Tri- and Tetrameric Proanthocyanidins with Dentin Bioactivities from Pinus massoniana

Abstract

Guided by dentin biomechanical bioactivity, this phytochemical study led to the elucidation of an extended set of structurally demanding proanthocyanidins (PACs). Unambiguous structure determination involved detailed spectroscopic and chemical characterization of four A-type dimers (2, 4–6), seven trimers (10–16), and six tetramers (17–22). New outcomes confirm the feasibility of determining the absolute configuration of the catechol monomers in oligomeric PACs by 1D and 2D NMR. Electronic circular dichroism (ECD) as well as phloroglucinolysis followed by MS and chiral phase HPLC analysis generated the necessary chiral reference data.

Proanthocyanidin Tetramers and Pentamers from Cinnamomum verum Bark and Their Dentin Biomodification Bioactivities

“…Guided by dentin bioactivity assessment, our group has identified a series of A-type oligomeric PACs from pine bark, 10,12,13,17,18 as well as B-type PACs from grape seeds, 19 all with potent dentin biomodification activity. To enhance the communication across disciplines, particularly at the chemistrybiology interface, better reveal the complexity of PACs structure, and foster the establishment of dentin activitystructure relationships (SARs), we recently proposed the PAC Block ARray (PACBAR) system as more precise and better readable structural descriptors of PACs.…”

Tri- and Tetrameric Proanthocyanidins with Dentin Bioactivities from Pinus massoniana

“…The original NMR data (FIDs) are made available at DOI: . The preprint of this article is available at DOI: .…”

Rare A-Type, New Spiro-Type, and Highly Oligomeric Proanthocyanidins from Pinus massoniana

“…This unprecedented linkage combination is the plausible reason for the observed atropisomeric line-broadening in its NMR spectra, which otherwise is atypical of A-type PACs. Pinuspirotetrin (2) represents the first PAC with a heterodimeric framework consisting of a spiro-type dimer connected with an A-type dimer. Also characterized in underivatized form, and exhibiting dentin bioactivity, pinumassohexin (3) was elucidated as a hexameric PAC with mixed A+B-type interflavanyl linkages (IFLs), assembled from the known tetramer, peanut procyanidin E, 8 and the dimer, epicatechin-(2O7,48)-ent-catechin (5), 8,9 via a 46 bond.…”

“…Representing a group of vast structural diversity, PACs exhibit a broad spectrum of bioactivities. [1][2][3][4][5][6][7] Specific to pine bark, a series of tri-and tetrameric PACs has the demonstrated capability of enhancing the biomechanical properties of dentin and…”