- Rapid conversion of tea catechins to monomethylated products by rat liver cytosolic catechol-O-methyltransferase
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1. The metabolic O-methylation of several catechol-containing tea polyphenols by rat liver cytosolic catechol-O-methyltransferase (COMT) has been studied. 2. When (-)-epicatechin was used as substrate, its O-methylation showed dependence on incubation time, cytosolic protein concentration, incubation pH and concentration of S-adenosyl-L-methionine. The O-methylation of increasing concentrations of (-)-epicatechin followed typical Michaelis-Menten kinetics, and the apparent Km and Vmax were 51 μM and 2882 pmol mg protein-1 min-1, respectively, at pH 7.4, and were 17 μM and 2093 pmol mg protein-1 min-1, respectively, at pH 10.0. 3. Under optimized conditions for in vitro O-methylation, (-)-epicatechin, (+)-epicatechin and (-)-epigallocatechin were rapidly O-methylated by rat liver cytosol. In comparison, (-)-epicatechin gallate and (-)-epigallocatechin gallate were O-methylated at significantly lower rates under the same reaction conditions. 4. COMT-catalysed O-methylation of (-)-epicatechin and (-)-epigallocatechin was inhibited in a concentration-dependent manner by S-adenosyl-L-homocysteine, a demethylated product of S-adenosyl-L-methionine. The IC50 was ca. 10 μM. 5. In summary, the results showed that several catechol-containing tea polyphenols were rapidly O-methylated by rat liver cytosolic COMT. These observations raise the possibility that some of the biological effects of tea polyphenols may be exerted by their O-methylated products or may result from their potential inhibition of the COMT-catalysed O-methylation of endogenous catecholamines and catechol oestrogens.
- Zhu, Bao Ting,Patel, Ushma K.,Cai, May Xiaoxin,Lee, Anthony J.,Conney, Allen H.
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- Enzymatic O-methylation of flavanols changes lag time, propagation rate, and total oxidation during in vitro model triacylglycerol-rich lipoprotein oxidation
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3′-O-Methyl derivatives of flavan-3-ols, (+)-catechin (C), (-)-epicatechin (EC), and (-)-catechin gallate (CG) were prepared enzymatically. Hexanal (EC and CG family, 5 mmol/L) and conjugated diene (C and EC family, 0.25-10 mmol/L) formation following CuS
- Yu, Jun,Smith, Gabe,Gross, Heidrun B.,Hansen, Robert J.,Levenberg, John,Walzem, Rosemary L.
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- Synthesis and quantitative analysis of plasma-targeted metabolites of catechin and epicatechin
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Grape seed polyphenolic extract (GSPE) rich in the flavan-3-ols (+)-catechin and (-)-epicatechin beneficially modulates Alzheimers Disease phenotypes in animal models. The parent molecules in the extract are converted to a series of methylated and glucuronidated derivatives. To fully characterize these metabolites and establish a robust quantitative assay of their levels in biological fluids, we have implemented a partial synthetic approach utilizing chemical methylation followed by enzymatic glucuronidation. Liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS) and nuclear magnetic resonance (NMR) spectroscopy were used to assign unequivocal structures to the compounds. An analytical method using solid-phase extraction and LC-MS/MS in selective reaction monitoring mode (SRM) was validated for their quantitation in plasma. These studies provide a basis for improvements in future work on the bioavailability, metabolism, and mechanism of action of metabolites derived from dietary flavan-3-ols in a range of interventions.
- Blount, Jack W.,Redan, Benjamin W.,Ferruzzi, Mario G.,Reuhs, Bradley L.,Cooper, Bruce R.,Harwood, John S.,Shulaev, Vladimir,Pasinetti, Giulio,Dixon, Richard A.
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p. 2233 - 2240
(2015/03/14)
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- METHODS AND COMPOSITIONS FOR TREATMENT OF ISCHEMIC CONDITIONS AND CONDITIONS RELATED TO MITOCHONDRIAL FUNCTION
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The present invention relates to compositions and methods for prophylactic and/or therapeutic treatment of conditions related to mitochondrial function. In various aspects, the present invention comprises administering one or more compounds selected from the group consisting of epicatechin, an epicatechin derivative, catechin, a catechin derivative, nicorandil, and a nicorandil derivative in an amount effective to stimulate mitochondrial function in cells. The methods and compositions described herein provide for reducing infarct size in the heart following permanent ischemia or ischemia /reperfusion (IR) event or method for delaying, attenuating or preventing adverse cardiac remodeling, and can assist in prevention of impaired mitochondria biogenesis and thus prevention of the consequences of impaired mitochondrial biogenesis in various diseases and conditions, as well as provide for the active therapy of mitochondrial depletion that may have already occurred.
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Page/Page column 40-41
(2010/11/04)
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- Preparation and characterization of Catechin sulfates, glucuronides, and methylethers with metabolic interest
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Catechins are major polyphenols in many plant foods that have been related to health promotion. In the human organism they are largely metabolized to different conjugates (sulfates, glucuronides, and methylethers), which are further found in plasma and would contribute to the biological effects associated with the intake of the parent compounds. Circulating metabolites are likely to possess biological properties different from those of the original compounds, and therefore, it is important to evaluate their activity, for which sufficient amounts of them are required that cannot be obtained by isolation from biological fluids. This paper describes the preparation of the methyl, sulfate, and glucuronide derivatives of catechins using different chemical syntheses and their characterization by HPLC-DAD-ESI/MS. MS2 fragmentation of the compounds was also described that allowed the determination of the location of the different substituents on the catechin aglycones. The procedures optimized allowed the preparation of (epi)catechin sulfates, glucuronides, and methylethers conjugated at positions 3' and 4', as well as the sulfates at positions 5 and 7 with satisfactory yields for their further isolation by semipreparative-HPLC in view of their use in in vitro/ex vivo assays.
- Gonzalez-Manzano, Susana,Gonzalez-Paramas, Ana,Santos-Buelga, Celestino,Duenas, Montserrat
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experimental part
p. 1231 - 1238
(2010/06/14)
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- Boosting immunity
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The invention relates to compositions, and methods of use thereof, for boosting immunity, e.g. innate immunity, in a subject in need thereof comprising administering to the subject certain polyphenols such as flavanols, procyanidins, or pharmaceutically a
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Page/Page column 8; 9
(2008/06/13)
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- Flavonoid 3′-O-methyltransferase from rice: cDNA cloning, characterization and functional expression
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Plant O-methyltransferases (OMTs) are known to be involved in methylation of plant secondary metabolites, especially phenylpropanoid and flavonoid compounds. An OMT, ROMT-9, was cloned and characterized from rice using a reverse transcriptase polymerase chain reaction (RT-PCR). The blast results for ROMT-9 showed a 73% identity with caffeic acid OMTs from maize and Triticum aestivum. ROMT-9 was expressed in Escherichia coli and its recombinant protein was purified using affinity chromatography. It was then tested for its ability to transfer the methyl group of S-adenosyl-l-methionine to the flavonoid substrates, eriodictyol, luteolin, quercetin, and taxifolin, all of which have a 3′-hydroxyl functional group. The reaction products were analyzed using TLC, HPLC, HPLC/MS, and NMR spectroscopy. The NMR analysis showed that ROMT-9 transferred the methyl group specifically to the 3′-hydroxyl group of quercetin, resulting in the formation of its methoxy derivative. Furthermore, ROMT-9 converted flavonoids containing the 3′-hydroxy functional group such as eriodictyol, luteolin, quercetin and taxifolin into the corresponding methoxy derivatives, suggesting that ROMT-9 is an OMT with strict specificity for the 3′-hydroxy group of flavonoids.
- Kim, Bong-Gyu,Lee, Youngshim,Hur, Hor-Gil,Lim, Yoongho,Ahn, Joong-Hoon
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p. 387 - 394
(2008/02/04)
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- Compositions and methods of use of derivatized flavanols
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The invention relates to compositions containing derivatized flavanols such as methylated flavanols, and methods of use thereof for prophylactic or therapeutic treatment of a human or a veterinary animal for example as anti-platelet agents.
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Page/Page column 5; 6
(2008/06/13)
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- An efficient synthesis of the four mono methylated isomers of (+)-catechin including the major metabolites and of some dimethylated and trimethylated analogues through selective protection of the catechol ring
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The four monomethylated isomers of (+)-catechin in positions 3′, 4′, 5 and 7, two dimethylated derivatives, the 5,7-dimethylcatechin and the 3′, 4′-dimethylcatechin and two trimethylated isomers of (+)-catechin in positions 3′, 5, 7 and 4′, 5, 7 were synthesized by a new method based on successive and selective protections of the various phenol functions present on (+)-catechin. The key step was the selective protection of the catechol ring with dichlorodiphenylmethane and di-tert-butyldichlorosilane.
- Cren-Olive, Cecile,Lebrun, Stephane,Rolando, Christian
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p. 821 - 830
(2007/10/03)
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- Symplocoside, a flavanol glycoside from Symplocos uniflora
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A new flavanol glycoside, symplocoside, was isolated from the MeOH extract of the stem bark of Symplocos uniflora and its constitution and conformation were elucidated by means of MS, 1H and 13C NMR spectroscopy as (2R:3R)-7-O-β-D-glucopyranosyl-3′-O-methyl-(-)-epicatechin.
- Tschesche,Braun,Sassen
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p. 1825 - 1829
(2007/12/18)
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