scholarly journals Development of a Novel Cytochrome P450 Bioaffinity Detection System Coupled Online to Gradient Reversed-Phase High-Performance Liquid Chromatography

2005 ◽  
Vol 10 (5) ◽  
pp. 427-436 ◽  
Author(s):  
Jeroen Kool ◽  
Sebastiaan M. van Liempd ◽  
Rawi Ramautar ◽  
Tim Schenk ◽  
John H. N. Meerman ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Detection System ◽  
Liver Microsomes ◽  
Detection Limits ◽  
Reversed Phase ◽  
Rat Liver Microsomes ◽  
The Individual ◽  
Gradient Hplc

A high-resolution screening platform, coupling online affinity detection for mammalian cytochrome P450s (Cyt P450s) to gradient reversed-phase high-performance liquid chromatography (HPLC), is described. To this end, the onlineCyt P450 enzyme affinity detection (EAD) system was optimized for enzyme (β-NF-induced rat liver microsomes), probe substrate (ethoxyresorufine), and organic modifier (methanol or acetonitrile). The optimized Cyt P450 EAD system has first been evaluated in a flow injection analysis (FIA) mode with 7 known ligands of Cyt P450 1A1/1A2 (β-naphthoflavone, ßnaphthoflavone, ellipticine, 9-hydroxy-ellipticine, fluvoxamine, caffein, and phenacetin). Subsequently, IC 50 valueswere online in FIA-mode determined and compared with those obtained with standardmicrosomal assay conditions. The IC 50 values obtained with the online Cyt P450 EAD system agreed well with the IC 50 values obtained in the standard assays. For highaffinity ligands ofCyt P450 1A1/1A2, detection limits of 1 to 3 pmol injected ( n= 3; signal to noise [S/N] = 3) were obtained. The individual inhibitory properties of ligands in mixtures of the ligands were subsequently investigated using an optimized Cyt P450 EAD system online coupled to gradient HPLC. Using the integrated online gradient HPLC Cyt P450 EAD platform, detection limits of 10 to 25 pmol injected ( n= 1; S/N= 3) were obtained for high-affinity ligands. It is concluded that this novel screening technology offers new perspectives for rapid and sensitive screening of individual compounds in mixtures exhibiting affinity for liver microsomal Cyt P450s.

scholarly journals Validation of an HPLC Method for the Simultaneous Quantification of Metabolic Reaction Products Catalysed by CYP2E1 Enzyme Activity: Inhibitory Effect of Cytochrome P450 Enzyme CYP2E1 by Salicylic Acid in Rat Liver Microsomes

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 932
Author(s):  
Hassan Salhab ◽  
Declan P. Naughton ◽  
James Barker
Keyword(s):  
High Performance Liquid Chromatography ◽  
Enzyme Activity ◽  
Cytochrome P450 ◽  
Salicylic Acid ◽  
Liquid Chromatography ◽  
Drug Interactions ◽  
High Performance ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Rat Liver Microsomes

Inhibition of cytochrome P450 (CYP) alters the pharmacokinetic parameters of the drug and causes drug–drug interactions. Salicylic acid been used for the treatment of colorectal cancer (CRC) and chemoprevention in recent decades. Thus, the aim of this study was to examine the in vitro inhibitory effect of salicylic acid on CYP2E1 activity in rat liver microsomes (RLMs) using high-performance liquid chromatography (HPLC). High-performance liquid chromatography analysis of a CYP2E1 assay was developed on a reversed phase C18 column (SUPELCO 25 cm × 4.6 mm × 5 µm) at 282 nm using 60% H2O, 25% acetonitrile, and 15% methanol as mobile phase. The CYP2E1 assay showed a good linearity (R2 > 0.999), good reproducibility, intra- and inter-day precision (<15%), acceptable recovery and accuracy (80–120%), and low detection (4.972 µM and 1.997 µM) and quantitation limit values (15.068 µM and 6.052 µM), for chlorzoxazone and 6-hydroxychlorzoxazone, respectively. Salicylic acid acts as a mixed inhibitor (competitive and non-competitive inhibition), with Ki (inhibition constant) = 83.56 ± 2.730 µM and concentration of inhibitor causing 50% inhibition of original enzyme activity (IC50) exceeding 100 µM (IC50 = 167.12 ± 5.460 µM) for CYP2E1 enzyme activity. Salicylic acid in rats would have both low and high potential to cause toxicity and drug interactions with other drugs that are substrates for CYP2E1.

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