Open AccessTargeting Trimeric and Tetrameric Proanthocyanidins of Cinnamomum verum Bark as Bioactives for Dental Therapies
Author(s) -
JooWon Nam,
Rasika S. Phansalkar,
David C. Lankin,
James B. McAlpine,
Ariene A. Leme-Kraus,
Ana K. Bedran-Russo,
Shao-g Chen,
Guido F. Pauli
Publication year - 2020
Publication title -
journal of natural products
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.976
H-Index - 139
eISSN - 1520-6025
pISSN - 0163-3864
DOI - 10.1021/acs.jnatprod.0c00570
Subject(s) - proanthocyanidin , trimer , chemistry , catechin , stereochemistry , bark (sound) , phytochemical , two dimensional nuclear magnetic resonance spectroscopy , polyphenol , biochemistry , organic chemistry , dimer , biology , ecology , antioxidant
The present study elucidated the structures of three A-type tri- and tetrameric proanthocyanidins (PACs) isolated from Cinnamomum verum bark to the level of absolute configuration and determined their dental bioactivity using two therapeutically relevant bioassays. After selecting a PAC oligomer fraction via a biologically diverse bioassay-guided process, in tandem with centrifugal partition chromatography, phytochemical studies led to the isolation of PAC oligomers that represent the main bioactive principles of C. verum : two A-type tetrameric PACs, epicatechin-(2β→ O →7,4β→8)-epicatechin-(4β→6)-epicatechin-(2β→ O →7,4β→8)-catechin ( 1 ) and parameritannin A1 ( 2 ), together with a trimer, cinnamtannin B1 ( 3 ). Structure determination of the underivatized proanthocyanidins utilized a combination of HRESIMS, ECD, 1D/2D NMR, and 1 H iterative full spin analysis data and led to NMR-based evidence for the deduction of absolute configuration in constituent catechin and epicatechin monomeric units.