Enhancement of Dentin Strength and Inhibition of Collagenase Induced Biodegradation by Plant Proanthocyanidins

Proanthocyanidins are oligomers composed of flavan-3-ol units, primarily known for their antioxidant potential. The present study involves chemical and biological characterization of the PAC rich grape seed and cocoa fruit extracts with dentin enhancing properties so as to map their bioactivity on the dentin-collagen matrix of the tooth. The dentin matrix is an important component of tooth structure and, thus, a stronger and stable dentin (type-I collagen) is required for restorative procedures. We have recently shown that the PACs can improve the mechanical properties of dentin. Thus, one important aspect of their mechanistic characterization is to separate the PACs according to their degree of oligomerization (DO) followed by IT-TOF MS analysis. Active fractions from grape seed and cocoa extracts have shown 5 to 7 fold increased bioactivity. A method was developed to separate cocoa extract based on its DO using NP-HPLC. Dentin stiffness assays have also been performed on the commercially available procyanidins A1, A2, B1, B2 and C1 as well as the galloylated and non-galloylated catechin and epicatechin monomers to establish structure activity relationships. Altogether, the observed potency and phytochemical results obtained bode well on the potential clinical application of the phytopreparations under development in this project.