Abstract
Six triflavanoid procyanidins have been isolated from medicinal birch bark and their structures unequivocally established as epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin (C 1), catechin-(4α→8)-catechin- (4α→8)-catechin (C 2), catechin-(4α→8)-epicatechin-(4β→8)-epicatechin, epicatechin-(4β→8)-epicatechin-(4β→8)-catechin, epicatechin-(4β→8)-epicatechin-(4β→6)-catechin and epicatechin-(4β→6)-epicatechin-(4β→8)-catechin. The bonding patterns in the last three regioisomers, and also the sequence of units in these representatives of mixed stereochemistry, were resolved by 1H NMR spectroscopy through application of diagnostic chernical-shift data obtained from high-temperature spectra of their methyl ether acetate derivatives. Additionally, the occurrence of(+)- catechin and its 7- O-β- d-xylopyranoside, (-)-epicatechin and procyanidins B 1-B 3, B 5-B 7 was demonstrated.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
