Catechins metabolism

Moridani, M.Y. et al., Catechin metabolism glutathione conjugate formation catalysed by tyrosinase, peroxidase and cytochrome P450, Chem. Res. Toxicol., 14, 841, 2001. 

Unlike some classes of polyphenols such as flavonols and flavones, flavanols are almost always present in the nonglycosylated form. Removal of glycoside from flavonoids, usually necessary before the transport across the intestinal barrier, is not required in the case of flavanols [Scalbert and Williamson, 2000]. The absorption of procyanidins by the small intestine was investigated by studying 14C-( + )-catechin, dimer, trimer, and procyanidin polymers permeation through Caco-2 cell cultures [Deprez et al., 2001]. There was little difference in permeability between monomer, dimmer, and trimer, based on the measurement of radioactivity present on the basal side of the cultures, whereas the permeability of the polymers was 10 times lower. The authors reported the absence of catechin metabolism but did not determine whether the radioactivity measured on the basal side of the cultures was from the parent dimers to polymers or from their products of degradation or metabolites, which could have resulted from instability of the parent compounds in the culture... 

Moridani MY, Scobie H, Salehi P, O Brien PJ. Catechin metabolism glutathione conjugate formation catalyzed by tyrosinase, peroxidase, and cytochrome p450. Chem Res Toxicol 2001 14 841 848. 

Higdon JV and Frei B. 2003. Tea catechins and polyphenols health effects, metabolism, and antioxidant functions. Crit Rev Food Sci Nutr 43(1) 89—143. Review. 

Scheline, R.R., The metabolism of (-l-)-catechin to hydroxyphenylvaleric acids by the intestinal microflora, Biochim. Biophys. Acta, 222, 228, 1970. 

The two principal classes of proanthocyanidins found (10) in plant tissues are the procyanidins (1, R e H) and the prodeTphin-idins (1, R s OH). Proanthocyanidins of mixed anthocyanidin character (1, R = H or OH) have been noted. In any tissue where proanthocyan din synthesis occurs there is invariably found a range of molecular species - from the monomeric flavan-3-ols (catechins, gallocatechins) to the polymeric forms (1) and biosynthetic work (11) suggests a very close relationship between the metabolism of the parent f1avan-3-o1 and the synthesis of proanthocyanidins, Figure 4. 

Other authors suggested that catechins are converted to glucuronyl derivatives in the intestinal mucosa and are further metabolized by methylation, sulfation and conjugation with glucuronic acid, sulfate and glycine [101]. 

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... 

Das NP. 1974. Studies on flavonoid metabolism. Excretion of m-hydroxyphenylhy-dracrylic acid from (plus)-catechin in the monkey (Macaca iris sp.). Drug Metab Dispos 2 209-213. 

Donovan JL, Crespy V, Manach C, Morand C, Besson C, Scalbert A, Remesy C. 2001. Catechin is metabolized by both the small intestine and liver of rats. J Nutr 131 1753-1757. 

Griffiths LA. 1964. Studies on flavonoid metabolism. Identification of the metabolities of ( + )-catechin in rat urine. Biochem J 92 173-179. 

Groenewoud G, Hundt HR. 1986. The microbial metabolism of condensed ( + )-catechins by rat-caecal microflora. Xenobiotica 16 99-107. 

The major metabolic pathways for tea catechins include glucuronidation, sulfation, and methylation. There are species and tissue-specific differences in... 

Silberberg, M. et al., Co-administration of quercetin and catechin in rats alters their absorption but not their metabolism, Life Sci., 77, 3156, 2005. 

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