title: Experimental evidence that flavonoid metal complexes may act as mimics of superoxide dismutase.
abstract: Radical scavenging activities of flavonoids rutin, taxifolin, (-)-epicatechin, luteolin, and their complexes with transition metal (Fe2+, Fe3+, and Cu2+) towards superoxide were determined using illumination of riboflavin as source and NBT as detector of O*2-. The scavenger potencies of flavonoid metal complexes were significantly higher than those of the parent flavonoids. To elucidate the mechanism of this phenomenon, the rates of superoxide-dependent oxidation of flavonoids and their metal complexes in photochemical system with riboflavin were examined. It was found for the first time that flavonoids bound to metal ions were much less subjected to oxidation compared with those of free compounds. The findings directly demonstrate superoxide scavenging activity of metal ions in complexes with flavonoids and support earlier suggestions that flavonoid metal complexes may exhibit superoxide dismuting activity.
authors.affiliation: Byelorussian State University, Minsk, Belarus. kostyuk@bsu.by
authors.forename: V A
authors.initials: VA
authors.lastname: Kostyuk
authors.forename: A I
authors.initials: AI
authors.lastname: Potapovich
authors.forename: E N
authors.initials: EN
authors.lastname: Strigunova
authors.forename: T V
authors.initials: TV
authors.lastname: Kostyuk
authors.forename: I B
authors.initials: IB
authors.lastname: Afanas'ev
mesh_terms: D002392:Catechin / Q000737:chemistry; D003300:Copper / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000737:chemistry; D044948:Flavonols / Q000737:chemistry; D007501:Iron / Q000378:metabolism; D008024:Ligands; D008027:Light; D047311:Luteolin; D008956:Models, Chemical; D009580:Nitroblue Tetrazolium / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry; D017382:Reactive Oxygen Species; D012256:Riboflavin / Q000737:chemistry; D012431:Rutin / Q000737:chemistry; D013482:Superoxide Dismutase / Q000737:chemistry*; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D005419:Flavonoids; D044948:Flavonols; D008024:Ligands; D017382:Reactive Oxygen Species; D013481:Superoxides; D009580:Nitroblue Tetrazolium; D012431:Rutin; D003300:Copper; D002392:Catechin; D011794:Quercetin; C003377:taxifolin; D007501:Iron; D013482:Superoxide Dismutase; D047311:Luteolin; D010100:Oxygen; D012256:Riboflavin