Transepithelial transport of 6-O-caffeoylsophorose across Caco-2 cell monolayers

The aim of this study was to clarify the transport behaviour and mechanism of caffeic acid analogue bearing a sugar-moiety, 6-O-caffeoylsophorose (CS), in Caco-2 cells. The absorption of CS was investigated by its transport across Caco-2 cell monolayers using a high-performance liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS). The permeation of CS was concentration-dependent and reached the plateau at >6 mM. The apparent permeability (P(app)) of CS in the apical-to-basolateral direction was 5.4×10(-7) cm/s, while in the reversed direction the P(app) value was significantly reduced (1.9×10(-7) cm/s). CS transport was competitively inhibited by phloretin, an inhibitor of monocarboxylic acid transporter (MCT). Benzoic acid, an MCT substrate, also reduced CS transport. A less significant change of CS transport was observed across Caco-2 cell monolayers pretreated with quercetin, a suppressor of tight-junction. These findings strongly indicate that CS, a caffeic acid analogue bearing sophorose moiety, can be transported across Caco-2 cell monolayers via the MCT pathway.