title: Quenching of superoxide ions by curcumin. A mechanistic study in acetonitrile.
abstract: The quenching of superoxide ions, O2.-, by curcumin has been studied by electrogenerating this anion radical from oxygen dissolved in acetonitrile solvent (that is, at best, a mimic of the lipofilic layer of biological membranes), containing known amounts of curcumin. Voltammetric tests, combined with coulometric and spectrophotometric measurements, pointed out that each mol of curcumin is able to react with six mols of such anion radical, through a process initiated by an acid-base step, which provides the perhydroxyl radical, HO2.; that disproportionates rapidly to the anionic form of hydrogen peroxide, HO2-, and oxygen, which is thus partially regenerated. At the same time, curcumin is converted to the corresponding three-charged anion. The strict resemblance existing between the mechanism of the rapid superoxide radical decay caused by curcumin and that involved in the presence of the superoxodismutase enzyme (SOD) is also underlined.
authors.affiliation: Department of Chemical Sciences and Technology, University of Udine, via Cotonificio 108, 33100 Udine, Italy.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Toniolo
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Narda
authors.forename: Sabina
authors.initials: S
authors.lastname: Susmel
authors.forename: Mario
authors.initials: M
authors.lastname: Martelli
authors.forename: Laura
authors.initials: L
authors.lastname: Martelli
authors.forename: Gino
authors.initials: G
authors.lastname: Bontempelli
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000970:Antineoplastic Agents / Q000737:chemistry*; D003474:Curcumin / Q000737:chemistry*; D004563:Electrochemistry; D013056:Spectrophotometry, Ultraviolet; D013482:Superoxide Dismutase / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry*
chemical_list: D000097:Acetonitriles; D000970:Antineoplastic Agents; D013481:Superoxides; D013482:Superoxide Dismutase; D003474:Curcumin; C032159:acetonitrile