The microbial metabolism of condensed (+)-catechins by rat-caecal microflora

Groenewoud, G.; Hundt, H. K. L.

doi:10.3109/00498258609043512

Cited by 64 publications

(40 citation statements)

References 20 publications

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“…3). The possible depolymerization of dimeric structures into monomeric units, firstly proposed by Groenewoud et al, 64 has been recently confirmed to occur but to a lesser extent, 54,61 representing less than 10% in the case of procyanidin B2. 61 Other microbial metabolites arising exclusively from the catabolism of dimeric procyanidins have recently been identified, such as 5-(2 0 ,4 0 -dihydroxyphenyl)-2-ene-valeric acid, as well as other compounds which have been tentatively identified as derivatives from the A-ring of the upper unit, including the interflavanic bond.…”

Section: Iii2 Metabolites Arising From the Catabolism Of Dimeric Promentioning

confidence: 82%

Insights into the metabolism and microbial biotransformation of dietary flavan-3-ols and the bioactivity of their metabolites

et al. 2010

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Flavan-3-ols, occurring in monomeric, as well as in oligomeric and polymeric forms (also known as condensed tannins or proanthocyanidins), are among the most abundant and bioactive dietary polyphenols, but their in vivo health effects in humans may be limited because of their recognition as xenobiotics. Bioavailability of flavan-3-ols is largely influenced by their degree of polymerization; while monomers are readily absorbed in the small intestine, oligomers and polymers need to be biotransformed by the colonic microbiota before absorption. Therefore, phenolic metabolites, rather than the original high molecular weight compounds found in foods, may be responsible for the health effects derived from flavan-3-ol consumption. Flavan-3-ol phenolic metabolites differ in structure, amount and excretion site. Phase II or tissular metabolites derived from the small intestine and hepatic metabolism are presented as conjugated derivatives (glucuronic acid or sulfate esters, methyl ether, or their combined forms) of monomeric flavan-3-ols and are preferentially eliminated in the bile, whereas microbial metabolites are rather simple conjugated lactones and phenolic acids that are largely excreted in urine. Although the colon is seen as an important organ for the metabolism of flavan-3-ols, the microbial catabolic pathways of these compounds are still under consideration, partly due to the lack of identification of bacteria with such capacity. Studies performed with synthesized or isolated phase II conjugated metabolites have revealed that they could have an effect beyond their antioxidant properties, by interacting with signalling pathways implicated in important processes involved in the development of diseases, among other bioactivities. However, the biological properties of microbederived metabolites in their actual conjugated forms remain largely unknown. Currently, there is an increasing interest in their effects on intestinal infections, inflammatory intestinal diseases and overall gut health. The present review will give an insight into the metabolism and microbial biotransformation of flavan-3-ols, including tentative catabolic pathways and aspects related to the identification of bacteria with the ability to catabolize these kinds of polyphenols. Also, the in vitro bioactivities of phase II and microbial phenolic metabolites will be covered in detail.

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Section: Iii2 Metabolites Arising From the Catabolism Of Dimeric Promentioning

confidence: 82%

Insights into the metabolism and microbial biotransformation of dietary flavan-3-ols and the bioactivity of their metabolites

et al. 2010

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“…These compounds are then available for absorption by the colon [67,69]. The importance of this microbial degradation pathway needs to be studied further.…”

Section: Biotransformation and Pharmacokinetics Of Pcsmentioning

confidence: 99%

Bioavailability issues in studying the health effects of plant polyphenolic compounds

Yang¹,

Sang

Lambert

et al. 2008

Mol. Nutr. Food Res.

186

209

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Polyphenolic compounds are common in the diet and have been suggested to have a number of beneficial health effects including prevention of cancer, cardiovascular disease, diabetes, and others. For some dietary polyphenols, certain benficial effects are suggested by epidemiological studies, some are supported by studies in animal models, and still others are extrapolated from studies in vitro. Because of the relatively poor bioavailability of many of these compounds, the molecular basis of these beneficial effects is not clear. In the present review, we discuss the potential health benefits of dietary polyphenols from the point of view of bioavailability. Tea catechins, curcumin, and proanthocyanidins are used as examples to illustrate some of the problems that need to be resolved. Further research on both the biological activity and bioavailability of dietary polyphenols is needed to properly assess their usefulness for the prevention and treatment of disease.

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“…The degree of polymerization of proanthocyanidins has also been reported to decrease in the rat small intestine (Abia & Fry, 2001). Other authors also suggested that procyanidin dimers might be degraded into catechin monomers by microflora in the colon although they did not report the presence of catechin as an intermediate breakdown product in their in vitro experiments (Groenewoud & Hundt, 1986;Déprez et al 2000). In the present study, no catechin was detected in the plasma or urine of the rats fed the meal containing 20 mg purified procyanidin dimer B 3 indicating that this procyanidin was not cleaved into a bioavailable source of catechin in the stomach or large intestine.…”

Section: Discussionmentioning

confidence: 46%

“…Furthermore, more biological effects of procyanidins in inner tissues could be mediated by some metabolites formed in the colon and then absorbed through the colon barrier. Procyanidin B 3 dimer and procyanidin polymers can be degraded by microflora in the large intestine into bioavailable phenolic acids similar to those formed from catechin itself (Scheline, 1970;Groenewoud & Hundt, 1986;Déprez et al 2000). Studies have identified mono-and dihydroxylated phenylpropionic, phenylacetic and hippuric acid as well as various phenylvalerolactones as flavanol metabolites in plasma (Das, 1971;Hackett et al 1983;Pietta et al 1998;Li et al 2000).…”

Section: Discussionmentioning

confidence: 99%

Procyanidins are not bioavailable in rats fed a single meal containing a grapeseed extract or the procyanidin dimer B<SUB>3</SUB>

Donovan¹,

Manach²,

Rios³

et al. 2002

British Journal of Nutrition

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Flavanols are the most abundant flavonoids in the human diet where they exist as monomers, oligomers and polymers. In the present study, catechin, the procyanidin dimer B 3 and a grapeseed extract containing catechin, epicatechin and a mixture of procyanidins were fed to rats in a single meal. After the meals, catechin and epicatechin were present in conjugated forms in both plasma and urine. In contrast, no procyanidins or conjugates were detected in the plasma or urine of any rats. Procyanidins were not cleaved into bioavailable monomers and had no significant effects on the plasma levels or urinary excretion of the monomers when supplied together in the grapeseed extract. We conclude that the nutritional effects of dietary procyanidins are unlikely to be due to procyanidins themselves or monomeric metabolites with the intact flavonoid-ring structure, as they do not exist at detectable concentrations in vivo. Future research should focus on other procyanidin metabolites such as phenolic acids and on the effects of the unabsorbed oligomers and polymers on the human gastrointestinal tract.

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The microbial metabolism of condensed (+)-catechins by rat-caecal microflora

Cited by 64 publications

References 20 publications

Insights into the metabolism and microbial biotransformation of dietary flavan-3-ols and the bioactivity of their metabolites

Insights into the metabolism and microbial biotransformation of dietary flavan-3-ols and the bioactivity of their metabolites

Bioavailability issues in studying the health effects of plant polyphenolic compounds

Procyanidins are not bioavailable in rats fed a single meal containing a grapeseed extract or the procyanidin dimer B<SUB>3</SUB>

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