Effects of dietary bioactive polyphenols on iron transport in human intestinal Caco‐2 cells

Abstract

There is persuasive epidemiological evidence that consumption of bioactive dietary polyphenolic compounds, which are present in fruits, vegetables, some types of grain, red wine and tea, promote human health. Bioactive dietary polyphenolic compounds reportedly have a wide range of effects in vivo and vitro, including metal chelating activities. Tea and other beverages rich in phenolic compounds were shown to inhibit the absorption of non‐heme iron. Because iron deficiency is the most common nutritional deficiency and the mode action of these compounds includes chelation of metals such as iron, it is prudent to examine the effects of dietary bioactive polyphenols on iron absorption. Initially, we examined effects of epigallocatechin‐o‐gallate (EGCG), a major polyphenolic component of a green tea, and grape seed extract (GSE) on intestinal iron transport. The fully differentiated Caco‐2 cells grown on microporous membrane inserts were used to examine effects of bioactive dietary polyphenolic compounds on the absorption of non‐heme iron. The transepithelial transport of 55Fe from the apical compartment into the basolateral compartment was 17.6 ± 2.2 pmol/mg protein during 3h incubation. Addition of 10‐fold molar excess of EGCG and GSE decreased 55Fe transport by 98 ± 0.3 and 97.1±0.2 %, respectively. These results demonstrate the inhibitory influence of dietary bioactive polyphenols on the absorption of non‐heme iron.