Galloyl moieties enhance the dentin biomodification potential of plant-derived catechins

Abstract

Proanthocyanidin (PAC) rich plant-derived agents have been shown to enhance dentin biomechanical properties and resistance to collagenase degradation. This study systematically investigated the interaction of chemically well-defined monomeric catechins with dentin extracellular matrix components by evaluating dentin mechanical properties as well as activities of matrix metalloproteinases (MMPs) and cysteine-cathepsins (CTs). Demineralized dentin beams (n = 15) were incubated for 1 hr with 0.65% (+)-catechin (C), (−)-catechin gallate (CG), (−)-gallocatechin gallate (GCG), (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC), and (−)-epigallocatechin-3-gallate (EGCG). Modulus of elasticity (E) and E fold increase were determined, comparing specimens at baseline and after treatment. Biodegradation rates were assessed by differences in percentage of dry mass before and after incubation with bacterial collagenase. The inhibition of MMP-9 and CT-B by 0.65%, 0.065% and 0.0065% of each catechin was determined using fluorimetric proteolytic assay kits. All monomeric catechins led to a significant increase in E. EGCG showed the highest E fold increase, followed by ECG, CG and GCG. EGCG, ECG, GCG and CG significantly lowered biodegradation rates and inhibited both MMP-9 and CT-B at a concentration of 0.65%. Overall, the 3-O-galloylated monomeric catechins are clearly more potent than their non-galloylated analogues in improving dentin mechanical properties, stabilizing collagen against proteolytic degradation, and inhibiting the activity of MMPs and CTs. The results indicate that galloylation is a key pharmacophore in the monomeric and likely also in the oligomeric PACs that exhibit high cross-linking potential for dentin extracellular matrix.

Bond Strength between Fiber Posts and Root Dentin Treated with Natural Cross-linkers

“…This is the first study to show the long-term effects of GSE in biostability of the adhesion of fiber posts to root dentin. The maintenance of bond strength in GSE-treated dentin after 12 months of storage is related to its ability to mediate cross-links in collagen-based tissues like dentin (13)(14)(15)(16). The interaction of PACs and collagen results in the formation of complexes that are believed to be stabilized primarily by hydrogen bonding between the protein amide carbonyl and the phenolic hydroxyl group of polyphenols (21) in addition to covalent and hydrophobic bonds.…”

“…Another option for improving the stability of dentin collagen is the use of natural cross-linking agents. Some proanthocyanidin (PAC)-rich plant extracts have been shown to stimulate interfibrillar, intrafibrillar, and intermicrofibrillar cross-links in the collagen matrix (13)(14)(15)(16)(17). PAC-rich extract (grape seed extract [GSE]) increases the biomechanical properties and biostability of demineralized dentin matrix (14,15) and the immediate resin-dentin bond strength (13).…”

Remineralization Potential of Mints Containing Bioactive Agents in Artificially Induced Root Caries

“…Although all mints studied contained the same concentration of GT extract (2%), mint C contained the highest concentration of EGCg. Among commonly found monomeric catechins, EGCg is the most potent monomeric PAC in dentin, being attributed to the 3-0-galloylation moiety [Vidal et al, 2014a]. Therefore, it is plausible to state that higher concentration of EGCg will increase the bioactivity of an extract [Aguiar et al, 2014].…”

“…GT is largely composed of monomeric epigallocatechin gallate (EGCg) that enhances the biomechanical properties of the dentin organic matrix [Vidal et al, 2014a] and suppresses specific virulence factors associated with Streptococcus mutans cariogenicity, ultimately exerting anticaries [Xu et al, 2011a] and antierosive [Kato et al, 2012] properties. Another bioactive agent that is studied under different strategies as a source of calcium and phosphate ions is amorphous calcium phosphate (ACP).…”

Molecular weight and galloylation affect grape seed extract constituents’ ability to cross-link dentin collagen in clinically relevant time

“…An endeavor to address these problems while preserving GSE’s clinical efficacy would require a precise knowledge of the relationship between GSE components’ structure and their collagen-stabilizing activity. A few recent investigations [19, 20] attempted to probe the biomodification potential of various monomeric and oligomeric species that constitute GSE, but clinical relevance was not of priority in the experimental design.…”