Inhibition of Folic Acid Uptake by Catechins and Tea Extracts in Caco-2 Cells

Alemdaroglu, N. Ceren; Wolffram, Siegfried; Boissel, J. P.; Closs, Ellen I.; Spahn‐Langguth, Hildegard; Langguth, Peter

doi:10.1055/s-2006-951745

Cited by 35 publications

(36 citation statements)

References 26 publications

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“…Other phenolic compounds such as myricetin, quercetin and kaempferol can also be found in teas (14) and may also contribute to inhibition of 3 H-FA and 3 H-MTX uptake. In agreement with the results from Lemos et al (78) , green and black tea extracts, as well as two catechins contained in green tea (EGCG and epicatechin gallate (ECG)), were also found to inhibit FA uptake by Caco-2 cells (80) . The difference in the effect of red wine in relation to 3 H-FA uptake in Caco-2 cells (inhibition) (78) and rat jejunum (no effect) (60) can be explained by, at least, two important differences.…”

Section: Effect Upon [supporting

confidence: 91%

Effect of polyphenols on the intestinal and placental transport of some bioactive compounds

2010

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Polyphenols are a group of widely distributed phytochemicals present in most foods of vegetable origin. A growing number of biological effects have been attributed to these molecules in the past few years and only recently has their interference with the transport capacity of epithelial barriers received attention. This review will present data obtained concerning the effect of polyphenols upon the transport of some compounds (organic cations, glucose and the vitamins thiamin and folic acid) at the intestinal and placental barriers. Important conclusions can be drawn: (i) different classes of polyphenols affect transport of these bioactive compounds at the intestinal epithelia and the placenta; (ii) different compounds belonging to the same phenolic family often possess opposite effects upon transport of a given molecule; (iii) the acute and chronic/short-term and long-term exposures to polyphenols do not produce parallel results and, therefore, care should be taken when extrapolating results; (iv) the effect of polyphenolics in combination may be very different from the expected ones taking into account the effect of each of these compounds alone, and so care should be taken when speculating on the effect of a drink based on the effect of one component only; (v) care should be taken in drawing conclusions for alcoholic beverages from results obtained with ethanol alone. Although most of the data reviewed in the present paper refer to in vitro experiments with cell-culture systems, these studies raise a concern about possible changes in the bioavailability of substrates upon concomitant ingestion of polyphenols.

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Section: Effect Upon [supporting

confidence: 91%

Effect of polyphenols on the intestinal and placental transport of some bioactive compounds

2010

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“…Using an in vitro enzyme activity assay, we observed a time-and dose-dependent inhibition of dihydrofolate reductase activity by EGCG and a green tea extract (47). A recent cell culture study showed that certain gallated derivatives of green tea polyphenols, namely EGCG, the predominant catechin in green tea, and epicatechin gallate, inhibited folic acid uptake in Caco-2 cells (48). In our studies in rats, green tea extract significantly decreased serum 5-methyl-tetrahydrofolate concentrations (47).…”

Section: Current Status Of Knowledgesupporting

confidence: 52%

Which Sources of Flavonoids: Complex Diets or Dietary Supplements?

Egert

Rimbach

2011

Advances in Nutrition

186

100

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There is increasing interest in the potential health benefits of dietary flavonoids. Fruits and vegetables, tea, and cocoa are rich natural sources of flavonoids. Epidemiological studies have indicated that consumption of these foods is likely to be associated with a reduced risk of cardiovascular disease, but the etiology of this benefit is not yet clearly defined. Furthermore, in some acute interventions, a positive effect of tea and cocoa on vascular function has been reported. An alternative source of flavonoids is dietary supplements, which have become increasingly popular in the recent past. In this context, it needs to be critically evaluated whether vascular health-promoting and other positive properties of flavonoid-rich diets can be replaced by purified flavonoids as dietary supplements. Plant sources of flavonoids contain a complex mixture of secondary plant metabolites and not only flavonoids per se. This complex mixture of secondary plant metabolites cannot be simply exchanged by single purified compounds as dietary supplements. If flavonoids are given as dietary supplements, toxicity issues as well as nutrient drug interactions need to be taken into account. Purified flavonoids given in high doses as dietary supplements may affect trace element, folate, and vitamin C status. Furthermore, they may exhibit antithyroid and goitrogenic activities. In this review article, the available literature on the safety issues surrounding high dose supplemental flavonoid consumption has been summarized.

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“…Such possible, yet unpredictable effects through (increased) tea consumption might arise from the enzymeand transporter-related interactions of such tea specimens [14,35,36]. Since several of their catechin-derived components (mainly EGCG and ECG) as well as black tea and green tea inhibited the uptake of folic acid in Caco-2 cells, suggesting a potential interaction during the absorption step [28], the present in vivo study was designed to challenge the hypothesis that tea extracts taken concomitantly with folic acid might diminish folate absorption and thus the systemic availability of folates also under clinical conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Since nutritional intake of folic acid often might be at the lower level of dietary recommendations [26,27], possible food-and herb-interactions that may lead to a decreased systemic availability of folates could be critical. In this context, an in vitro interaction between folic acid and extracts of green and black tea as well as tea catechins at the level of cellular uptake using Caco-2 cell monolayers was demonstrated recently [28]. In that study, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) inhibited the cellular folic acid uptake with IC 50 values of 34.8 and 30.8 mmol/l, respectively.…”

Section: Introductionmentioning

confidence: 95%

Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability

Alemdaroglu

Dietz

Wolffram

et al. 2008

Biopharm & Drug Disp

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Previous in vitro studies using Caco-2 cell monolayers suggested a possible interaction between green and black tea and folic acid at the level of intestinal absorption. The main purpose of the present study was to investigate a possible pharmacokinetic interaction between tea and folic acid in healthy volunteers. In an open-labeled randomized cross-over study, the pharmacokinetic interaction between tea and folic acid (0.4 mg and 5 mg) was investigated in healthy volunteers. Water was used as the reference drink. Subjects ingested 0.4 mg folic acid tablets with water, green or black tea (0.3 g extract/250 ml) or 5 mg folic acid tablets with water or green tea (0.3 g extract/250 ml). Blood samples were collected over a period of 8 h. Serum folate analysis was carried out by a competitive immunoassay which uses direct chemiluminescent technology. At the 0.4 mg folic acid dose, green and black tea reduced the mean C(max) of serum folate by 39.2% and 38.6%, and the mean AUC(0 --> infinity) by 26.6% and 17.9%, respectively. At the 5 mg folic acid dose, the mean C(max) of serum folate was reduced by 27.4% and the mean AUC(0 --> infinity) was decreased significantly by 39.9% by the co-application of green tea. The present results suggest an in vivo interaction between tea and folic acid with even low concentrations of green and black tea extracts yielding decreased bioavailabilities of folic acid.

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Inhibition of Folic Acid Uptake by Catechins and Tea Extracts in Caco-2 Cells

Cited by 35 publications

References 26 publications

Effect of polyphenols on the intestinal and placental transport of some bioactive compounds

Effect of polyphenols on the intestinal and placental transport of some bioactive compounds

Which Sources of Flavonoids: Complex Diets or Dietary Supplements?

Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability

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