title: Superoxide formation and DNA damage induced by a fragrant furanone in the presence of copper(II).
abstract: 2,5-Dimethyl-4-hydroxy-3(2H)-furanone (2,5-DMHF), a caramel-like fragrant compound found in may processed foodstuff, has been reported to be mutagenic. 4,5-Dimethyl-3-hydroxy-2(5H)-furanone (4,5-DMHF), which is a similar characteristic fragrant compound, has no report concerning its mutagenicity. DNA damage by 2,5-DMHF and 4,5-DMHF was investigated by using DNA fragments obtained from the p53 tumor suppressor gene. 2,5-DMHF induced DNA damage extensively in the presence of Cu(II), but only slightly in the presence of Fe(III). 4,5-DMHF did not cause metal-dependent DNA damage. Bathocuproine, a Cu(I)-specific chelator, and catalase inhibited DNA damage induced by 2,5-DMHF plus Cu(II), whereas free hydroxyl radical scavengers did not. The order of DNA cleavage sites was thymine, cytosine > guanine residues. The site-specific DNA damage and effects of scavengers show that DNA-copper-oxygen complex rather than free .OH are involved in the DNA damage. Formation of 8-oxodeoxyguanosine (8-oxodG) by 2,5-DMHF increased with its concentration in the presence of Cu(II), whereas 8-oxodG formation increased only slightly in the presence of Fe(III). Degradation of 2,5-DMHF was efficiently accelerated by Cu(II), but only slightly accelerated by Fe(III). The degradation of 4,5-DMHF was little even in the presence of metal ions. Examination using cytochrome c suggest that superoxide was generated from 2,5-DMHF. Stoichiometric study of Cu(II) reduction revealed that autoxidation of 2,5-DMHF could offer 4-electron reduction. These results suggest that, at least in vitro and in an acellular system, 2,5-DMHF generates superoxide and subsequently hydrogen peroxide to induce metal-dependent DNA damage.
authors.affiliation: Department of Hygiene, Mie University School of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamashita
authors.forename: M
authors.initials: M
authors.lastname: Murata
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Hiraku
authors.forename: T
authors.initials: T
authors.lastname: Yoshinaga
authors.forename: S
authors.initials: S
authors.lastname: Kawanishi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D002417:Cattle; D003300:Copper / Q000737:chemistry / Q000633:toxicity*; D004249:DNA Damage; D053938:DNA Fragmentation; D003849:Deoxyguanosine / Q000031:analogs & derivatives; D016166:Free Radical Scavengers; D005663:Furans / Q000737:chemistry / Q000633:toxicity*; D005960:Glucosides / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D009153:Mutagens / Q000737:chemistry / Q000633:toxicity*; D010084:Oxidation-Reduction; D010761:Phosphorus Radioisotopes; D013056:Spectrophotometry, Ultraviolet; D013481:Superoxides / Q000378:metabolism*
chemical_list: C103577:2,5-dimethyl-4-hydroxy-3(2H)-furanone 6'-O-malonyl-glucopyranoside; D016166:Free Radical Scavengers; D005663:Furans; D005960:Glucosides; D009153:Mutagens; D010761:Phosphorus Radioisotopes; D013481:Superoxides; D003300:Copper; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine