title: Degradation of the drug sodium diclofenac by Trametes versicolor pellets and identification of some intermediates by NMR.
abstract: Degradation of diclofenac sodium, a nonsteroidal anti-inflammatory drug widely found in the aquatic environment, was assessed using the white-rot fungus Trametes versicolor. Almost complete diclofenac removal (> or = 94%) occurred the first hour with T. versicolor pellets when the drug was added at relatively high (10 mg L(-1)) and environmentally relevant low (45 microg L(-1)) concentrations in a defined liquid medium. In vivo and in vitro experiments using the cytochrome P450 inhibitor 1-aminobenzotriazole and purified laccase, respectively, suggested at least two different mechanisms employed by T. versicolor to initiate diclofenac degradation. Two hydroxylated metabolites, 4'-hydroxydiclofenac and 5-hydroxydiclofenac, were structurally elucidated by nuclear magnetic resonance as degradation intermediates in fungal cultures spiked with diclofenac. Both parent compound and intermediates disappeared after 24 h leading to a decrease in ecotoxicity calculated by the Microtox test. Laccase-catalyzed transformation of diclofenac led to the formation of 4-(2,6-dichlorophenylamino)-1,3-benzenedimethanol, which was not detected in in vivo experiments probably due to the low laccase activity levels observed through the first hours of incubation.
authors.affiliation: Departament d'Enginyeria Química and Institut de Ciència i Tecnologia Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Ernest
authors.initials: E
authors.lastname: Marco-Urrea
authors.forename: Miriam
authors.initials: M
authors.lastname: Pérez-Trujillo
authors.forename: Carles
authors.initials: C
authors.lastname: Cruz-Morató
authors.forename: Gloria
authors.initials: G
authors.lastname: Caminal
authors.forename: Teresa
authors.initials: T
authors.lastname: Vicent
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism; D001673:Biodegradation, Environmental; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004008:Diclofenac / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D006900:Hydroxylation; D042845:Laccase / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D055454:Trametes / Q000378:metabolism*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac; D003577:Cytochrome P-450 Enzyme System; D042845:Laccase; C117715:5-hydroxydiclofenac; C108036:4'-hydroxydiclofenac