title: Eugenol derivatives as potential anti-oxidants: is phenolic hydroxyl necessary to obtain an effect?
abstract: OBJECTIVE
  Eugenol, obtained from clove oil (Eugenia caryophyllata), possess several biological activities. It is anti-inflammatory, analgesic, anaesthesic, antipyretic, antiplatelet, anti-anaphylactic, anticonvulsant, anti-oxidant, antibacterial, antidepressant, antifungal and antiviral. The anti-oxidant activity of eugenol have already been proven. From this perspective testing, a series of planned structural derivatives of eugenol were screened to perform structural optimization and consequent increase of the potency of these biological activities.
  
  
  METHODS
  In an attempt to increase structural variability, 16 compounds were synthesized by acylation and alkylation of the phenolic hydroxyl group. Anti-oxidant activity capacity was based on the capture of DPPH radical (2,2-diphenyl-1-picryl-hydrazyl), ABTS radical 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), measure of TBARS (thiobarbituric acid-reactive species), total sulfhydryl and carbonyl content (eugenol derivatives final concentrations range from 50 to 200 μm).
  
  
  RESULTS
  Four derivatives presented an efficient concentration to decrease 50% of the DPPH radical (EC50 ) < 100 μm, which has a good potential as a free-radical scavenger. Three of these compounds also showed reduction of ABTS radical. Eugenol derivatives presenting alkyl or aryl (alkylic or arylic) groups substituting hydroxyl 1 of eugenol were effective in reducing lipid peroxidation, protein oxidative damage by carbonyl formation and increase total thiol content in cerebral cortex homogenates. In liver, the eugenol derivatives evaluated had no effect.
  
  
  CONCLUSIONS
  Our results suggest that these molecules are promising anti-oxidants agents.
authors.affiliation: Programa de Pós-Graduação em Bioquímica e Bioprospecção, UFPel, Campus Universitário s/n, Porto Alegre, RS, Brazil.
authors.forename: Marília
authors.initials: M
authors.lastname: d' Avila Farias
authors.forename: Pathise Souto
authors.initials: PS
authors.lastname: Oliveira
authors.forename: Filipe S Pereira
authors.initials: FS
authors.lastname: Dutra
authors.forename: Thiely Jacobsen
authors.initials: TJ
authors.lastname: Fernandes
authors.forename: Claudio M P
authors.initials: CM
authors.lastname: de Pereira
authors.forename: Simone Quintana
authors.initials: SQ
authors.lastname: de Oliveira
authors.forename: Francieli Moro
authors.initials: FM
authors.lastname: Stefanello
authors.forename: Claiton Leonetti
authors.initials: CL
authors.lastname: Lencina
authors.forename: Alethéa Gatto
authors.initials: AG
authors.lastname: Barschak
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D052160:Benzothiazoles / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D005054:Eugenol / Q000031:analogs & derivatives / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010851:Picrates / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D050050:Protein Carbonylation / Q000187:drug effects*; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013451:Sulfonic Acids / Q000378:metabolism; D027842:Syzygium / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D010851:Picrates; D010936:Plant Extracts; D013438:Sulfhydryl Compounds; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D005054:Eugenol; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: anti-oxidant activity; eugenol; eugenol derivatives; phenolic compounds