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Both chlorogenic and caffeic acids exhibited nonsaturable transport in Caco-2 cells, whereas caffeic acid also showed proton-coupled polarized absorption. Thus, the absorption efficiency of caffeic acid was greater than that of chlorogenic acid. Polarized transport of caffeic acid was inhibited by substrates of MCT such as benzoic and acetic acids. Almost(More)
Fluorescein is a marker-dye customary applied to the evaluation of tight-junctional permeability of epithelial cell monolayers. However, the true mechanism for the permeation has not been elucidated. Transepithelial transport of fluorescein in Caco-2 cell monolayers was therefore examined. Fluorescein transport was dependent on pH, and in a vectorical way(More)
Phenolic acids such as p-coumaric acid and microbial metabolites of poorly absorbed polyphenols are absorbed by the monocarboxylic acid transporter (MCT)-mediated transport system which is identical to the fluorescein/H(+) cotransport system. We focus here on the physiological impact of MCT-mediated absorption and distribution. We examined whether MCT1, the(More)
Our previous study (Biosci. Biotechnol. Biochem., 66, 2449-2457 (2002)), suggested that ferulic acid was transported via a monocarboxylic acid transporter (MCT). Transepithelial transport of ferulic acid was examined in this study by directly measuring the rate of its transport across Caco-2 cell monolayers. Ferulic acid transport was dependent on pH, and(More)
OBJECTIVES We recently reported that flavanone aglycones (hesperetin, naringenin and eriodictyol) are efficiently absorbed via proton-coupled active transport, in addition to transcellular passive diffusion, in Caco-2 cells. Here, we aimed to evaluate in detail the absorption mechanisms of these flavanones, as well as homoeriodictyol and sakuranetin. (More)
The intestinal absorption characteristics of phenolic acids (PAs) have been elucidated in terms of their affinity for the monocarboxylic acid transporter (MCT). Recently, the involvement of the stomach has been implicated in the absorption of polyphenols. The present work demonstrates that the gastric absorption efficiency of each PA is apparently different(More)
The absorption characteristics of rosmarinic acid (RA) were examined by measuring permeation across Caco-2 cell monolayers using an HPLC-electrochemical detector (ECD) fitted with a coulometric detection system. RA exhibited nonsaturable transport even at 30 mM, and the permeation at 5 mM in the apical-to-basolateral direction, J(ap-->bl), was 0.13(More)
m-Hydroxyphenylacetic acid (mHPA), 3,4-dihydroxyphenylacetic acid (DHPA), and 4-hydroxy-3-methoxyphenylacetic acid (HMPA) are major microbial metabolites of quercetin. After administration of quercetin to human subjects, these metabolites are readily detected in blood and urine. mHPA, DHPA, and HMPA are thought to exert protective biological activity within(More)
The cell permeability of hesperetin and hesperidin, anti-allergic compounds from citrus fruits, was measured using Caco-2 monolayers. In the presence of a proton gradient, hesperetin permeated cells in the apical-to-basolateral direction at the rate (Jap-->bl) of 10.43+/-0.78 nmol/min/mg protein, which was more than 400-fold higher than that of hesperidin(More)
The transepithelial transport of such common dietary phenolic acids as p-coumaric acid (CA) and gallic acid (GA) across Caco-2 cell monolayers was examined. CA transport was dependent on pH, and in a vectorial manner in the apical-basolateral direction. The permeation was concentration-dependent and saturable, the Michaelis constant and maximum velocity(More)