title: Photochemical properties of ofloxacin involved in oxidative DNA damage: a comparison with rufloxacin.
abstract: Photodegradation of ofloxacin (OFX) under aerobic conditions gives rise to N-demethylation, mainly involving coupling of radical cation OFX(*)(+ )()with superoxide radical anion. Although H(2)O(2) is produced as a byproduct, oxidative damage to DNA to give 8-OH-dGuo is associated with a type II mechanism. When the photosensitizing potentials of OFX and rufloxacin (RFX) are compared under the same conditions, the latter is shown to produce a much higher degree of DNA oxidation despite the close structural similarity. This is explained by a decrease of the triplet energy when sulfur instead of oxygen is attached to position 8 of the fluoroquinolone ring system. As a consequence, phosphate anions are able to quench OFX triplet but not RFX triplet; this reveals that the reaction medium has a strong influence on the photochemistry of OFX and hence on its photobiological properties.
authors.affiliation: Departamento de Química/Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Valencia, Spain.
authors.forename: M Consuelo
authors.initials: MC
authors.lastname: Cuquerella
authors.forename: Francisco
authors.initials: F
authors.lastname: Boscá
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
authors.forename: Alessandra
authors.initials: A
authors.lastname: Belvedere
authors.forename: Alfio
authors.initials: A
authors.lastname: Catalfo
authors.forename: Guido
authors.initials: G
authors.lastname: De Guidi
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000528:radiation effects*; D004249:DNA Damage; D005453:Fluorescence; D024841:Fluoroquinolones / Q000737:chemistry / Q000528:radiation effects*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007834:Lasers; D015242:Ofloxacin / Q000737:chemistry / Q000528:radiation effects*; D010084:Oxidation-Reduction; D010777:Photochemistry; D015363:Quinolones / Q000737:chemistry / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D015363:Quinolones; D015242:Ofloxacin; D006861:Hydrogen Peroxide; C060328:rufloxacin