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

Abstract

Objective To investigate the relationship between the structures of polyphenolic compounds found in grape seed extract (GSE) and their activity in cross-linking dentin collagen in clinically relevant settings. Methods Representative monomeric and dimeric GSE constituents including (+)-catechin (pCT), (−)-catechin (CT), (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin gallate (EGCG), procyanidin B2 and a pCT-pCT dimer were purchased or synthesized. GSE was separated into low (PALM) and high molecular weight (PAHM) fractions. Human molars were processed into dentin films and beams. After demineralization, 11 groups of films (n=5) were treated for 1 min with the aforementioned reagents (1 wt% in 50/50 ethanol/water) and 1 group remained untreated. The films were studied by Fourier transform infrared spectroscopy (FTIR) followed by a quantitative mass spectroscopy-based digestion assay. Tensile properties of demineralized dentin beams were evaluated (n=7) after treatments (2h and 24h) with selective GSE species that were found to protect dentin collagen from collagenase. Results Efficacy of GSE constituents in cross-linking dentin collagen was dependent on molecular size and galloylation. Non-galloylated species with degree of polymerization up to two, including pCT, CT, EC, EGC, procyanidin B2 and pCT-pCT dimer were not active. Galloylated species were active starting from monomeric form, including ECG, EGCG, PALM, GSE and PAHM. PALM induced the best overall improvement in tensile properties of dentin collagen. Significance Identification under clinically relevant settings of structural features that contribute to GSE constituents’ efficacy in stabilizing demineralized dentin matrix has immediate impact on optimizing GSE’s use in dentin bonding.

Effects of epicatechin, a crosslinking agent, on human dental pulp cells cultured in collagen scaffolds

“…Epicatechin and its derivatives are known to have great potential for anti-inflammatory 7 and anti-cancer effects 4 , 8 . Furthermore, they are also used as crosslinking agents 3 , 15 . However, there have been no studies regarding the effect of ECN on human dental pulp cells (hDPCs) or on the cells cultured in a collagen hydrogel scaffold.…”

Effect of tea root-derived proanthocyanidin fractions on protection of dentin collagen

“…Previous studies have shown that PAs from different sources exerted distinct protective effects on dentin. [28][29][30] The proportion of PA oligomers is often regarded as a key indicator of their effects, based on their abilities to scavenge radicals and resist oxidation. However, oligomers with a low degree of polymerization exhibit insufficient convergence capacity and weak binding to dentin collagen.…”

Effect of Grape Seed Extract Solution on the Microhardness of the Root Canal Dentin: An in Vitro Study

“…Therefore, the role of proanthocyanidin molecules in GSE solution with glycerin could not be optimum to increase the microhardness of dentin in the root canal. In a previous study by Liu et al (2015), the small molecular size of proanthocyanidin reported providing the best results in triggering an increase in dentin collagen's mechanical properties [30].…”