- Proanthocyanidin Tetramers and Pentamers from Cinnamomum verum Bark and Their Dentin Biomodification Bioactivities
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To enable the further exploration of structure-activity relationships (SARs) of proanthocyanidins (PACs) with dentin biomodification abilities, Cinnamomum verum was selected for scaled-up purification of mixed A-/B-type, medium-size PAC oligomers. Sequential purification by centrifugal partition chromatography (CPC), Sephadex LH-20, and semiprep HPLC chromatography yielded four underivatized tetrameric (5-8) and two pentameric (9-10) PACs. Their unambiguous structural characterization involved extensive spectral and chemical degradation approaches to show that epicatechin units are connected by plant-specific combinations of doubly linked A- and singly linked B-type interflavanyl bonds. The biomechanical properties (via dynamic mechanical analysis) and physicochemical structure (via infrared spectroscopy) were assessed to evaluate the biomodification potency of PAC-treated collagen in a preclinical dentin model. This study revealed that (4→8) versus (4→6) bonds in PAC interflavan linkages have limited influence on biomechanical outcomes of dentin. By exhibiting a 25-fold increase in the complex modulus of treated dentin compared to control, aesculitannin E (5) was found to be the most potent PAC known to date for enhancing the mechanical properties of dentin in this preclinical model.
- Jing, Shu-Xi,Alania, Yvette,Reis, Mariana,McAlpine, James B.,Chen, Shao-Nong,Bedran-Russo, Ana K.,Pauli, Guido F.
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p. 391 - 404
(2022/02/16)
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- Anticancer activities of proanthocyanidins from the plant Urceola huaitingii and their synergistic effects in combination with chemotherapeutics
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Phytochemical investigation of the stem of Urceola huaitingii resulted in the isolation of nine proanthocyanidins (1-9), including a new compound (9). Their chemical structures were determined by UV, (HR) ESI-MS, 1D-, 2D-NMR, and CD spectra in combination with chemical derivatization. Determination of the absolute configuration of proanthocyanidins were discussed, which suggested that positive Δ? values at 245 nm can be applied to determine the absolute configuration of them. In addition, anticancer activities of proanthocyanidins (1-9) and their synergistic anticancer effects in combination with chemotherapeutics were evaluated. The results showed that some proanthocyanidins, especially compound 7 possessing two doubly interflavonoid linkages, exhibited significant synergistic anticancer effects with some chemotherapeutics in multiple cancer cell lines.
- Yu, Ru-Jian,Liu, Hai-Bin,Yu, Yang,Liang, Lu,Xu, Rui,Liang, Chun,Tang, Jin-Shan,Yao, Xin-Sheng
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p. 175 - 182
(2016/07/06)
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- Annulation approach to doubly linked (A-type) oligocatechins: Syntheses of (+)-procyanidin A2 and (+)-cinnamtannin B1
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The first stereoselective syntheses of doubly linked (A-type) oligocatechins, (+)-procyanidin A2 and (+)-cinnamtannin B1, have been achieved. Ethylenedioxy-bridged flavans served as excellent platforms, thus allowing annulation with
- Ito, Yuji,Ohmori, Ken,Suzuki, Keisuke
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supporting information
p. 10129 - 10133
(2015/03/31)
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- Studies on the constituents of bark of Parameria laevigata Moldenke
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One new trimeric proanthocyanidin, epicatechin-(2β→O→7,4β→6)-epicatechin- (2β→O→7, 4β→8)epicatechin (5) and two new tetrameric proanthocyanidins, epicatechin-(2β→O→7, 4β→8)-[epicatechin-(4β6)]epicatechin-(4β→8)- epicatechin, named as parameritannin A-1 (6), and epicatechin-(2β→O→5, 4β→6)[epicatechin-(2β→O→7, 4β→8)]-epicatechin-(4β→8)-epicatechin, named as parameritannin A-2 (7), have been isolated from the bark of Parameria laevigata Moldenke (Apocynaceae) along with the two known dimers, proanthocyanidin A-2 (1) and proanthocyanidin A-6 (2), and two dimers, cinnamtannin B-1 (3) and aesculitannin B (4). These structures were elucidated by spectral and chemical evidence.
- Kamiya,Watanabe,Endang,Umar,Satake
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p. 551 - 557
(2007/10/03)
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- Tannins and Related Compounds. LIX. Aesculitannins, Novel Proanthocyanidins with Doubly-Bonded Structures from Aesculus hippocastanum L.
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A chemical examination of the seed shells of Aesculus hyppocastanum L.has led to the isolation of proanthocyanidins A-6 (10) and A-7 (11), and aesculitannins A (12), B (13), C (14), D (15), E (16), F (17) and G (18).On the basis of chemical and spectroscopic evidence, proanthocyanidins A-6 (10) and A-7 (11) have been determined to be A-type dimers each possessing a C-4, C-6 interflavanoid linkage, while aesculitannins A (12), B (13), C (14), D (15), E (16), F (17) and G (18) have been characterized as oligomeric proanthocyanidins possessing A-type unit(s) in each molecule.In addition, the presence of (-)-epicatechin (1), proanthocyanidins B-5 (3), A-2 (4), A-4 (5) and C-1 (6), epicatechin-(4β->6)-epicatechin-(4β->6)-epicatechin (7), and cinnamtannins B1 (8) and B2 (9) was also demonstrated Keywords---Aesculus hippocastanum; Hippocastanaceae; aesculitannin; doubly-bonded proanthocyanidin; procyanidin; condensed tannin; flavan-3-ol; thiolytic degradation; epimerization; hydrogen peroxide oxidation
- Morimoto, Satoshi,Nonaka, Gen-ichiro,Nishioka, Itsuo
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p. 4717 - 4729
(2007/10/02)
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- Tannins and Related Compounds. Part 13. Isolation and Structures of Trimeric, Tetrameric, and Pentameric Proanthicyanidins from Cinnamon
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A proanthocyanidin trimer, two tetramers, and a pentamer have been isolated in their free phenolic forms from cinnamon, the bark of Cinnamomum zeylanicum (Lauraceae).Partial acid-catalysed degradation of these tannins with phenylmethanethiol, in conjunction with 1H- and 13C-n.m.r. analysis, has unequivocally established their structures as epicatechin-(4β->8, 2β->7)epicatechin-(4α->8)-epicatechin (5); epicatechin-(4β->8)epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (6); epicatechin-(4β->6)-epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (7); and epicatechin-(4β->8)-epicatechin-(4β->8)epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (8).
- Nonaka, Gen-ichiro,Morimoto, Satoshi,Nishioka, Itsuo
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p. 2139 - 2145
(2007/10/02)
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