ABSTRACT
The effect of red wine (RW), red grape juice (RGJ), green tea (GT), and representative polyphenols on Caco-2 cell (65)Zn uptake was explored. RW, RGJ, and GT enhanced the uptake of zinc from rice matrix. Fractionation of RW revealed that enhancing activity of zinc uptake was exclusively resided in the polyphenol fraction. Among the polyphenols tested, only tannic acid and quercitin stimulated the uptake of zinc while others did not influence the uptake. In tune with these results, only tannic acid and quercitin competed with zinquin (a zinc selective fluorophore) for zinc in vitro. Although all the polyphenols tested appear to enhance the expression of metallothionein (MT), the induction was higher with tannic acid, quercitin, and RW extract. Furthermore, phytic acid abrogated the tannic acid-induced MT expression. These results suggest that polyphenol-rich beverages, tannic acid, and quercitin bind and stimulate the zinc uptake and MT expression in Caco-2 cells.
Subject(s)
Absorption/drug effects , Beverages/analysis , Flavonoids/analysis , Flavonoids/pharmacology , Metallothionein/metabolism , Phenols/analysis , Phenols/pharmacology , Up-Regulation/drug effects , Zinc/pharmacokinetics , Binding, Competitive , Caco-2 Cells , Chelating Agents/chemistry , Digestion , Flavonoids/chemistry , Flavonoids/isolation & purification , Fruit/chemistry , Humans , Oryza/chemistry , Oryza/metabolism , Phenols/chemistry , Phenols/isolation & purification , Phytic Acid/analysis , Phytic Acid/pharmacology , Polyphenols , Quercetin/chemistry , Quercetin/pharmacology , Quinolones/chemistry , Seeds/chemistry , Seeds/metabolism , Tannins/analysis , Tannins/antagonists & inhibitors , Tannins/chemistry , Tannins/pharmacology , Tea/chemistry , Tosyl Compounds/chemistry , Vitis/chemistry , Wine/analysis , Zinc/analysis , Zinc/chemistry , Zinc Radioisotopes/pharmacokineticsABSTRACT
The kinetics, depletion/repletion of zinc, and effects of dietary ligands/food matrices on (65)Zn uptake was studied in Caco-2 cells. The uptake of zinc showed a saturable and nonsaturable component, depending upon the media zinc concentrations. Intracellular depletion increased zinc uptake, whereas zinc loading did not. Phytic acid and histidine inhibited zinc uptake, while tannic acid, tartaric acid, arginine, and methionine increased zinc uptake. Tannic acid at a 1:50 molar ratio promoted zinc uptake from wheat- and rice-based food matrices. Further, Caco-2 cells responded similarly with zinc and iron uptake when fed Indian bread prepared from low- and high-extraction wheat flour, representing low and high phytate content. However, inclusion of tea extract or red grape juice as a source of polyphenols enhanced the uptake of zinc while decreasing that of iron. These results suggest that the Caco-2 cells predict the correct direction of response to dietary ligands even from complex foods.
