Absorption and metabolism studies of hydrolysable and condensed tannins with an in vitro Caco2 transwell model

The interest in polyphenolic compounds was evoked by a growing body of epidemiological evidence that regular consumption of polyphenol rich foods prevents degenerative disease. In this context, the questions about bioavailability of polyphenolic compounds are of vital importance.

In the last years, numerous publications appeared on transport experiments applying a Caco2-transwell system. Human colonic cell line Caco-2 as a model of human intestinal absorption is useful to study the intestinal epithelial transport of bioactive compounds. The apical to basolateral flux and reverse as well as hydrolysis of glycosides and the glucuronidation and sulfation of phenolic substances by the enterocytes can be investigated. This literature-known and well-described model is intended to be used to give answers to the questions asked above.

The project aims to give answers to the following questions: how are tannins transformed during the digestion process? What are the size limits for absorption via intestinal Caco2 cells for condensed and hydrolysable tannins? Are the tannins absorbed without metabolic transformations or what are the actual metabolites arriving at the blood side of the model?

This demanding project gives profound insight into the absorption process of hydrolysable and condensed tannins. Health-promoting effects of functional foods are determined not only by the content of bioactive compounds but also by their bioavailability. Therefore, the knowledge gained in this project will give information about the selection of raw material but also the processing of functional food, in a way which enables to incorporate a maximum content of absorbable bioactive compounds into the final product.

A. Kosińska, Y. Xie, S. Diering, J. Héritier, W. Andlauer: Stability of Phenolic Compounds Isolated from Cocoa, Green Tea and Strawberries in Hank’s Balanced Salt Solution under Cell Culture Conditions. Polish Journal of Food and Nutrition Sciences 2012, 62, 91-96

A. Kosińska, W. Andlauer: Cocoa polyphenols are absorbed in Caco-2 model of intestinal epithelium. Food Chemistry 1012, 135, 999-1005

Xie Y., Kosińska A., Xu H., Andlauer W., Milk enhances intestinal absorption of green tea catechins in in vitro digestion/Caco-2 cells model, Food Research International 2013, 53, 793-800

Kosińska A., Andlauer W., Modulation of TJ integrity by food components. Food Research International 2013, 54, 951–960