title: The anti-oxidant effects of melatonin derivatives on human gingival fibroblasts.
abstract: OBJECTIVE
  Aim of this in vitro study was to evaluate the anti-oxidant activity of indole ring modified melatonin derivatives as compared with melatonin in primary human gingival fibroblast (HGF) cells.
  
  
  METHODS
  Anti-oxidant activity of melatonin (MLT), acetyl-melatonin (AMLT) and benzoyl-melatonin (BMLT) was evaluated by5 standard methods as follows: 2, 2-diphenyl-1-picrylhydrazyl (DPPH); ferric ion reducing antioxidant power (FRAP); superoxide anion scavenging; nitric oxide (NO) scavenging; and thiobarbituric acid reactive substances (TBARs).Evaluation of cellular antioxidant activity (CAA) and protectivity against H2O2induced cellular damage was performed via MTT assay in HGF cells.
  
  
  RESULTS
  According to the standard anti-oxidant assays, the antioxidant power of AMLT and BMLT were slightly less than MLT in FRAP and superoxide scavenging assays. In the NO scavenging and TBARs assays, BMLT and AMLT were more potent than MLT, whereas DPPH assays demonstrated that MLT was more potent than others. BMLT and AMLT had more potent anti-oxidant and protective activities against H2O2in HGF cells as compared with MLT.
  
  
  CONCLUSIONS
  MLT derivatives demonstrated different anti-oxidant activities as compared with MLT, depending upon assays. These findings imply that N-indole substitution of MLT may help to improve hydrogen atom transfer to free radicals but electron transfer property is slightly decreased. Anti-oxidant and protective effects of melatonin derivatives (AMLT and BMLT) on human gingival fibroblasts imply the potential use of these molecules as alternative therapeutics for chronic inflammatory oral diseases.
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand; Melatonin Research Group, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: pipat_cp@hotmail.com.
authors.forename: Chawapon
authors.initials: C
authors.lastname: Phiphatwatcharaded
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand; Melatonin Research Group, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: pploenthip@kku.ac.th.
authors.forename: Ploenthip
authors.initials: P
authors.lastname: Puthongking
authors.affiliation: Research Group of Chronic Inflammatory Oral Diseases and Systemic Diseases Associated with Oral Health, Khon Kaen University, Khon Kaen, 40002, Thailand; Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen, 40002, Thailand. Electronic address: cponla@kku.ac.th.
authors.forename: Ponlatham
authors.initials: P
authors.lastname: Chaiyarit
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand; Melatonin Research Group, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: pnutja@kku.ac.th.
authors.forename: Nutjaree Pratheepawanit
authors.initials: NP
authors.lastname: Johns
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand. Electronic address: sumon@kku.ac.th.
authors.forename: Sumon
authors.initials: S
authors.lastname: Sakolchai
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand; Melatonin Research Group, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: pramah@kku.ac.th.
authors.forename: Pramote
authors.initials: P
authors.lastname: Mahakunakorn
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D018929:Cell Culture Techniques; D004579:Electron Transport / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects*; D005609:Free Radicals / Q000378:metabolism; D005881:Gingiva / Q000187:drug effects*; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000378:metabolism; D007211:Indoles / Q000737:chemistry; D007501:Iron / Q000378:metabolism; D008550:Melatonin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D009059:Mouth Diseases / Q000188:drug therapy; D009569:Nitric Oxide; D013481:Superoxides; D017392:Thiobarbituric Acid Reactive Substances
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D007211:Indoles; C000595067:N-(2-(1-acetyl-5-methoxy-1H-indol-3-yl)ethyl)acetamide; C000595068:N-(2-(1-benzoyl-5-methoxy-1H-indol-3-yl)ethyl)acetamide; D017392:Thiobarbituric Acid Reactive Substances; D013481:Superoxides; D009569:Nitric Oxide; D006859:Hydrogen; C030374:indole; D006861:Hydrogen Peroxide; D007501:Iron; D008550:Melatonin
keywords: Anti-oxidant; Cellular antioxidant activity; Human gingival fibroblast cells; Hydrogen peroxide; Melatonin derivatives