Selected Phytochemicals and Culinary Plant Extracts Inhibit Fructose Uptake in Caco-2 Cells

Abstract

Abstract:This study compared the ability of nine culinary plant extracts containing a wide array of phytochemicals to inhibit fructose uptake and then explored the involvement of intestinal fructose transporters and phytochemicals for selected samples. The chemical signature was characterized by high performance liquid chromatography with mass spectrometry. Inhibition of [ 14 C]-fructose uptake was tested by using human intestinal Caco-2 cells. Then, the relative contribution of the two apical-facing intestinal fructose transporters, GLUT2 and GLUT5, and the signature components for fructose uptake inhibition was confirmed in naive, phloretin-treated and forskolin-treated Caco-2 cells. HPLC/MS analysis of the chemical signature revealed that guava leaf contained quercetin and catechin, and turmeric contained curcumin, bisdemethoxycurcumin and dimethoxycurcumin. Similar inhibition of fructose uptake (by ~50%) was observed with guava leaf and turmeric in Caco-2 cells, but with a higher contribution of GLUT2 for turmeric and that of GLUT5 for guava leaf. The data suggested that, in turmeric, demethoxycurcumin specifically contributed to GLUT2-mediated fructose uptake inhibition, and curcumin did the same to GLUT5-mediated fructose uptake inhibition, but GLUT2 inhibition was more potent. By contrast, in guava leaf, catechin specifically contributed to GLUT5-mediated fructose uptake inhibition, and quercetin affected both GLUT5-and GLUT2-mediated fructose uptake inhibition, resulting in the higher contribution of GLUT5. These results suggest that demethoxycurcumin is an important contributor to GLUT2-mediated fructose uptake OPEN ACCESSMolecules 2015, 20 17394 inhibition for turmeric extract, and catechin is the same to GLUT5-mediated fructose uptake inhibition for guava leaf extract. Quercetin, curcumin and bisdemethoxycurcumin contributed to both GLUT5-and GLUT2-mediated fructose uptake inhibition, but the contribution to GLUT5 inhibition was higher than the contribution to GLUT2 inhibition.

Intestinal Fructose and Glucose Metabolism in Health and Disease

“…The ability of culinary plant extracts containing phytochemicals to inhibit fructose transport has also been assessed in Caco-2 cells. Lee et al found that demethoxycurcumin and curcumin from turmeric extracts inhibited fructose transport by GLUT2-and GLUT5-mediated fructose uptake, respectively [110]. Similarly, catechin from guava leaf (Psidium guajava) inhibited GLUT5-mediated fructose uptake, whereas quercetin inhibited both GLUT5-and GLUT2-mediated fructose transport [110].…”

“…Lee et al found that demethoxycurcumin and curcumin from turmeric extracts inhibited fructose transport by GLUT2-and GLUT5-mediated fructose uptake, respectively [110]. Similarly, catechin from guava leaf (Psidium guajava) inhibited GLUT5-mediated fructose uptake, whereas quercetin inhibited both GLUT5-and GLUT2-mediated fructose transport [110]. In addition, the ability of guava leaf and guava fruit extracts to inhibit glucose transport have also been demonstrated by Müller et al in Caco-2 cells and mice (C57BL/6N) [111].…”

Health Effects of Psidium guajava L. Leaves: An Overview of the Last Decade

“…Additionally, the individual flavonol-glycosides found in the guava extract reported no significant differences compared with the uptake of the whole guava extract into epithelial cells (CaCo-2) [60]. In the same cell line, the inhibition of fructose uptake was also tested by Lee et al [61], who confirmed that catechin and quercetin contributed to the inhibition of glucose transporters. In addition, the enhancement of aqueous guava leaf extract was investigated with regard to glucose uptake in rat clone 9 hepatocytes.…”

Suppressive effect of nobiletin and epicatechin gallate on fructose uptake in human intestinal epithelial Caco-2 cells

“…Therefore, inhibition of GLUT5 activity using dietary substances could offer an effective method for preventing fructose-induced diseases such as metabolic syndrome, hypertension, obesity, and NAFLD. However, little information is available regarding the food ingredients that could suppress intestinal fructose absorption, except for recent reports on a Eucalyptus globulus leaf extract and certain culinary plant extracts [11,12].…”