The cytochrome P450 (CYP) 3A subfamily is estimated to participate in the biotransformation of 50% of the currently prescribed drugs. Four members of the CYP3A subfamily have been identified in humans: CYP3A4, CYP3A5, CYP3A7, and CYP3A43. Initial data suggested that CYP3A5 accounts for only a small proportion of the total hepatic CYP3A in about 20% of samples, but it was later revealed that CYP3A5 represents more than 50% of the total CYP3A amount in some individuals. Several genetic variants have been described for the CYP3A5 gene, of which the CYP3A5*3 allele (gA6986G), the most common form and leading to the loss of CYP3A5 activity, has been extensively investigated in the aspect of pharmacokinetics and disease risk. This review summarized the molecular characteristics of the CYP3A5 gene, and discusses the association of the CYP3A5*3 polymorphism with disease risks such as cancer and hypertension, along with its role in the pharmacokinetics of CYP3A substrates.
Alleles ; Biotransformation ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System ; Humans ; Hypertension ; Pharmacogenetics ; Pharmacokinetics

Gukang Capsules are often used in combination with drugs to treat fractures, osteoarthritis, and osteoporosis. Cytochrome P450(CYP450) mainly exists in the liver and participates in the oxidative metabolism of a variety of endogenous and exogenous substances and serves as an important cause of drug-metabolic interactions and adverse reactions. Therefore, it is of great significance to study the effect of Gukang Capsules on the activity and expression of CYP450 for increasing its clinical rational medication and improving the safety of drug combination. In this study, the Cocktail probe method was used to detect the changes in the activities of CYP1A2, CYP3A2, CYP2C11, CYP2C19, CYP2D4, and CYP2E1 in rat liver after treatment with high-, medium-and low-dose Gukang Capsules. The rat liver microsomes were extracted by the calcium chloride method, and protein expression of the above six CYP isoform enzymes was detected by Western blot. The results showed that the low-dose Gukang Capsules could induce CYP3A2 and CYP2D4 in rats, medium-dose Gukang Capsules had no effect on them, and high-dose Gukang Capsules could inhibit them in rats. The high-dose Gukang Capsules did not affect CYP2C11 in rats, but low-and medium-dose Gukang Capsules could induce CYP2C11 in rats. Gukang Capsules could inhibit CYP2C19 in rats and induce CYP1A2 in a dose-independent manner, but did not affect CYP2E1. If Gukang Capsules were co-administered with CYP1A2, CYP2C19, CYP3A2, CYP2C11, and CYP2D4 substrates, the dose should be adjusted to avoid drug interactions.
Rats ; Animals ; Cytochrome P-450 CYP1A2/metabolism* ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP2E1/pharmacology* ; Rats, Sprague-Dawley ; Cytochrome P-450 Enzyme System/metabolism* ; Microsomes, Liver ; Liver ; Cytochrome P-450 CYP3A/metabolism*

Flavonoids are present in fruits, vegetables and beverages derived from plants, and in many dietary supplements or herbal remedies. A number of naturally occurring flavonoids have been shown to modulate the CYP450 system, including the induction or inhibition of these enzymes. This review focuses on the flavonoid effects on cytochrome P450 (CYP) enzyme CYP1, 2E1, 3A4 and 19. Flavonoids alter CYPs by various mechanisms, including the stimulation of gene expression via specific receptors and/or CYP protein, or mRNA stabilization and so on. But in vivo and in vitro, the effects of flavonoids are not always coincident as a result of concentrations of flavonoids, genetic and environmental factors. As well, flavonoids may interact with drugs through the induction or inhibition of their metabolism. Much attention should be paid to the metabolism interaction of the flavonoids when coadministered with other drugs.
Animals ; Aromatase ; genetics ; metabolism ; Cytochrome P-450 CYP1A1 ; antagonists & inhibitors ; genetics ; metabolism ; Cytochrome P-450 CYP2E1 ; genetics ; metabolism ; Cytochrome P-450 CYP2E1 Inhibitors ; Cytochrome P-450 CYP3A ; genetics ; metabolism ; Cytochrome P-450 CYP3A Inhibitors ; Cytochrome P-450 Enzyme Inhibitors ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Enzyme Activation ; drug effects ; Flavonoids ; pharmacology ; Humans ; RNA, Messenger ; genetics ; metabolism

The incidence of polypharmacy-which can result in drug-drug interactions-has increased in recent years. Drug-metabolizing enzymes and drug transporters are important polypharmacy modulators. In this study, the effects of bosentan and rifampin on the expression and activities of organic anion-transporting peptide (OATP) and cytochrome P450 (CYP450) 2C9 and CYP3A4 were investigated in vitro. HEK293 cells and primary human hepatocytes overexpressing the target genes were treated with bosentan and various concentrations of rifampin, which decreased the uptake activities of OATP transporters in a dose-dependent manner. In primary human hepatocytes, CYP2C9 and CYP3A4 gene expression and activities decreased upon treatment with 20 μM bosentan+200 μM rifampin. Rifampin also reduced gene expression of OATP1B1, OATP1B3, and OATP2B1 transporter, and inhibited bosentan influx in human hepatocytes at increasing concentrations. These results confirm rifampin- and bosentan-induced interactions between OATP transporters and CYP450.
Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System* ; Cytochromes* ; Gene Expression ; HEK293 Cells ; Hepatocytes* ; Humans* ; In Vitro Techniques ; Incidence ; Organic Anion Transporters ; Polypharmacy ; Rifampin*

Scutellaria baicalensis is one of the most widely used herbal medicines in East Asia. Because baicalein and baicalin are major components of this herb, it is important to understand the effects of these compounds on drug metabolizing enzymes, such as cytochrome P450 (CYP), for evaluating herb-drug interaction. The effects of baicalin and baicalein on activities of ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), benzyloxyresorufin O-debenzylase (BROD), p-nitrophenol hydroxylase and erythromycin N-demethylase were assessed in rat liver microsomes in the present study. In addition, the pharmacokinetics of caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) in baicalin-treated rats were compared with untreated control. As results, EROD, MROD and BROD activities were inhibited by both baicalin and baicalein. However, there were no significant differences in the pharmacokinetic parameters of oral caffeine and its three metabolites between control and baicalin-treated rats. When the plasma concentration of baicalin was determined, the maximum concentration of baicalin was below the estimated IC50 values observed in vitro. In conclusion, baicalin had no effects on the pharmacokinetics of caffeine and its metabolites in vivo, following single oral administration in rats.
Administration, Oral ; Animals ; Caffeine* ; Cytochrome P-450 CYP1A1 ; Cytochrome P-450 CYP2B1 ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System ; Drug Interactions ; Far East ; Herb-Drug Interactions ; Inhibitory Concentration 50 ; Microsomes, Liver ; Pharmacokinetics* ; Plasma ; Rats* ; Scutellaria baicalensis ; Theobromine

<p>AIMTo identify the drug-metabolizing enzymes involved in the hydroxylation of the new anti-inflammatory and anodyne imrecoxib.p><p>METHODSImrecoxib was incubated with heterologous expression human cytochrome P450 (rCYPs) in vitro, and metabolites and remained parent drug were detected with liquid chromatography-multistage mass spectrometry. The contribution of 4 CYPs in the hydroxylation metabolism of imrecoxib was evaluated by total normalized rate (TNR) method.p><p>RESULTSImrecoxib is metabolized by CYP2C9, CYP2D6 and CYP3A4, with the rate of 62.5%, 21.1% and 16.4%, respectively.p><p>CONCLUSIONCYP2C9 is the major enzyme involved in imrecoxib hydroxylation metabolism.p>
Aryl Hydrocarbon Hydroxylases ; metabolism ; Cyclooxygenase 2 Inhibitors ; metabolism ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP2D6 ; metabolism ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System ; metabolism ; Hydroxylation ; Pyrroles ; metabolism ; Spectrometry, Mass, Electrospray Ionization ; Sulfides ; metabolism

<p>OBJECTIVETo establish a convenient and efficient model for investigating the expression of CYP3A4 and drug metabolism in vitro.p><p>METHODS1alpha,25-dihydroxyvitamin D3 was utilized as an inducer to enhance CYP3A4 expression in HepG2 cells. 0.1, 0.25, 0.35 micromol/L 1alpha,25-dihydroxyvitamin D3 were added to the cell culture media, and cells were harvested after 24, 48, 72 and 96 hours. Cell proliferation was determined with MTT assay. CYP3A4 mRNA level was analyzed with RT-PCR and expressions of CYP3A4 protein were measured by Western blot.p><p>RESULTS1alpha,25-dihydroxyvitamin D3 in 3 concentrations, namely 0.10, 0.25 and 0.35 micromol/L, did not show obvious toxicity to HepG2 cells. At 24 h of the cultivation, the expression of CYP3A4 mRNA was not increased significantly, but CYP3A4 mRNA expression significantly increased by 120%, 134%, 200% at 48 h, by 174%, 254%, 420% at 72 h, and by 258%, 450%, 370% at 96 h, respectively under the three concentrations. Similar results were observed in the induction of CYP3A4 protein expression. At 48, 72 and 96 hours after treatment with 0.25 micromol/L and 0.35 micromol/L 1alpha,25-dihydroxyvitamin D3, CYP3A4 protein increased in various folds in the controls (1.2 and 2.2 after 48 h, 3.4 and 6.5 after 72 h, 6.1 and 7.2 after 96 h), while 0.10 micromol/L 1alpha,25-dihydroxyvitamin D3 only induced protein expression at 72 h and 96 h (1.8 and 4.1 folds, respectively).p><p>CONCLUSION1alpha,25-dihydroxyvitamin D3 could induce the expression of CYP3A4 mRNA as well as CYP3A4 protein in HepG2, which provides a convenient and efficient in vitro system for investigation of CYP3A4 and drug interaction.p>
Calcitriol ; pharmacology ; Cytochrome P-450 CYP3A ; drug effects ; genetics ; metabolism ; Hep G2 Cells ; Humans ; Transcription, Genetic

BACKGROUND/AIMS: The pharmacokinetics of tacrolimus (TAC) is known to be largely influenced by single-nucleotide polymorphisms (SNPs) in CYP3A5. Patients starting TAC require careful dose adjustment, owing to the wide range of optimal dosages, depending on their CYP3A5 expression status. Here, we evaluated whether individualization of TAC dosages based on CYP3A5 SNPs would improve its therapeutic efficacy in ulcerative colitis. METHODS: Twenty-one patients were prospectively treated, with their initial dosage adjusted according to their CYP3A5 status (0.1, 0.15, and 0.2 mg/kg/day for CYP3A5*3/*3, CYP3A5*1/*3, and CYP3A5*1/*1, respectively). Their clinical outcomes were compared with those of patients treated with a fixed dose (0.1 mg/kg/day). RESULTS: The first blood trough level of CYP3A5 expressors, CYP3A5*1/*3 or CYP3A5*1/*1, and the overall rate in achieving the target blood trough level within a week in the individualized-dose group were significantly higher than those in the fixed-dose group (5.15±2.33 ng/mL vs. 9.63±0.79 ng/mL, P=0.035 and 12.5% vs. 66.7%, P=0.01). The remission rate at 2 weeks in the expressors was as high as that in the nonexpressors, CYP3A5*3/*3, in the individualized-dose group. CONCLUSIONS: Individualized TAC treatment is effective against ulcerative colitis regardless of the CYP3A5 genotype.
Colitis, Ulcerative ; Cytochrome P-450 CYP3A ; Genotype ; Humans ; Pharmacokinetics ; Polymorphism, Single Nucleotide ; Prospective Studies ; Tacrolimus ; Ulcer

Rotundine (1 micromol L(-1)) was incubated with a panel of rCYP enzymes (1A2, 2C9, 2C19, 2D6 and 3A4) in vitro. The remained parent drug in incubates was quantitatively analyzed by an Agilent LC-MS. CYP2C19, 3A4 and 2D6 were identified to be the isoenzymes involved in the metabolism of rotundine. The individual contributions of CYP2C19, 3A4 and 2D6 to the rotundine metabolism were assessed using the method of total normalized rate to be 31.46%, 60.37% and 8.17%, respectively. The metabolites of rotundine in incubates were screened with ESI-MS at selected ion mode, and were further identified using MS2 spectra and precise molecular mass obtained from an Agilent LC/Q-TOF-MSMS, as well as MS(n) spectra of LC-iTrap-MS(n). The predominant metabolic pathway of rotundine in rCYP incubates was O-demethylation. A total 5 metabolites were identified including 4 isomerides of mono demethylated rotundine and one di-demethylated metabolite. The results also showed that CYP2C19, 2D6 and 3A4 mediated O-demethylation of methoxyl groups at different positions of rotundine. Furthermore, the ESI-MS cleavage patterns of rotundine and its metabolites were explored by using LC/Q-TOF-MSMS and LC/iTrap-MS(n) techniques.
Analgesics, Non-Narcotic ; metabolism ; Aryl Hydrocarbon Hydroxylases ; metabolism ; Berberine Alkaloids ; metabolism ; Chromatography, Liquid ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP2D6 ; metabolism ; Cytochrome P-450 CYP3A ; metabolism ; Cytochrome P-450 Enzyme System ; metabolism ; Dopamine Antagonists ; metabolism ; Humans ; Isoenzymes ; metabolism ; Methylation ; Recombinant Proteins ; metabolism ; Spectrometry, Mass, Electrospray Ionization

The present work was to study induction of cytochrome P450 (CYP)3A and CYP2H1 gene by reverse transcriptase polymerase chain reaction (RT-PCR) and quantitative RTPCR in Bantam, Bantamized White Leghorn and White Leghorn chicks. Out of 18 chicks total 3 from each group (Bantam, Bantamized White Leghorn and White Leghorn) were treated intraperitoneal with phenobarbital at the dose rate of 12 mg/100 g (body weight) while the control group was treated with the saline. Total RNA was extracted from the liver samples using Tri Reagent based method. First strand cDNA was synthesized using one step RT-PCR kit. The PCR was performed and the product was subjected to agarose gel electrophoresis. Quantitative RT-PCR was conducted to quantify gene expression level of CYP3A and CYP2H1 genes. Relative expression ratio of CYP3A and CYP2H1 genes was calculated using relative expression software tool (REST). It was found that CYP3A is up regulated by factor of 1.34, 14.51 and 1.00 in Bantam, Bantamized White Leghorn and White Leghorn chicks, respectively. In Bantam and Bantamized White Leghorn chicks CYP2H1 gene was up regulated by factor 1.50 and 80.87, respectively but down regulated by a factor of 1.97 in White Leghorn chicks. The PCR efficiency ranged from 1.30 to 1.70, 0.86 to 1.70 and 0.91 to 1.58 for CYP3A, CYP2H1 and beta-actin, respectively in Bantam, Bantamized White Leghorn and White Leghorn chicks.
Animals ; Chickens/*metabolism ; Cytochrome P-450 CYP3A/*biosynthesis/genetics ; Cytochrome P-450 Enzyme System/*biosynthesis/genetics ; Gene Expression Regulation/drug effects ; Phenobarbital/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction