41743-41-3Relevant academic research and scientific papers
Syntheses of doubly linked proanthocyanidins using free flavan units as nucleophiles: Insight into the origin of the high regioselectivity of annulation
Betkekar, Vipul V.,Harachi, Mio,Suzuki, Keisuke,Ohmori, Ken
supporting information, p. 9129 - 9134 (2019/11/05)
A synthesis method of doubly linked flavan dimers is reported via the acid-promoted annulation reaction using nascent catechins, (+)-catechin or (-)-epicatechin, as a dianionic partner and an ethylenedioxy-bridged flavan as a dicationic partner. Procyanidins A1 and A2 were synthesized. On the high regioselectivity of the annulation reactions, model experiments and computational studies were carried out.
Anticancer activities of proanthocyanidins from the plant Urceola huaitingii and their synergistic effects in combination with chemotherapeutics
Yu, Ru-Jian,Liu, Hai-Bin,Yu, Yang,Liang, Lu,Xu, Rui,Liang, Chun,Tang, Jin-Shan,Yao, Xin-Sheng
, p. 175 - 182 (2016/07/06)
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.
Total Synthesis of Proanthocyanidin A1, A2, and Their Stereoisomers
Sharma, Pradeep K.,Romanczyk, Leo J.,Kondaveti, Leelakrishna,Reddy, Bollu,Arumugasamy, Jeeva,Lombardy, Richard,Gou, Yanni,Schroeter, Hagen
supporting information, p. 2306 - 2309 (2015/05/27)
The first novel stereoselective synthesis of naturally occurring A1 (1) and A2 proanthocyanidins (2) has been achieved. The key synthetic steps involved (a) the formation of a coupled product (13 or 14) between an open chain C-ring C-4 hydroxyethoxy analo
Annulation approach to doubly linked (A-type) oligocatechins: Syntheses of (+)-procyanidin A2 and (+)-cinnamtannin B1
Ito, Yuji,Ohmori, Ken,Suzuki, Keisuke
supporting information, p. 10129 - 10133 (2015/03/31)
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
Polyphenols from peanut skins and their free radical-scavenging effects
Lou, Hongxiang,Yuan, Huiqing,Ma, Bin,Ren, Dongmei,Ji, Mei,Oka, Syuichi
, p. 2391 - 2399 (2007/10/03)
Separation of the water-soluble fraction of peanut skins led to the isolation of five proanthocyanidins. Based on the spectroscopic investigation and partial acid catalyzed degradation, their structures were determined to be epicatechin-(2β→O→7, 4β→6)-[epicatechin- (4β→8)]-catechin (1), epicatechin-(2β→O→7, 4β→8) epicatechin-(4β→8)-catechin-(4β→8)- epicatechin (2), and procyanidins B2 (3), B3 (4) and B4 (5). The absolute configuration of the new compounds was determined from their circular dichroism curves and the 1H NMR spectra of analysis of flavan-3-ols formed by thiolytic degradation of 1 and 2 in the presence of a chiral dirhodium complex (dirhodium tetra-(R)-(trifluoromethyl) phenyl acetate).
Conversion of procyanidin B-type (catechin dimer) to A-type: Evidence for abstraction of C-2 hydrogen in catechin during radical oxidation
Kondo, Kazunari,Kurihara, Masaaki,Fukuhara, Kiyoshi,Tanaka, Takashi,Suzuki, Takashi,Miyata, Naoki,Toyoda, Masatake
, p. 485 - 488 (2007/10/03)
Procyanidin B-1 and B-2 were converted into A-1 and A-2 by radical oxidation using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals under neutral conditions, respectively. Transformation of procyanidin B-type into A-type certainly shows abstraction of the hy
DIMERIC AND TRIMERIC PROANTHOCYANIDINS POSSESSING A DOUBLY LINKED STRUCTURE FROM PAVETTA OWARIENSIS
Balde, A. M.,Pieters, L. A.,Wray, V.,Kolodziej, H.,Berghe, D. A. Vanden,et al.
, p. 4129 - 4136 (2007/10/02)
Pavetannin A-2, a new A-type proanthocyanidin, along with the trimers cinnamtannin B-1, pavetannin B-1, B-2, B-3, B-5 and B-6 have been isolated in their free phenolic form from the stem bark of Pavetta owariensis.Spectral data and partial acid-catalysed degradation established their structures as ent-epicatechin-(4α->8,2α->O->7)-catechin, epicatechin-(4β->8,2β->O->7)-epicatechin-(4α->8)-epicatechin, epicatechin-(4β->8,2β->O->7)-epicatechin-(4β->8)-ent-epicatechin, epicatechin-(4β->8,2β->O->7)-epicatechin-(4β->8)-epicatechin, epicatechin-(4β->6,2β->O->7)-epicatechin-(4β->8)-epicatechin, epicatechin-(4β->6,2β->O->7)-catechin-(4β->8)-epicatechin, epicatechin-(4β->8,2β->O->7)-epicatechin-(4α->8)-catechin, respectively. Key Word Index - Pavetta owariensis; Rubiaceae; stem bark; proanthocyanidins; doubly linked structures; dimer; trimer; thiolytic degradation.
Tannins and Related Compounds. LIX. Aesculitannins, Novel Proanthocyanidins with Doubly-Bonded Structures from Aesculus hippocastanum L.
Morimoto, Satoshi,Nonaka, Gen-ichiro,Nishioka, Itsuo
, p. 4717 - 4729 (2007/10/02)
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
Tannins and Related Compounds. Part 13. Isolation and Structures of Trimeric, Tetrameric, and Pentameric Proanthicyanidins from Cinnamon
Nonaka, Gen-ichiro,Morimoto, Satoshi,Nishioka, Itsuo
, p. 2139 - 2145 (2007/10/02)
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).
