- Synthesis of novel (?)-epicatechin derivatives as potential endothelial GPER agonists: Evaluation of biological effects
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To potentially identify proteins that interact (i.e. bind) and may contribute to mediate (?)-epicatechin (Epi) responses in endothelial cells we implemented the following strategy: 1) synthesis of novel Epi derivatives amenable to affinity column use, 2)
- Sarmiento, Viviana,Ramirez-Sanchez, Israel,Moreno-Ulloa, Aldo,Romero-Perez, Diego,Chávez, Daniel,Ortiz, Miguel,Najera, Nayelli,Correa-Basurto, Jose,Villarreal, Francisco,Ceballos, Guillermo
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- Asymmetric total synthesis of talienbisflavan A
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The first asymmetric total syntheses of talienbisflavan A and bis-8,8′-epicatechinylmethane as well as a facile synthesis of bis-8,8′-catechinylmethane has been accomplished from readily available starting materials by using a newly developed direct regio
- Huang, Deng-Ming,Li, Hui-Jing,Wang, Jun-Hu,Wu, Yan-Chao
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p. 585 - 592
(2018/02/07)
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- NOVEL ANALOGUES OF EPICATECHIN AND RELATED POLYPHENOLS
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The present invention provides novel analogues of epicatechin and related polyphenols, their variously functionalized derivatives, process for preparation of the same, composition comprising these compounds and their method of use.
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Paragraph 0283; 0284
(2016/03/05)
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- Towards the discovery of drug-like epigallocatechin gallate analogs as Hsp90 inhibitors
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(-)-Epigallocatechin gallate (EGCG) is the major flavonoid of green tea and has been widely explored for a range of biological activities including anti-infective, anti-inflammatory, anti-cancer, and neuroprotection. Existing structure-activity data for EGCG has been largely limited to exploration of simple ethers and hydroxyl deletion. EGCG has poor drug-like properties because of multiple phenolic hydroxyl moieties and a metabolically labile ester. This work reports a substantial expansion of structure-activity understanding by exploring a range of semi-synthetic and synthetic derivatives with ester replacements and variously substituted aromatic and alicyclic groups containing more drug-like substituents. Structure-activity relationships for these molecules were obtained for Hsp90 inhibition. The results indicate that amide and sulfonamide linkers are suitable ester replacements. Hydroxylated aromatic rings and the cis-stereochemistry in EGCG are not essential for Hsp90 inhibition. Selected analogs in this series are more potent than EGCG in a luciferase refolding assay for Hsp90 activity.
- Bhat, Rohit,Adam, Amna T.,Lee, Jungeun Jasmine,Gasiewicz, Thomas A.,Henry, Ellen C.,Rotella, David P.
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p. 2263 - 2266
(2014/05/20)
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- Design, synthesis and characterization of novel inhibitors against mycobacterial β-ketoacyl CoA reductase FabG4
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We report the design and synthesis of triazole-polyphenol hybrid compounds 1 and 2 as inhibitors of the FabG4 (Rv0242c) enzyme of Mycobacterium tuberculosis for the first time. A major advance in this field occurred only a couple of years ago with the X-ray crystal structure of FabG4, which has helped us to design these inhibitors by the computational fragment-based drug design (FBDD) approach. Compound 1 has shown competitive inhibition with an inhibition constant (Ki) value of 3.97 ± 0.02 μM. On the other hand, compound 2 has been found to be a mixed type inhibitor with a Ki value of 0.88 ± 0.01 μM. Thermodynamic analysis using isothermal titration calorimetry (ITC) reveals that both inhibitors bind at the NADH co-factor binding domain. Their MIC values, as determined by resazurin assay against M. smegmatis, indicated their good anti-mycobacterial properties. A preliminary structure-activity relationship (SAR) study supports the design of these inhibitors. These compounds may be possible candidates as lead compounds for alternate anti-tubercular drugs. All of the reductase enzymes of the Mycobacterium family have a similar ketoacyl reductase (KAR) domain. Hence, this work may be extrapolated to find structure-based inhibitors of other reductase enzymes. The Royal Society of Chemistry.
- Banerjee, Deb Ranjan,Dutta, Debajyoti,Saha, Baisakhee,Bhattacharyya, Sudipta,Senapati, Kalyan,Das, Amit K.,Basak, Amit
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- NOVEL PROCESS FOR SYNTHESIS OF POLYPHENOLS
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The present invention provides synthetic processes for preparing racemic and/or optically pure epicatechin, epigallocatechin and related polyphenols as such or as their variously functionalized derivatives. A principle objective of the disclosure is to provide a new and useful method of synthesis to obtain polyphenols in isomerically pure and/or racemic forms.
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- Factors influencing the antifolate activity of synthetic tea-derived catechins
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Novel tea catechin derivatives have been synthesized, and a structure-activity study, related to the capacity of these and other polyphenols to bind dihydrofolate reductase (DHFR), has been performed. The data showed an effective binding between all molecules and the free enzyme, and the dissociation constants of the synthetic compounds and of the natural analogues were on the same order. Polyphenols with a catechin configuration were better DHFR inhibitors than those with an epicatechin configuration. Antiproliferative activity was also studied in cultured tumour cells, and the data showed that the activity of the novel derivatives was higher in catechin isomers. Derivatives with a hydroxyl group para on the ester-bonded gallate moiety presented a high in vitro binding to DHFR, but exhibited transport problems in cell culture due to ionization at physiologic pHs. The impact of the binding of catechins to serum albumin on their biological activity was also evaluated. The information provided in this study could be important for the design of novel medicinal active compounds derived from tea catechins. The data suggest that changes in their structure to avoid serum albumin interactions and to facilitate plasmatic membrane transport are essential for the intracellular functions of catechins.
- Saez-Ayala, Magali,Fernandez-Perez, Maria Piedad,Chazarra, Soledad,McHedlishvili, Nani,Tarraga-Tomas, Alberto,Rodriguez-Lopez, Jose Neptuno
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p. 8319 - 8341
(2013/08/23)
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- A new synthetic strategy for catechin-class polyphenols: Concise synthesis of (-)-epicatechin and its 3-O-gallate
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Concise synthesis of (-)-epicatechin and its 3-O-gallate is described, illustrating efficacy of the new strategy for catechin-class polyphenols based on assembly of lithiated fluorobenzene and epoxy alcohol followed by a pyran cyclization. 1,3,5-Trifluorobenzene serves as the A-ring equivalent for functionalization and the pyran annulation.
- Stadlbauer, Sven,Ohmori, Ken,Hattori, Fumihiko,Suzuki, Keisuke
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supporting information
p. 8425 - 8427
(2012/10/29)
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- A NOVEL PROCESS FOR SYNTHESIS OF POLYPHENOLS
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The present invention provides synthetic processes for preparing racemic and/or optically pure epicatechin, epigallocatechin and related polyphenols as such or as their variously functionalized derivatives.
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- Comparison of a Pair of Synthetic Tea-Catechin-Derived Epimers: Synthesis, Antifolate Activity, and Tyrosinase-Mediated Activation in Melanoma
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Despite bioavailability issues, tea catechins have emerged as promising chemopreventive agents because of their efficacy in various animal models. We synthesized two catechin-derived compounds, 3-O-(3,4,5-trimethoxybenzoyl)-(-)-catechin (TMCG) and 3-O-(3,4,5-trimethoxybenzoyl)-(-)-epicatechin (TMECG), in an attempt to improve the stability and cellular absorption of tea polyphenols. The antiproliferative and pro-apoptotic activities of both compounds were analyzed with various cancer cell systems, and TMCG, which was easily synthesized in excellent yield, was more active than TMECG in both melanoma and non-melanoma cell lines. TMCG was also a better inhibitor of dihydrofolate reductase and was more efficiently oxidized by tyrosinase, potentially explaining the difference in activity between these epimers.
- Saez-Ayala, Magali,Sanchez-Del-Campo, Luis,Montenegro, Maria F.,Chazarra, Soledad,Tarraga, Alberto,Cabezas-Herrera, Juan,Rodriguez-Lopez, Jose Neptuno
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p. 440 - 449
(2012/01/06)
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- General synthesis of epi-series catechins and their 3-gallates: Reverse polarity strategy
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A general synthetic route to the epi-series catechins was developed based on the reverse polarity strategy. Aromatic nucleophilic substitution reaction followed by the sulfinyl-metal exchange and cyclization enabled stereo-controlled access to various members of epi-series catechins and their 3-gallates.
- Ohmori, Ken,Yano, Takahisa,Suzuki, Keisuke
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supporting information; experimental part
p. 2693 - 2696
(2010/08/21)
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- Total synthesis of 14C-labeled procyanidin B2
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During the last decades, many in vitro and in vivo studies have shown the beneficial effects on health of procyanidins. However, their absorption and metabolism is still not fully understood and some aspects are still controversial. In order to have a clearer picture of the metabolism of procyanidins, the use of labelled compounds is essential. In this context, the enantioselective synthesis of 14C-radiolabelled procyanidin B2 was developed in our laboratories. It was achieved in fourteen 'hot' steps, involving as key steps the Sharpless dihydroxylation of an elaborated alkene, a stereoselective intramolecular cyclization to benzylated (+)-catechin and the condensation of two (-)-epicatechin units. 11 mCi of protected procyanidin B2 were obtained from 524 mCi of potassium [14C]cyanide. Copyright
- Viton, Florian,Landreau, Cyrille,Rustidge, David,Little, Gill,Robert, Fabien,Williamson, Gary,Barron, Denis
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p. 371 - 374
(2011/05/05)
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- Synthesis and ribonuclease A inhibition activity of resorcinol and phloroglucinol derivatives of catechin and epicatechin: Importance of hydroxyl groups
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The reported ribonuclease A inhibitory activity of the green tea extracts prompted us to synthesize novel catechin/epicatechin based conjugates with resorcinol and phloroglucinol with the aim to increase the number of phenolic OH groups. These are found to be more effective inhibitors of ribonuclease A as compared to catechin and epicatechin thus indicating the importance of number of phenolic OH groups for the inhibition of ribonucleolytic activity. Fluorescence studies have been carried out to evaluate the binding parameters. The protein-ligand docking studies are also performed to gain insight into the protein-polyphenols interactions. The epicatechin based polyphenols 1 and 2 also showed inhibition of angiogenin-induced angiogenesis, as determined by chorioallantoic membrane (CAM) assay.
- Dutta, Sansa,Basak, Amit,Dasgupta, Swagata
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scheme or table
p. 6538 - 6546
(2010/10/03)
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- Synthesis of procyanidins by stepwise- and self-condensation using 3,4-cis-4-acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-ben zyl-(+)-catechin and (-)-epicatechin as a key building monomer
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3,4-cis-4-Acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-ben zyl-(+)-catechin (1a) or (-)-epicatechin (1b) reacted high regio- and stereo-selectively with 1.5 equiv of the 5,7,3′,4′-tetra-O-benzyloxyflavan-3-ol (4a or 4b) in the presence of 1 equiv of TMSOTf to give the corresponding procyanidins. On the other hand, the self-condensation of 1a in the presence of a catalytic amount of B(C6F5)3 afforded wide-range procyanidins from dimer to 15-mer like a biomass.
- Oyama, Kin-ichi,Kuwano, Miyuki,Ito, Mie,Yoshida, Kumi,Kondo, Tadao
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p. 3176 - 3180
(2008/09/20)
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- First total synthesis of14C-labeled procyanidin B2 - A milestone toward understanding cocoa polyphenol metabolism
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The idea that foods consumed for pure pleasure could provide health benefits received much recognition in the recent years. Among these foods, cocoa and dark chocolate are particularly rich in procyanidins, one of the major dietary families of polyphenols. We developed the first asymmetric total synthesis of procyanidin B2 and applied it to the preparation of a regioselectively radiolabeled 14C-analogue, which will be used to strengthen our knowledge on the metabolism of procyanidins. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Viton, Florian,Landreau, Cyrille,Rustidge, David,Robert, Fabien,Williamson, Gary,Barron, Denis
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supporting information; scheme or table
p. 6069 - 6078
(2009/05/27)
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- Scale-Up Syntheses of Two Naturally Occurring Procyanidins: (-)-Epicatechin-(4β,8)-(+)-catechin and (-)-Epicatechin-3-0-galloyl- (4β, 8)-(-)-epicatechin-3-0-gallate
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A scaleable process for the synthesis of two naturally occurring procyanidins, namely (-)-epicatechin-(4β,8)-(+)-catechin (1) and(-)-epiratechin-3-O-galloyl-(4β,8)-(-)-epicatechin-3-O-gallate (2), is described. The key steps were highlighted by improvements for the benzylation of (+)-catechin (3), stereo-selective reduction of the C-3 keto group of (2A)-5,7,3′,4′-tetrakis(benzyloxy)flavan-3-one (10), and coupling between 4-hydroxyethoxy-5,7,3′,4′-tetra-O-benzyl-(-)-epicatechin (11) and 5,7,3′,4′-tetra-O-benzyl-(+)-catechin (4) or 5,7,3′,4′-tetra-O-benzyl-(-)-epicatechin (6), respectively. The debenzylation performed in a biphasic system resulted in an improved yield and purity of the target compounds. The chemistry was scaled-up to produce multigram quantities of the title compounds (1 and 2) for various in vitro, ex vivo, and in vivo studies. Moreover, the scale-up process provided a detailed description for the preparation of multihundred to kilogram scale quantities of intermediates used in the synthesis of these two titled procyanidins.
- Sharma, Pradeep K.,Kolchinski, Alexander,Shea, Helene A.,Nair, Jayesh J.,Gou, Yanni,Romanczyk Jr., Leo J.,Schmitz, Harold H.
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p. 422 - 430
(2012/12/31)
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- Epicatechin conjugated with fatty acid is a potent inhibitor of DNA polymerase and angiogenesis
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Anti-cancer and anti-angiogenesis effects of green tea catechins have been demonstrated. It has been found that chemical modification of tea catechins improves their biological activities. We examined the chemical modification of epicatechin enhanced anti
- Matsubara, Kiminori,Saito, Akiko,Tanaka, Akira,Nakajima, Noriyuki,Akagi, Reiko,Mori, Masaharu,Mizushina, Yoshiyuki
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p. 1578 - 1585
(2008/02/02)
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- An improved synthesis of procyanidin dimers: Regio- and stereocontrol of the interflavan bond
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A direct and general synthesis of procyanidin dimers B1, B2, B3 and B4 (10a-d) is presented. The approach is based on the stoichiometric coupling of two protected monomeric units (the nucleophilic 2a-b and electrophilic 4a-b partners) and deals with the regio- and stereocontrol of the C4-C8 interflavan bond as well as the control of the degree of oligomerization. The synthesis involves a five-step pathway starting from the native catechin (1a) or epicatechin (1b) to the fully deprotected dimers 10a-d. Furthermore, the process appears to be iterative as the coupling intermediates 9a-d themselves can be readily used in further selective syntheses of trimers or higher oligomers. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Tarascou, Isabelle,Barathieu, Karine,Andre, Yann,Pianet, Isabelle,Dufourc, Erick J.,Fouquet, Eric
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p. 5367 - 5377
(2007/10/03)
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- ISOLATION, PURIFICATION AND SYNTHESIS OF PROCYANIDIN B2 AND USES THEREOF
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Methods for the synthesis, isolation, and purification of procyanidin B2 are disclosed. The synthetic methods utilize epicatechin as a starting material and produce procyanidin BZ in high yields. The isolation methods extract procyanidin B2 from a sample of bark powder from plant matter of the genus Uncaria. The isolated and/or synthesized procyanidin B2 is used to treat amyloid disease, such as Alzheimer's disease and Parkinson's disease. Pharmaceutical compositions containing the synthesized and/or isolated procyanidin B2 are also disclosed.
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- Anticancer activity of 3-O-acyl and alkyl-(-)-epicatechin derivatives
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We report the synthesis and anticancer effects of 3-O-acyl and alkyl-(-)-epicatechin derivatives.
- Park, Ki Duk,Lee, Sul Gi,Kim, Sung Uk,Kim, Sung Han,Sun, Won Suck,Cho, Sung Jin,Jeong, Do Hyeon
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p. 5189 - 5192
(2007/10/03)
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- Study of the green tea polyphenols catechin-3-gallate (CG) and epicatechin-3-gallate (ECG) as proteasome inhibitors
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The green tea polyphenol catechin-3-gallate (CG) and epicatechin-3-gallate (ECG) were synthesized enantioselectively via a Sharpless hydroxylation reaction followed by a diastereoselective cyclization. Their potencies to inhibit the proteasome activity were measured. The unnatural enantiomers were found to be equally potent to the natural compounds.
- Wan, Sheng Biao,Chen, Di,Dou, Q. Ping,Chan, Tak Hang
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p. 3521 - 3527
(2007/10/03)
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- Studies in polyphenol chemistry and bioactivity. 1. Preparation of building blocks from (+)-catechin. Procyanidin formation. Synthesis of the cancer cell growth inhibitor, 3-O-galloyl-(2R,3R)-epicatechin-4β,8-[3-O-galloyl-(2R,3R)-epicatechin]
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A project has been initiated to synthesize proanthocyanidin oligomers found in cocoa. Natural, readily available (+)-catechin was transformed into 5,7,3′,4′-tetra-O-benzyl-(-)-epicatechin (14) by (a) benzylation of the phenolic oxygens; (b) oxidation of the 3-alcohol to ketone by the Dess-Martin periodinane; and (c) reduction with lithium tri-sec-butylborohydride (L-Selectride) in the presence of LiBr. The additive diminishes the extent of ketone enolization while maintaining a stereoselectivity of ≥ 200:1. Oxidation of 14 with DDQ was performed best from the standpoint of product purification if ethylene glycol was used as the nucleophilic trapping agent. The resulting ether 19 was condensed with 14 using TiCl4 to give a good yield of benzyl-protected epicatechin-4β,8-epicatechin (octa-O-benzylprocyanidin B2, 20) as the sole dimeric product. Hydrogenolysis of 20 yielded procyanidin B2 in the first enantiospecific synthesis of this natural product which employs protected intermediates and thereby allows the necessary product separation after the condensation step to be performed on nonpolar, nonsensitive intermediates. Acylation of 20 with tri-O-benzylgalloyl chloride followed by hydrogenolysis gave access to the title bis-gallate (24). This constitutes the first synthesis of this natural product, a compound notable for its PKC-inhibitory and anticancer activity.
- Tueckmantel, Werner,Kozikowski, Alan P.,Romanczyk Jr., Leo J.
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p. 12073 - 12081
(2007/10/03)
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