Transepithelial Transport of Ferulic Acid by Monocarboxylic Acid Transporter in Caco-2 Cell Monolayers

Abstract

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 in a vectorical way in the apical-basolateral direction. The permeation of ferulic acid was concentration-dependent and saturable; the Michaelis constant was 16.2 mM and the maximum velocity was 220.4 nmol min-1 (mg protein)-1. Various substrates for MCTs, such as benzoic acid and acetic acid, strongly inhibited the permeation of ferulic acid, demonstrating that ferulic acid is obviously transported by MCT. Antioxidative phenolic acid compounds from dietary sources like ferulic acid would be recognized and transported by MCT by intestinal absorption.

Transport oftrans-tiliroside (kaempferol-3-β-D-(6″-p-coumaroyl-glucopyranoside) and related flavonoids across Caco-2 cells, as a model of absorption and metabolism in the small intestine

“…p-Coumaric acid was found to have a significant apical to basolateral transfer (37%) of p-coumaric acid, and a lower basolateral efflux (12%), which is consistent with previously published work (Konishi and Shimizu, 2003;Konishi and Kobayashi, 2004;Poquet et al, 2008). p-Coumaric acid is hydrophilic (Log P -0.65 (Luo et al, 2011)) and has a relatively low molecular weight (164).…”

“…The degree of phenolic acid transport is associated with the extent of ionisation (Poquet et al, 2008); ionisation creates a concentration gradient across the intestinal cells allowing passive diffusion of the phenolic acid. It has also been proposed that facilitated transport of coumaric acid using a proton pump, which is only active across a concentration gradient (Konishi and Shimizu, 2003;Konishi and Kobayashi, 2004).…”

Non-Involvement of the Human Monocarboxylic Acid Transporter 1 (MCT1) in the Transport of Phenolic Acid

“…The cells were seeded at a density of 1 Â 10 5 /cm 2 and grown in Transwell inserts with a semipermeable membrane coated with type I collagen, as previously reported. [4][5][6][7][8]12,13) The integrity of the cell layer was evaluated by measuring the transepithelial electrical resistance (TER) with Millicell-ERS equipment (Millipore, Billerica, MA, USA). A monolayer with a TER value of more than 300 Ácm 2 was used for the transepithelial transport experiments.…”

“…The amount of p-coumaric or salicylic acid in this extract was estimated by using HPLC-ECD equipment fitted with an ESA coulometric detection system (ESA, Boston, MA, USA) as described in previous studies. [4][5][6][7][8]12,13) In brief, to measure p-coumaric acid, chromatographic separation was performed in a C18 column (ODS150, MC Medical, Tokyo, Japan) with mobile phase A (solvent A) of 50 mM sodium acetate containing 5% methanol (pH 3.0) and mobile phase B (solvent B) of 50 mM sodium acetate containing 40% acetonitrile and 20% methanol (pH 3.5). Eight electrode detector potentials (from 0 to 700 mV in increments of 100 mV) were used.…”

“…MCT-mediated absorption, partial MCT-mediated absorption, paracellular diffusion, and transcellular passive diffusion). [4][5][6][7][8] We have also established that the absorption characteristics of these compounds in the Caco-2 cell line are correlated with their absorption efficiency and bioavailability in vivo. [9][10][11] Furthermore, the microbial metabolites of poorly absorbed parent polyphenols are also thought to be absorbed and distributed by MCT, in a similar way to phenolic acids.…”