- Synthesis of galloyl-substituted procyanidin B4 series, and their DPPH radical scavenging activity and DNA polymerase inhibitory activity
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Synthesis of galloyl-substituted procyanidin B4 series, 3-O-gallate, 3″-O-gallate and 3,3″-di-O-gallate, is described. Condensationof the electrophile derived from (+)-catechin with the nucleophile derived from (-)-epicatechin the presence of TMSOTf as a
- Sakuda, Hironori,Saito, Akiko,Mizushina, Yoshiyuki,Yoshida, Hiromi,Tanaka, Akira,Nakajima, Noriyuki
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- Syntheses of procyanidin B2 and B3 gallate derivatives using equimolar condensation mediated by Yb(OTf)3 and their antitumor activities
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Synthesis of procyanidin B2 and B3 gallate derivatives, 3-O-gallate, 3″-O-gallate, and 3,3″-di-O-gallate, were synthesized using equimolar condensation mediated by Yb(OTf)3. Synthesized compounds showed significant antitumor effects against human prostate PC-3 cell lines. Their activities were weaker than well-known EGCG and prodelphinidin B3.
- Suda, Manato,Katoh, Miyuki,Toda, Kazuya,Matsumoto, Kiriko,Kawaguchi, Koichiro,Kawahara, Sei-Ichi,Hattori, Yasunao,Fujii, Hiroshi,Makabe, Hidefumi
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p. 4935 - 4939
(2013/09/02)
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- Processes for the preparation of protected-(+)-catechin and (-)-epicatechin monomers, for coupling the protected monomers with an activated, protected epicatechin monomer, and for the preparation of epicatechin-(4B,8)-epicatechin or -catechin dimers and their digallates
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Improved processes for the preparation of tetra-O-benzyl protected catechin, for the coupling of the tetra-O-benzyl protected catechin or epicatechin with a C-4 activated, tetra-O-benzyl protected epicatechin for the galloylation of the epicatechin-(4β,8)-catechin or -epicatechin dimer-the dimer digallates, and for the deprotection (i.e., debenzylation) of the protected epicatechin dimers and protected epicatechin dimer digallates are disclosed.
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Page/Page column 7
(2010/11/25)
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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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- Systematic synthesis of galloyl-substituted procyanidin B1 and B2, and their ability of DPPH radical scavenging activity and inhibitory activity of DNA polymerases
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Six galloyl-substituted procyanidin B1 and B2, 3-O-gallate, 3″-O-gallate, and 3,3″-di-O-gallate, were systematically synthesized with the condensation method using TMSOTf as a catalyst. Their ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity were also investigated. The results indicated that the galloyl group of these compounds is very important for both activities. 3,3″-Di-O-gallate dimers acted as strong inhibitor against DNA polymerase α and β, whereas the desgalloyl and monogalloyl compounds did not exhibit any appreciable inhibitory activity against the DNA polymerase β.
- Saito, Akiko,Mizushina, Yoshiyuki,Ikawa, Hiroshi,Yoshida, Hiromi,Doi, Yuki,Tanaka, Akira,Nakajima, Noriyuki
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p. 2759 - 2771
(2007/10/03)
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- Compositions and methods of use of dimer digallates
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The invention relates to compositions, such as pharmaceuticals, foods, food additives, or dietary supplements, containing dimer digallates, and methods of use thereof, for prophylactic or therapeutic treatment of a human or a veterinary animal to treat or prevent NO-responsive health conditions, treat hypertension, cardiovascular disease, coronary artery disease, diabetes, cognitive dysfunction or disorder and/or vascular circulation disorders, prevent or reduce the risk of heart attack, stroke, congestive heart failure and/or kidney failure, or to improve blood flow, for example renal blood flow. The composition may optionally contain an additional NO modulating agent and/or a vascular-protective or therapeutic agent, or may be administered in combination with such an agent.
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Page/Page column 13-14
(2010/02/15)
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- Stereoselective synthesis of procyanidin B3-3-O-gallate and 3,3″-di-O-gallate, and their abilities as antioxidant and DNA polymerase inhibitor
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A simple method for the synthesis of procyanidin B3 substituted with a galloyl group at the 3 and 3″ position is described. Condensation of a benzylated catechin-3-O-gallate electrophile with a nucleophile, catechin and catechin-3-O-gallate, proceeded smoothly and stereoselectively to afford the corresponding dimer gallates, procyanidin B3-3-O-gallate and procyanidin B3-3,3″-di-O-gallate, in good yields. Further, their antioxidant activities on UV-induced lipid peroxide formation, DPPH radical scavenging activity and inhibitory activity of DNA polymerase were also investigated. Among three procyanidin B3 congeners (procyanidin B3, 3-O-gallate and 3,3″-di-O-gallate), the 3,3″-di-O-gallate derivative showed the strongest antioxidant and radical scavenging activity. Interestingly, the 3-O-gallate derivative was the strongest inhibitor of mammalian DNA polymerase α with IC50 value of 0.26 μM, although it showed the weakest antioxidant and radical scavenging activity. It became apparent that the presence of a galloyl group at the C-3 position in the proanthocyanidin oligomer was very important for biological activity, however, the antioxidant activity of these compounds was not parallel to the DNA polymerase inhibitory activity. Graphical Abstract
- Saito, Akiko,Emoto, Mana,Tanaka, Akira,Doi, Yuki,Shoji, Kazuaki,Mizushina, Yoshiyuki,Ikawa, Hiroshi,Yoshida, Hiromi,Matsuura, Nobuyasu,Nakajima, Noriyuki
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p. 12043 - 12049
(2007/10/03)
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- Synthetic methods for preparation of protected proanthocyanidin(s)
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A process is disclosed for the production of polyphenol oligomers having n polyphenol monomeric units, n being an integer from 2-18. The process includes coupling of a protected polyphenol, having protected phenolic hydroxyl groups, with a C-4 functionali
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