Berries are a rich source of polyphenolic compounds such as flavonoids, including anthocyanins, with wide-ranging potential therapeutic effects(Reference Zafra-Stone, Yasmin and Bagchi1). It has been demonstrated previously that intestinal uptake of dietary glucose is impeded by the presence of polyphenolic compounds; however, little is known regarding the genes involved in this mechanism(Reference Kwon, Eck and Chen2). The aim of this study was to investigate the effects of an anthocyanin-rich berry-extract on dietary glucose transporting genes in Caco-2 cells.
Human intestinal Caco-2 cells were cultured for 19 d and were then treated for 16 h with an anthocyanin-rich berry-extract (OptiBerry; InterHealth Nutraceuticals, Benicia, CA, USA) at a final concentration of 0.5% (w/v). Subsequently mRNA was isolated and used for the quantitative real-time polymerase chain reaction (qRT–PCR), using 18S and GAPDH as housekeeping genes. Gene expression data are expressed as means (±sem) relative expression ratios of control; n=5/6.
The expression of GLUT2 (apical/basolateral monosaccharide transporter), GLUT5 (apical fructose transporter) and SGLT1 (apical sodium/glucose co-transporter) was decreased by the berry-extract treatment. GLUT2, GLUT5 and SGLT1 expression as a ratio of the control was as follows: GLUT2 (0.20±0.02; P=1.9×10−4), GLUT5 (0.57±0.08; P=2.5×10−3) and SGLT1 (0.45±0.03; P=3.1×10−2).
GLUT2, GLUT5 and SGLT1 have previously been identified as therapeutic targets for dysregulated glucose metabolism. In this study, the expression of these genes in Caco-2 cells was decreased by treatment with an anthocyanin-rich berry-extract. Studies are in progress to investigate the biological relevance of the observed effects in relation to berry consumption and the absorption of dietary sugar.
