Oligomeric proanthocyanidins inhibit endogenous enzymatic activity of deciduous carious dentin

Abstract

Dentin endogenous proteases are involved in the progression of dental caries. This study investigated the proteolytic activity of endogenous enzymes of carious and sound dentin of primary teeth and the potential selective inhibitory effect of plant-derived proanthocyanidins (PACs). Carious and sound dentin from forty extracted primary teeth were collected and cryo-pulverized into a fine powder. Two PAC mixtures were prepared from grape seeds ( Vitis vinifera , Vv ), an oligomer enriched and polymer depleted extract ( Vv e ) as well as a further refined mixture containing primarily trimeric and tetrameric PACs ( Vv 3+4 ). Fluorescein conjugate-gelatin was used as cleavage substrate. The inhibition of endogenous protease activity was determined by the fluorescence emission intensity of cleaved gelatin at 535 nm over a 24-hour period. Deciduous carious dentin exhibited higher gelatinolytic activity (~7 fold higher) than sound dentin (p < 0.001). Treatment with 0.65% Vv e or Vv 3+4 inhibited proteolytic activity of the primary teeth effectively (p < 0.001). Endogenous enzymes are highly active in carious dentin, contributing for host-driven degradation along with the breakdown by cariogenic bacteria. The protease inhibitory effect of both the refined Vv 3+4 preparation and its Vv e precursor appears to be promising as an effective strategy to impair caries progression in primary teeth.