ABSTRACT
Ellagitannins are hydrolyzable tannins that release ellagic acid upon hydrolysis. They exhibit various biological activities in vitro that have been associated with pharmacological (ellagitannin-containing medicinal plants) and nutritional (ellagitannin-containing foods) effects in vivo. The potential health effects are mainly related to the prevention of cardiovascular diseases and cancer. In vivo biological effects may be due partially to the potent free-radical scavenging activity that these compounds exert in vitro. It is, however, necessary to take into account the fate of ellagitannins in the gastrointestinal tract, their bioaccessibility, bioavailability, metabolism, and tissue distribution of the corresponding metabolites to understand the efcacy and the physiological role of dietary and medicinal ellagitannins. In the present chapter, we review the current knowledge regarding the bioavailability and
9.1 Introduction .................................................................................................. 183 9.2 Relevance of Ellagitannins in the Diet ......................................................... 184 9.3 Models to Study Bioavailability and Metabolism ........................................ 184
9.3.1 In Vitro Uptake and Metabolism ...................................................... 187 9.3.2 In Vivo Studies Using Animal Models ............................................. 188 9.3.3 Human Studies .................................................................................. 191
9.4 Bioavailability and Metabolism Events in Different Body Sites .................. 193 9.4.1 Absorption of Ellagic Acid ............................................................... 193 9.4.2 Intestinal Microbiota Metabolism .................................................... 193 9.4.3 Phase I and Phase II Metabolism...................................................... 194 9.4.4 Tissue Distribution ............................................................................ 194
9.5 The Whole Picture of Ellagitannin Bioavailability ...................................... 195 9.6 Conclusions ................................................................................................... 195 Acknowledgments .................................................................................................. 196 References .............................................................................................................. 196
metabolism of ellagitannins and point out various unresolved issues within these processes in humans that require further research.
