Epigallocatechin-3-O-gallate / epigallocatechin / epicatechin breakdown pathway (Homo sapiens)

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Schematic representation of the metabolism of flavan-3-ols in the human body. Full arrows represent a direct link (most likely one enzyme or step involved), whereas dashed arrows represent most likely several enzymes or steps. Please note that the structures are found in human urine as conjugates with glucuronide, sulfate, and/or methyl groups. Flavan-3-ols are compounds abundant in food products like green tea, red wine, and chocolate. As a result of many people consuming one or more of these food products, the (conjugated) breakdown products of flavan-3-ols are often encountered in human urine. The breakdown is mostly the result of gut microbes that convert the food metabolites through different routes towards small phenolic acids and eventually benzoic acid that readilly forms a conjugate with glycine to result in hippuric acid, a common gut microbial product. A complete list of the conjugates encountered in urine after tea intake can be found with the study of Van der Hooft et al. (2012).

The scheme was adapted from Roowi et al. (2010) based on the urinary compounds annotated and identified in the study by Van der Hooft et al. (2012).

Green tea flavan-3-ols: Colonic degradation and urinary excretion of catabolites by humans Roowi, Suri; Stalmach, Angelique; Mullen, William; Lean, Michael E. J.; Edwards, Christine A.; Crozier, Alan Journal of Agricultural and Food Chemistry (2010), 58 (2), 1296-1304 CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Structural Elucidation and Quantification of Phenolic Conjugates Present in Human Urine after Tea Intake Justin J. J. van der Hooft, Ric C. H. de Vos, Velitchka Mihaleva, Raoul J. Bino, Lars Ridder, Niels de Roo, Doris M. Jacobs, John P. M. van Duynhoven, and Jacques Vervoort Analytical Chemistry 2012 84 (16), 7263-7271 DOI: 10.1021/ac3017339