Effect of Hydrolyzable Tannins on Glucose-Transporter Expression and Their Bioavailability in Pig Small-Intestinal 3D Cell Model

• Main Authors: Maksimiljan Brus, Robert Frangež, Mario Gorenjak, Petra Kotnik, Željko Knez, Dejan Škorjanc
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Molecules
• Subjects: hydrolyzable tannin; glucose; glucose transporters; porcine epithelial cell line; tannin bioavailability; glucose transport
• Online Access: https://www.mdpi.com/1420-3049/26/2/345

Intestinal transepithelial transport of glucose is mediated by glucose transporters, and affects postprandial blood-glucose levels. This study investigates the effect of wood extracts rich in hydrolyzable tannins (HTs) that originated from sweet chestnut (<i>Castanea sativa</i> Mill.) and oak (<i>Quercus petraea</i>) on the expression of glucose transporter genes and the uptake of glucose and HT constituents in a 3D porcine-small-intestine epithelial-cell model. The viability of epithelial cells CLAB and PSI exposed to different HTs was determined using alamarBlue^®. qPCR was used to analyze the gene expression of SGLT1, GLUT2, GLUT4, and POLR2A. Glucose uptake was confirmed by assay, and LC–MS/ MS was used for the analysis of HT bioavailability. HTs at 37 µg/mL were found to adversely affect cell viability and downregulate POLR2A expression. HT from wood extract Tanex at concentrations of 4 µg/mL upregulated the expression of GLUT2, as well as glucose uptake at 1 µg/mL. The time-dependent passage of gallic acid through enterocytes was influenced by all wood extracts compared to gallic acid itself as a control. These results suggest that HTs could modulate glucose uptake and gallic acid passage in the 3D cell model.