Bioavailability of catechins

Gu, L. House, S.E. Rooney, L.W. Prior, R.L. 2008. Sorghum extrusion increases bioavailability of catechins in weanling pigs. J. Agric. Food Chem. 56 1283-1288. Gu, L. House, S.E. Wu, X. Ou, B. Prior, R.L. 2006. Procyanidin and catechin contents and antioxidant capacity of cocoa and chocolate products. J. Agric. Food Chem. 54 4057-4061. 

Bioavailability of Catechins Affected by Pure or Mixed Form and... 

BIOAVAILABILITY OF CATECHINS AFFECTED BY PURE OR MIXED FORM AND FOOD MATRIX... 

Some tea catechin metabolites have been identified in humans after oral ingestion, including the glucuronide, sulfate, and methylation forms of catechins and their microbial metabolites. Some of these metabolites have higher plasma concentrations than their parent compounds. However, the structures of other metabolites of tea catechins still need to be identified, and bioavailability of catechins in humans still needs to be determined in order to understand the biological activities of tea catechins in vivo. 

Several studies have been conducted on the anti-inflammatory and anticarcino-genic activities of both green tea and black tea, as discussed in this chapter. However, the effect that is observed in vitro and in certain in vivo experiments is not reproducible in the human situation. This could be due to several confounding factors involved in epidemiological studies, or to the poor bioavailability of catechins. More detailed mechanistic studies are warranted to understand the effects of tea catechins in vivo so that they can be made applicable to the human situation. ... 

High concentrations of hydroalcoholic green tea extracts have been shown to exert acute toxicity in rat liver cells in vitro. The compound (-)-epigallocatechin-3-gal-late (EGCG) was noted as the constituent that was likely responsible for this effect. The bioavailability of catechins is relatively low with oral ingestion, however, suggesting that EGCG is not responsible for the hepatotoxicity reported in human studies (Schmidt et al. 2005). 

The book includes an introductory overview on food factors and then perspective chapters on bioavailability of catechins and chemistry of structured and nutraceutical lipids. Subsequent sections cover signal transduction, gene modulation, biomarker, and animal model studies as affected by food bioactives. Finally, the chemistry and bioactivity of antioxidative compounds associated fruits, vegetables, and other plants are presented. 

Donovan JL, Crespy V, Oliveira M, Cooper KA, Gibson BB, Williamson G (2006) (-t)-Catechin is more bioavailable than (-)-Catechin relevance to the bioavailability of catechin from cocoa. Free Radio Res 40 1029-1034... 

The bioavailability and metabolism of catechins was studied in humans after consumption of black tea containing 15.48 mg of EGC, 36.54 mg of... 

Lambert, J.D. et al., Piperine enhances the bioavailability of the tea polyphenol (-)-epigallo-catechin-3-gallate in mice, J. Nutr., 134, 1948, 2004. 

Cai, Y., Anavy, N.D., and Chow, H.H., Contribution of presystemic hepatic extraction to the low oral bioavailability of green tea catechins in rats. Drug Metab. Dispos., 30, 1246, 2002. 

Bioavailability of tea catechins in tissues may be much more important than that in plasma, but little published data are available on tissue distribution of catechins in humans after tea consumption, even in animals. The nature of tissue metabolites... 

Chow, H.-H. S., Hakim, 1. A., Vining, D. R., Crowell, J. A., Ranger-Moore, J., Chew, W. M., Celaya, C. A., Rodney, S. R., Hara, Y, and Alberts, D. S. 2005. Effects of dosing condition on the oral bioavailability of green tea catechins after single-dose administration of Rolyphenon E in healthy individuals. Clin. Cancer Res. 11 4627-33. 

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