Green/Roasted Coffee and Silverskin Extracts Inhibit Sugar Absorption by Human Intestinal Epithelial (Caco-2) Cells by Decreasing GLUT2 Gene Expression

Abstract

Moderate coffee ingestion has been associated with a decrease in type 2 diabetes risk, mainly due to its richness in chlorogenic acids (CGA). To explore this, extracts of green beans, roasted beans, and silverskin were prepared by aqueous ultrasound-assisted extraction and characterized by a reversed-phase high-performance liquid chromatography-photodiode array detector (RP-HPLC-DAD). The effects on the uptake of glucose and fructose by human intestinal epithelial (Caco-2) cells and the influence on the expression of sugar transporter genes (by RT-qPCR) were investigated and compared. The uptake of 3H-deoxy-D-glucose and 14C-fructose by Caco-2 cells was significantly reduced by all the extracts, with green coffee (which also contained higher amounts of CGA) achieving the highest efficiency. Although silverskin presented the lowest amounts of CGA and caffeine, it promoted an inhibitory effect similar to the effects of green/roasted beans. In the case of glucose uptake, the effect was even higher than for roasted coffee. This activity is explained by the ability of the extracts to markedly decrease GLUT2, but not GLUT5 gene expression. In addition, a decrease in SGLT1 gene expression was also found for all extracts, although not at a statistically significant rate for silverskin. This study also revealed a synergistic inhibitory effect of caffeine and 5-CQA on the uptake of sugars. Thus, silverskin appears as an interesting alternative to coffee, since the valorization of this by-product also contributes to the sustainability of the coffee chain.

Chlorogenic acid: a review on its mechanisms of anti-inflammation, disease treatment, and related delivery systems

“…Concurrently, research has illuminated chlorogenic acid's potential in enhancing metabolic parameters in hepatic and cardiac contexts, serving as a bulwark against obesity, cardiovascular maladies, and diabetes (Zhu et al, 2019;Zhang and Xu, 2022;Simona et al, 2023). In the realms of obesity and diabetes, chlorogenic acid has been identified to impede sugar absorption by human intestinal epithelial cells (Caco-2) via the modulation of Glut gene expression (Barreto et al, 2022). Additionally, it augments postprandial glycemic regulation, glucagon-like peptide-1 (GLP-1) response, and insulin sensitivity in normative populations (Aya et al, 2022;Zang et al, 2022).…”