Inhibition Mechanism of Catechins on Dietary AGEs Absorption and Toxicity

Dr. Qian Wu, from Hubei University of Technology, China, will join us this year to present a talk entitled “Inhibition Mechanism of Catechins on Dietary AGEs Absorption and Toxicity”.

In her study, using a simulated gastrointestinal digestion model, Dr. Wu showed that catechin efficiently inhibited the digestion of oligopeptide-AGEs. A mass-spectrometry- (MS) based proteomics approach (Q Exactive) was applied to identify the digestion products of glycated bovine serum albumin (BSA), and three oligopeptide-AGEs was found, including FWGK(160)-CML, LSQK(245)FPK-CML, WSVAR(221)LG-H1. No free AGEs were detected indicated that the digested glycated protein existed in the form of oligopeptide-AGEs. Addition of catechin as inhibitor, a significant decline in the fluorescence intensity of glycated protein, the degree of hydrolysis and free amino acids were observed and the particle size of the digestion products increased, which could indicate the inhibitory effects of catechin on the release of AGEs during gastrointestinal digestion.

Using Caco-2 cell model, we found that catechins could effectively inhibit the absorption of oligopeptide-AGEs and the expression of oligopeptide-transportor (PEPT1) and tight junction protein (ZO-1). The expression of ZO-1 in Caco-2 cells could be determined by immunohistochemical staining, and the results suggested that adding catechin could significantly increase the expression of ZO-1 (P< 0.05). Caco-2 cells were induced with BSA-AGEs digests for 24 h, and it was indicated that 20 µm and 50 µm catechins could reduce the expression of PepT1 by 53.8% and 73.1%, respectively (P< 0.01). In addition, molecular docking method was used to compare the binding ability of catechin to three oligopeptides-AGES (FWGK(160)-CML, LSQK(245)FPK-CML, WSVAR(221)L-G-H1) and PepT1, and it was found that catechin was easier to bind to PepT1. Therefore, the transport capacity of PepT1 to oligopeptide-AGEs was decreased.

It was found that the activation of RAGE receptor in rat liver were inhibited and the liver damage caused by dietary AGEs were reduced by catechin in rat model. SPF Rats were divided into four groups: normal diet (N), high-dose AGEs diet (H), 0.2% catechin supplemented diet (0.2%) and 0.5% catechin supplemented diet (0.5%), respectively. The expressions of RAGE, p38MAPK and NF-κB in the liver of the rats were detected by immunochemistry staining. The results showed that the activation of RAGE-p38MAPK-NF-κB signaling pathway was significantly inhibited by 0.5% catechin (p＜0.01).The expressions of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) genes in liver were detected by RT-PCR, and the results showed that the expression of inflammatory cytokines could be significantly decreased by 0.2% and 0.5% catechin.

Join us in Polyphenols Applications 2022 and benefit from the experience of professional researchers like Dr. Wu.

Polyphenols Applications 2022 Congress
September 28-30, 2022 - Valencia, Spain
www.polyphenols-site.com