolateral and basolateral-to-apical apparent permeability (PappAB and PappBA values, respectively) was determined. The effect of transporter inhibitors, such as MK571, quinidine and mitoxantrone, on the transport of Ac-5-ASA was investigated.

In the absence of transporter mediators, the transport of Ac-5-ASA was much higher in the basolateral-to-apical direction than in the opposite direction. The PappBA/PappAB ratio of Ac-5-ASA was 4.89. Quercetin inhibited the apical efflux of Ac-5-ASA and decreased the PappBA/PappAB ratio to 1.05. Of the transporter inhibitors, MK571 decreased the PappBA/PappAB ratio to 1.07; however, neither quinidine nor mitoxantrone had an effect on Ac-5-ASA transport.

Ac-5-ASA was excreted by multidrug resistance-associated protein 2 from Caco-2 cells, and its transport was inhibited by quercetin. Our findings suggest that dose levels of sulfasalazine or 5-aminosalicylic acid can be decreased by coadministration of quercetin, leading to improved pharmaceutical care for inflammatory bowel diseases.

The aim of this study was to investigate the transporter-mediated transport of N-acetyl 5-aminosalicylic acid (Ac-5-ASA) and the effect of quercetin on Ac-5-ASA transport.

Caco-2 cell monolayers grown in Transwells were used to study the transport of Ac-5-ASA in the absence or presence of quercetin, and apical-to-basolateral and basolateral-to-apical apparent permeability (PappAB and PappBA values, respectively) was determined. The effect of transporter inhibitors, such as MK571, quinidine and mitoxantrone, on the transport of Ac-5-ASA was investigated.

In the absence of transporter mediators, the transport of Ac-5-ASA was much higher in the basolateral-to-apical direction than in the opposite direction. The PappBA/PappAB ratio of Ac-5-ASA was 4.89. Quercetin inhibited the apical efflux of Ac-5-ASA and decreased the PappBA/PappAB ratio to 1.05. Of the transporter inhibitors, MK571 decreased the PappBA/PappAB ratio to 1.07; however, neither quinidine nor mitoxantrone had an effect on Ac-5-ASA transport.

Ac-5-ASA was excreted by multidrug resistance-associated protein 2 from Caco-2 cells, and its transport was inhibited by quercetin. Our findings suggest that dose levels of sulfasalazine or 5-aminosalicylic acid can be decreased by coadministration of quercetin, leading to improved pharmaceutical care for inflammatory bowel diseases.