title: Synthesis, Characterization and Antioxidant Property of Quercetin-Tb(III) Complex.
abstract: OBJECTIVE
  Nearly all of flavonoids are good metal chelators and can chelate many metal ions to form different complexes. This article describes a synthesis of Quercetin-Tb(III) in methanol, characterized by using elemental analysis, UV-visible and evaluation of its antioxidant properties.
  
  
  METHODS
  The formation of complexes is realized from the UV-visible spectra which shows that the successive formation of Quercetin-Tb(III) occurs. To find out the antioxidant activity variation and the role of Tb(III) ion on the antioxidant activity of the complexes different radical scavenging methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) were used.
  
  
  RESULTS
  The results from DPPH, ABTS and FRAP methods showed that Quercetin and Quercetin-Tb(III) complex are capable of donating electron or hydrogen atom, and consequently could react with free radicals or terminate chain reactions in a time- and dose-dependent manner.
  
  
  CONCLUSIONS
  This study showed that the chelation of metal ions by Quercetin decrease the redox potential of Quercetin-metal complex.
authors: Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Jafar
authors: J
authors: Ezzati Nazhad Dolatabadi
authors: Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Ahad
authors: A
authors: Mokhtarzadeh
authors: Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Seyed Morteza
authors: SM
authors: Ghareghoran
authors: Department of Plant Biology, Faculty of Natural Science, University of Tabriz, Tabriz, Iran.
authors: Gholamreza
authors: G
authors: Dehghan
keywords: ABTS; Antioxidant; DPPH; FRAP; Flavonoid; Quercetin–Tb(III) complex