title: Mechanism-based inactivation of CYP2C9 by linderane.
abstract: 1. Linderane (LDR), a furan-containing sesquiterpenoid, is found in Lindera aggregata (Sims) Kosterm, a common traditional Chinese herbal medicine. We thoroughly studied the irreversible inhibitory effect of LDR on cytochrome P450 2C9 (CYP2C9). 2. LDR caused a time- and concentration-dependent inactivation of CYP2C9. In addition, the inactivation of CYP2C9 by LDR was NADPH-dependent and irreversible. More than 50% of CYP2C9 activity was lost after its incubation with LDR at the concentration of 10 μM for 15 min at 30 °C. The maximal rate constant for inactivation (kinact) was found to be 0.0419 min(-1), and the concentration required for half-maximal inactivation (KI) was 1.26 μM, respectively. Glutathione (GSH), catalase, and superoxide dismutase (SOD) failed to protect CYP2C9 against inactivation by LDR. Diclofenac, a substrate of CYP2C9, prevented the enzyme from inactivation produced by LDR. The estimated partition ratio of the inactivation was approximately 227. 3. Two reactive intermediates, including furanoepoxide and γ-ketoenal, might be responsible for the observed enzyme inactivation. The formation of the intermediates was verified by chemical synthesis. Multiple P450 enzymes, including CYPs 1A2, 2B6, 2C9, 2C19, 2D6, 3A4, and 3A5, were found to be involved in the metabolic activation of LDR. In conclusion, LDR was characterized as a mechanism-based inactivator of CYP2C9.
authors.affiliation: a School of Pharmacy and.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: a School of Pharmacy and.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: a School of Pharmacy and.
authors.forename: Xu
authors.initials: X
authors.lastname: Mao
authors.affiliation: a School of Pharmacy and.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: a School of Pharmacy and.
authors.forename: Tong
authors.initials: T
authors.lastname: Yao
authors.affiliation: a School of Pharmacy and.
authors.forename: Ying
authors.initials: Y
authors.lastname: Peng
authors.affiliation: b Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang , Liaoning , China and.|c Division of Gastroenterology and Hepatology, Department of Pediatrics , Center for Developmental Therapeutics, Seattle Children's Research Institute, University of Washington School of Medicine , Seattle , WA , USA.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D065729:Cytochrome P-450 CYP2C9 / Q000378:metabolism*; D065607:Cytochrome P-450 Enzyme Inhibitors / Q000494:pharmacology*; D004008:Diclofenac / Q000494:pharmacology; D005663:Furans / Q000494:pharmacology*; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D009249:NADP / Q000378:metabolism; D012717:Sesquiterpenes / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000494:pharmacology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D065607:Cytochrome P-450 Enzyme Inhibitors; D005663:Furans; D012717:Sesquiterpenes; C000609537:linderane; D004008:Diclofenac; D009249:NADP; D002374:Catalase; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D013482:Superoxide Dismutase; D005978:Glutathione
keywords: CYP2C9; drug–drug interactions; linderane; mechanism-based inactivation; reactive metabolite