Formation of antioxidants from (-)-epigallocatechin gallate in mild alkaline fluids, such as authentic intestinal juice and mouse plasma.

  title={Formation of antioxidants from (-)-epigallocatechin gallate in mild alkaline fluids, such as authentic intestinal juice and mouse plasma.},
  author={K. Yoshino and M. Suzuki and K. Sasaki and T. Miyase and M. Sano},
  journal={The Journal of nutritional biochemistry},
  volume={10 4},
The oxidative dimerization of (-)-epigallocatechin gallate (EGCG), the major catechin of tea leaves (Camellia sinensis L.), in authentic intestinal juice (pH 8.5) and mouse plasma (pH 7.8) was investigated. EGCG was unstable in the alkaline solutions over pH 7.4. The content of EGCG was decreased to 19.4% and 60.7% at 5 minutes in the intestinal juice and plasma, respectively. Three products-P-1 (theasinensin A), P-2 (a new dimerized product reported in a previous paper), and P-3 (theasinensin… Expand
Isolation and structural elucidation of dimeric epigallocatechin-3-gallate autoxidation products and their antioxidant capacity
Dietary polyphenols like epigallocatechin-3-gallate (EGCG)—which represents the most abundant flavan-3-ol in green tea—are subject of several studies regarding their bioactivity and health-relatedExpand
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Research Doctorate - Doctor of Philosophy (PhD)%%%%Background: The catechin, (-)-epigallocatechin-3-O-gallate (EGCG), the most abundant compound in green tea, has been linked to numerous beneficialExpand
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Flavonoids from a grape seed extract interact with digestive secretions and intestinal cells as assessed in an in vitro digestion/Caco-2 cell culture model
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Stability, cellular uptake, biotransformation, and efflux of tea polyphenol (-)-epigallocatechin-3-gallate in HT-29 human colon adenocarcinoma cells.
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Bioavailability of flavan-3-ols and procyanidins: gastrointestinal tract influences and their relevance to bioactive forms in vivo.
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Tea catechin auto-oxidation dimers are accumulated and retained by Caco-2 human intestinal cells.
Data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium, suggesting intracellular oxidative conversion of THSNs to P-2. Expand
Effect of (−)-epigallocatechin gallate at different pH conditions on enteric viruses
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Colon Adenocarcinoma Cells )-Epigallocatechin-3-Gallate in HT-29 Human − Polyphenol ( Stability , Cellular Uptake , Biotransformation , and Efflux of Tea Updated
The biological effects of ( )-epigallocatechin-3-gallate (EGCG) have been extensively investigated in cell lines, but its stability and interactions with cells under culture conditions are unclear.Expand
Stabilizing Effect of Grape Seed Extract on Ascorbic Acid
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Stability of Green Tea Catechins
Green tea catechins (GTCs), which include (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC) and (−)-epigallocatechin gallate (EGCG), possess a variety of biologicalExpand
Absorption and distribution of tea catechin, (-)-epigallocatechin-3-gallate, in the rat.
The results indicate that tea catechin, E GCg, is absorbed from the digestive tract, with the intestinal mucosa the most enriched of the organelles, which may explain the potent antioxidant function of EGCg in inhibiting colon mucosal phospholipid hydroperoxidation in the prevention of rat colonic carcinogenesis. Expand
Antioxidative effects of black tea theaflavins and thearubigin on lipid peroxidation of rat liver homogenates induced by tert-butyl hydroperoxide.
It is suggested that black tea infusion containing TFs and TR could inhibit lipid peroxidation in biological conditions in the same way as greenTea infusion containing epicatechins. Expand
Evaluation of the antioxidant actions of ferulic acid and catechins.
The results show that catechins and ferulic acid possess antioxidant properties, which may become important given the current search for "natural" replacements for synthetic antioxidant food additives. Expand
Formation of Radicals and Chemiluminescence during the Autoxidation of Tea Catechins
Four catechins, (–)-epicatechin (EC), (–)-epigallocatechin (EG), (–)-epicatechin gal late (ECg) and (–)-epigallocatechin gallate (EGg), extracted from tea were investigated with respect to theExpand
Tannins and Related Compounds. CXIV. Structure of Novel Fermentation Products, Theogallinin, Theaflavonin and Desgalloyl Theaflavonin from Black Tea, and Changes of Tea Leaf Polyphenols during Fermentation
Continuing chemical examination of black tea has led to the isolation of three novel fermentation products, theogallinin (1), theaflavonin (10) and desgalloyl theaflavonin (11). The structure of 1Expand
Absorption, Distribution, and Elimination of Tea Polyphenols in Rats
Tea polyphenols-including (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC)-are believed to be responsible for the beneficial effects of tea. This study wasExpand
Studies on protective mechanisms of four components of green tea polyphenols against lipid peroxidation in synaptosomes.
The results indicated that the ability of those compounds to protect synaptosomes from the damage of lipid peroxidation initiated by Fe2+/Fe3+ was dependent not only on their iron-chelating activity and free-radical scavenging activity, but also on the stability of their semiquinone free radicals. Expand
Accumulation of (-)-epicatechin metabolites in rat plasma after oral administration and distribution of conjugation enzymes in rat tissues.
It has been proposed that the first detoxification step of dietary EC, namely, glucuronidation, occurs at the level of the intestinal mucosa in rats, and EC enters the common blood circulation exclusively in the glucuronized form. Expand
Analysis of plasma and urinary tea polyphenols in human subjects.
  • M. Lee, Z. Wang, +5 authors C. Yang
  • Chemistry, Medicine
  • Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
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Methods for the analysis of tea polyphenols in human plasma and urine samples using HPLC with the coulochem electrode array detection system to develop biomarkers for tea consumption established good quantitative relationships for a large concentration range of teapolyphenols. Expand