title: Cytotoxicity and effect on protease activity of copolymer extracts containing catechin.
abstract: OBJECTIVE
  To evaluate cytotoxicity and effect on protease activity of epigallocatechin-gallate extracted from experimental restorative dental copolymers in comparison to the control compound chlorhexidine.
  
  
  METHODS
  Copolymer disks were prepared from bis-GMA/TEGDMA (70/30 mol%) containing no compound (control) or 1% w/w of either epigallocatechin-gallate or chlorhexidine. MDPC-23 odontoblast-like cells were seeded with the copolymer extracts leached out into deionized water. Cell metabolic activity was quantified by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at 24, 48, 72 h. Inhibition of protease activity by resin extracts was measured by a collagenolytic/genatinolytic enzyme activity assay and gelatin zymography. Data for MTT and protease inhibition were analyzed using two-way ANOVA followed by Tukey or Bonferroni post hoc tests (α=0.05).
  
  
  RESULTS
  The MTT revealed that at 72 h, extracts from control (16.7%) and chlorhexidine (22.3%) copolymers induced significant reduction in cell metabolism (p<0.05). All copolymer extracts caused enzymatic inhibition in a dose dependent manner (p<0.01). Even when highly diluted, epigallocatechin-gallate extract had a significant antiproteolytic activity (p<0.05). Zymograms showed that all extracts reduced activity of MMP-2 and MMP-9 (pro- and active forms), with MMP-9 exhibiting the highest percentage inhibition revealed by densitometry.
  
  
  CONCLUSIONS
  Epigallocatechin-gallate and chlorhexidine extracts did not exert cytotoxicity on evaluated cells when compared to control extracts. Both compounds retained antiproteolytic activity after extraction from a dental copolymer.
  
  
  CONCLUSIONS
  Once extracted from a dental copolymer, epigallocatechin-gallate is not cytotoxic and retains antiproteolytic activity. These results may allow incorporation of epigallocatechin-gallate as a natural-safe alternative to chlorhexidine in functionalized restorative materials.
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil. Electronic address: brunolzarella@usp.br.
authors: Bruno Lara
authors: BL
authors: Zarella
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil. Electronic address: mbuzalaf@fob.usp.br.
authors: Marília Afonso Rabelo
authors: MA
authors: Buzalaf
authors: Department of Dentistry, University of Sagrado Coração, Bauru, SP 17011-160, Brazil. Electronic address: thiemikato@gmail.com.
authors: Melissa Thiemi
authors: MT
authors: Kato
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil. Electronic address: angelhannas@hotmail.com.
authors: Angelica Reis
authors: AR
authors: Hannas
authors: Institute of Dentistry, University of Oulu, and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu FI-90014, Finland; Department of Oral and Maxillofacial Diseases, University of Helsinki, and Helsinki University Hospital, Helsinki FI-00014, Finland. Electronic address: tuula.salo@oulu.fi.
authors: Tuula
authors: T
authors: Salo
authors: Institute of Dentistry, University of Oulu, and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu FI-90014, Finland; Department of Oral and Maxillofacial Diseases, University of Helsinki, and Helsinki University Hospital, Helsinki FI-00014, Finland. Electronic address: leo.tjaderhane@oulu.fi.
authors: Leo
authors: L
authors: Tjäderhane
authors: Department of Clinical Sciences-Restorative, Faculty of Dentistry, University of Toronto, Toronto, ON M5G1G6, Canada. Electronic address: anuradha.prakki@dentistry.utoronto.ca.
authors: Anuradha
authors: A
authors: Prakki
mesh_terms: D000818:Animals; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D002710:Chlorhexidine / Q000737:chemistry / Q000494:pharmacology; D003188:Composite Resins / Q000008:administration & dosage* / Q000737:chemistry; D003731:Dental Caries; D003764:Dental Materials / Q000494:pharmacology; D003804:Dentin / Q000187:drug effects; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000187:drug effects; D051379:Mice; D009804:Odontoblasts / Q000187:drug effects; D010447:Peptide Hydrolases / Q000378:metabolism*; D011108:Polymers / Q000008:administration & dosage* / Q000737:chemistry; D011480:Protease Inhibitors / Q000008:administration & dosage* / Q000737:chemistry; D012117:Resins, Synthetic / Q000494:pharmacology
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D011108:Polymers; D011480:Protease Inhibitors; D012117:Resins, Synthetic; D002392:Catechin; C045651:epigallocatechin gallate; D010447:Peptide Hydrolases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D002710:Chlorhexidine
keywords: Caries; Dentin; Matrix-metalloproteinases; Odontoblasts; Resins; Zymography