posted on 2018-01-23, 00:00authored byR.S. Phansalkar, J.W. Nam, S.N. Chen, J.B. McAlpine, J.G. Napolitano, A. Leme, C.M. Vidal, T. Aguilar, A.K. Bedran-Russo, G.F. Pauli
Grape seeds are a rich source of polyphenols, especially proanthocyanidins (PACs), and are also known for the presence of galloylated oligomeric PACs (OPACs). The present study focuses on the phytochemical methodology for grape seed (O)PACs and their potential role as dentin biomodifiers to be used in restorative and reparative dentistry. A new method using centrifugal partition chromatography (CPC) was developed for the preparative separation of the grape seed (O)PACs. Orthogonal phytochemical profiling of the resulting CPC fractions was performed using C18 and diol HPLC, normal phase HPTLC, and IT-TOF MS analysis. A galloylated procyanidin dimer (1) was isolated from a CPC fraction in order to evaluate its potential to enhance dentin bio-mechanical properties. Moreover, it helped to evaluate the impact of the galloyl moiety on the observed bioactivity. Structure elucidation was performed using ESI-MS, 1D and 2D NMR analyses. For the first time, (1)H iterative full spin analysis (HiFSA) was performed on this type of molecule, enabling a detailed proton chemical shift and coupling constant assignment. The CPC fractions as well as 1 showed promising results in the dentin stiffness bioassay and indicate that they may be used as dental intervention biomaterial.
The authors are particularly grateful to Dr. Benjamin Ramirez from the Center for Structural
Biology at UIC for his general NMR support and his invaluable assistance in performing the low
temperature NMR experiments. We also thank an anonymous reviewer for helpful suggestions
regarding the nomenclature of oligomeric proanthocyanidins. This research was funded by grant
R01 DE021040 from NIDCR/NIH.
This is the author’s version of a work that was accepted for publication in Fitoterapia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fitoterapia. 2015 Mar;101:169-78. doi:10.1016/j.fitote.2014.12.006