HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Identification of cytochrome P450 isoenzymes involved in metabolism of (+)-praeruptorin A, a calcium channel blocker, by human liver microsomes using ultra high-performance liquid chromatography coupled with tandem mass spectrometry.

Abstract
Angular-type pyranocoumarins (APs) show attractive prospects in anti-hypertension, chemotherapy and anti-HIV treatment. Previous studies revealed extensive hepatic metabolisms of several APs following similar pathways. This study investigated the enzyme kinetics and the main CYP450 isozyme(s) involved in metabolism of (+)-praeruptorin A (dPA), an AP with significant cardio-protective activities, in human liver microsomes (HLMs) using ultra high-performance liquid chromatography coupled with a hybrid quadrupole-linear ion trap mass spectrometry (UHPLC-QT-MS/MS). dPA produced 6 metabolites via hydrolysis (M1-M3), oxidation (M4-M6), and hydrolysis followed by acyl migration (M2 or M3). Oxidation at the C-3' side chain instead of the coumarin ring was consolidated with the aromatic proton signal in NMR spectra. The major metabolite (-)-cis-khellactone (M1) followed biphasic kinetics in HLMs with high affinity (Km1 0.02μM) and intrinsic clearance (CLint1, invitro1.29mL/min/mg protein), whereas other metabolites (M2-M6) fitted typical Michaelis-Menten kinetics with lower affinity (Km 3.85-39.13μM). Recombinant human CYP3A4 showed the highest activity toward M1 and M4 formation, while it was CYP2C19 for M2/M3 and M5 and CYP2B6 for M6. Principal component analysis of the metabolite formation profile of dPA also revealed the highest similarity between CYP3A4 and HLMs. Both quercetin (CYP2C8 inhibitor) and ketoconazole (CYP3A4 inhibitor) showed 60-100% inhibition of M1-M4 and M6 formations in HLMs, while M5 formation was mainly inhibited by α-naphthoflavone (CYP1A2 inhibitor, 70-80%) and quercetin (90%). Moreover, formations of all metabolites were predominantly inhibited by CYP3A4 antibody (37-68%). These findings shed a light on main involvement of CYP3A4 in human hepatic elimination of APs, indicating potential drug interactions.
AuthorsWang-Hui Jing, Yue-Lin Song, Ru Yan, Yi-Tao Wang
JournalJournal of pharmaceutical and biomedical analysis (J Pharm Biomed Anal) Vol. 77 Pg. 175-88 (Apr 15 2013) ISSN: 1873-264X [Electronic] England
PMID23434495 (Publication Type: Journal Article)
CopyrightCopyright © 2013 Elsevier B.V. All rights reserved.
Chemical References
  • Calcium Channel Blockers
  • Coumarins
  • cytochrome P-450 CYP2C subfamily
  • praeruptorin A
  • Cytochrome P-450 Enzyme System
  • khellactone
Topics
  • Calcium Channel Blockers (metabolism)
  • Chromatography, High Pressure Liquid (methods)
  • Coumarins (chemistry, metabolism)
  • Cytochrome P-450 Enzyme System (chemistry, metabolism)
  • Humans
  • Hydrolysis
  • Kinetics
  • Liver (chemistry, enzymology, metabolism)
  • Microsomes, Liver (chemistry, enzymology, metabolism)
  • Oxidation-Reduction
  • Tandem Mass Spectrometry (methods)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: