Planta Med 2016; 82 - OA50
DOI: 10.1055/s-0036-1578686

Grape Seed Proanthocyanidins: A Novel Source Of Dental Biomaterials And Unique Phytochemistry

RS Phansalkar 1, JW Nam 1, SN Chen 1, J Bisson 1, D Kulakowski 1, 2, JB McAlpine 1, AA Leme 2, CMP Vidal 2, T Aguiar 2, A Bedran-Russo 2, GF Pauli 1
  • 1Department of Medicinal Chemistry & Pharmacognosy, College of Pharmacy
  • 2Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 833 S Wood Street, Chicago IL 60607, USA

Composite-based, tooth colored dental restorations, in spite of their aesthetic appeal, are limited by a short life span. Every subsequent restoration results in the loss of healthy dental tissue. Thus, a bio-mimetic approach has been developed to enhance the mechanical strength of dentin using plant-derived proanthocyanidins (PACs). From a panel of eight active plants, grape seed extract showed the highest dentin biomodification potential, a 15-fold enhancement of dentin stiffness measured in MPa. Fractions with varying degrees of polymerization (DP) were obtained using solvent partitioning and centrifugal partition chromatography (CPC). Oligomeric PACs (OPACs, DP 2 – 7) surfaced as the most promising dentin biomodifiers compared to the constituent monomers and polymers (Dp ≥8). OPACs with DP 3 to 4 showed the most efficacious dentin-PAC interaction as evaluated by bio-mechanical tests. While one arm of the separation focused on the development of a highly active custom-made tri- and tetra-meric OPAC enriched mixture (GSE3+4), OPACs were also purified as single chemical entities. OPACs with predominantly 4β→8/6 B-type interflavan linkages (IFLs) along with one having a unique 2→8 IFL were isolated. Structural characterization employed 1D and 2D NMR at low temperature (255K) to overcome line-broadening due to atropisomerism. The presence of gallate ester moieties is a characteristic feature of grape seed PACs and the biological evaluation also highlighted the enhanced effect of galloylated OPACs on dentin biomodification. Grape seeds are thus, a viable source of novel restorative dental biomaterials and highlight a novel application of plant-based natural products in the biomedical field.

Fig. 1