title: Synthesis, characterization and antioxidant activity copper-quercetin complex.
abstract: Quercetin (3,3',4',5,7-pentahydroxyflavone) one of the most abundant dietary flavonoids, has been investigated in the presence of Cu(II) in methanol. The spectroscopic studies (UV-vis, (1)H NMR and IR) were useful to assess the relevant interaction of Quercetin with Cu(II) ions, the chelation sites and dependence of the complex structure from the metal/ligand ratio. A 1:2 (L:M) complex was indicated by Job's method of continuous variation, which was applied to ascertain the stoichiometric composition of the complex. The antioxidant activities of the compounds were evaluated by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The complexed flavonoid was much more effective free radical scavengers than the free flavonoids.
authors.affiliation: Free Radical Research Laboratory, National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan. birjees_bukahri2k4@yahoo.com
authors.forename: S Birjees
authors.initials: SB
authors.lastname: Bukhari
authors.forename: Shahabuddin
authors.initials: S
authors.lastname: Memon
authors.forename: M
authors.initials: M
authors.lastname: Mahroof-Tahir
authors.forename: M I
authors.initials: MI
authors.lastname: Bhanger
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D015394:Molecular Structure; D011794:Quercetin / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013818:Thermogravimetry; D044366:Transition Temperature
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D046911:Macromolecular Substances; D003300:Copper; D011794:Quercetin