title: Scavenging property of three cresol isomers against H2O2, hypochlorite, superoxide and hydroxyl radicals.
abstract: Formocresol has long been used for pulpotomy of primary teeth and as an intracanal medicament. Little is known, however, about the pharmacological effect of tricresols. This study showed that three cresol isomers, o-cresol, m-cresol and p-cresol, are H2O2 scavengers with a 50% inhibitory concentration (IC50) of 502, 6.7 and 10.16 microM, respectively. o-, m- and p-cresol were also shown to be effective scavengers of superoxide radicals generated by xanthine/xanthine oxidase with an IC50 of 282, 153 and > 4000 microM, respectively, as analyzed by luminometer. o-, m- and p-cresol showed protective effects on the DNA breaks generated by H2O2/FeCl2 and FeCl3/ascorbate/H2O2 systems at concentrations ranging from 70 microM to 1.43 mM, o-, m- and p-cresol also showed differential protective effects against DNA breaks induced by 0.17% NaOCl with 100% inhibitory concentration (IC100) of about 10, 1 and 10 mM, respectively. In addition, reaction with 3% H2O2 and 0.17% NaOCl completely prevented NaOCl-induced DNA breaks. The results indicate that the three cresol isomers are effective ROS scavengers and may prevent ROS induced damage when used as pulpotomy agents or as intracanal medicaments. Owing to the difference in the position of the functional hydroxyl group in the three cresol isomers, m-cresol is the most effective ROS scavenger. Concomitant use of H2O2 for root canal irrigation may diminish both the tissue dissolving capacity of NaOCl and NaOCl-induced DNA damage.
authors.affiliation: Department of Dentistry, Chang-Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: S Y
authors.initials: SY
authors.lastname: Yeung
authors.forename: W H
authors.initials: WH
authors.lastname: Lan
authors.forename: C S
authors.initials: CS
authors.lastname: Huang
authors.forename: C P
authors.initials: CP
authors.lastname: Lin
authors.forename: C P
authors.initials: CP
authors.lastname: Chan
authors.forename: M C
authors.initials: MC
authors.lastname: Chang
authors.forename: J H
authors.initials: JH
authors.lastname: Jeng
mesh_terms: D000166:Acridines / Q000737:chemistry; D003408:Cresols / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects; D004347:Drug Interactions; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D006997:Hypochlorous Acid / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D007536:Isomerism; D008163:Luminescent Measurements; D013481:Superoxides / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000166:Acridines; D003408:Cresols; D016166:Free Radical Scavengers; D013481:Superoxides; D019820:Xanthine; C033472:10,10'-dimethyl-9,9'-biacridinium; D017665:Hydroxyl Radical; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase