50562-99-7Relevant articles and documents
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 (1991)
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.
Studies on the constituents of bark of Parameria laevigata Moldenke
Kamiya,Watanabe,Endang,Umar,Satake
, p. 551 - 557 (2007/10/03)
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.
Tannins and Related Compounds. LX. Isolation and Characterization of Proanthocyanidins with a Doubly-Linked Unit from Vaccinium vitis-idaea L.
Morimoto, Satoshi,Nonaka, Gen-Ichiro,Nishioka, Itsuo
, p. 33 - 38 (2007/10/02)
New proanthocyanidin trimers (14 and 15) and tetramers (16 and 17) have been isolated from the whole body of Vaccinium vitis-idaea L. (Ericaceae).The structures of these proanthocyanidins were established by thiolytic degradation and by analyses of the proton and carbon-13 nuclear magnetic resonance spectra.In addition, the presence of (-)-epicatechin (1), (+)-catechin (2), (-)-epigallocatechin (3), (+)-gallocatechin (4), procyanidins B-1 (5), B-3 (6), A-1 (8) and A-2 (9), and cinnamtannins B1 (10), D1 (11), B2 (12) and D2 (13) in this plant was demonstrared.Keywords - Vaccinium vitis-idaea; Ericaceae; doubly-bonded proanthocyanidin; procyanidin; condensed tannin; flavan-3-ol; thiolytic degradation