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

<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

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

<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

Cytochrome P450 enzymes are composed of many isozymes and involved in the biotransformation of both exogenous and endogenous substances. A growing number of studies have found that the P450 enzymes do not always follow the classical Michaelis-Menten kinetics, but show atypical kinetic behavior, which is also the current research hotspot. In this paper, the category and mechanisms of atypical kinetics of the P450 enzyme were reviewed, providing theoretical basis for the research of enzyme kinetics.
Animals ; Benzoflavones ; pharmacology ; Binding Sites ; Cytochrome P-450 CYP3A ; chemistry ; metabolism ; Cytochrome P-450 Enzyme System ; chemistry ; metabolism ; Enzyme Activation ; Humans ; Kinetics ; Protein Binding ; Substrate Specificity

<p>OBJECTIVETo investigate the changes in hepatic functions and activities of CYP1A2 and CYP3A4 in rats after acute exposure to high altitude.p><p>METHODSTwelve healthy male Wistar rats were randomly divided into control group and exposure group for acute exposure to normal and high altitude (4010 m) environment. Blood samples were collected from the vena orbitalis posterior for detection of the hepatic function. Hepatic pathologies of the rats were examined microscopically with HE staining. Liver microsomes were extracted by differential centrifugation to assess the activities of CYP1A2 and 3A4 using P450-GloTM kit.p><p>RESULTSIn rats with acute exposure to high altitude, AST, ALT, and ALP all increased significantly by 48.50%, 47.90%, and 103.02%, respectively, and TP decreased significantly by 17.80% as compared with those in rats maintained in normal altitude environment (P<0.05). Pathological examination of the liver revealed edema of the central vein of the liver and hepatocyte karyopyknosis in rats after acute exposure to high altitude, which also resulted in significantly lowered activities of CYP1A2 and 3A4 in the liver (by 96.56% and 43.53%, respectively).p><p>CONCLUSIONAcute exposure to high altitude can cause obvious liver injuries and lowered activities of CYP1A2 and 3A4 in rats to severely affect drug metabolism in the liver and result in increased concentration, prolonged half-life and reduced clearance of drugs.p>
Altitude ; Animals ; Cytochrome P-450 CYP1A2 ; Cytochrome P-450 CYP3A ; metabolism ; Cytochromes ; metabolism ; Liver ; pathology ; Male ; Microsomes, Liver ; enzymology ; Rats ; Rats, Wistar

<p>OBJECTIVETo observe the effect of ketoconazole on the activity of cytochrome P450 (CYP) 1A2 and 3A4 in hepatic microsomes of healthy adults.p><p>METHODSHuman hepatic microsomes obtained from healthy adults were randomly divided into control group and ketoconazole-treatment groups at different concentrations. After 15 min of culture, the substrates (testosterone for CYP3A4 and phenacetin for CYP1A2) were added and incubated for another 20 min. The metabolites (6-testosterone and acetaminophen) were then measured with high-performance liquid chromatography (HPLC) to assess the activities of CYP3A4 and 1A2.p><p>RESULTSSignificant difference was found between the groups in the quantity of 6-testosterone and the relative activity of CYP3A4 (P<0.05). The IC(50) of ketoconazole for CYP3A4 was 0. 16 mg/L. Both the quantity of 6-testosterone and the relative activity of CYP3A4 were reduced gradually with the increment of ketoconazole concentration. Significant differences were found between the ketoconazole groups and the control group in both the quantity of acetaminophen and the relative activity of CYP1A2 (P<0.05). Ketoconazole at low doses reduced CYP1A2 activity and but increased the activities at high doses (P<0.05).p><p>CONCLUSIONIn the range of maximum clinical blood concentration, ketoconazole can inhibit the activity of CYP3A4, but not that of CYP1A2, in the hepatic microsomes in healthy adults.p>
Adult ; Antifungal Agents ; pharmacology ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP3A ; metabolism ; Dose-Response Relationship, Drug ; Female ; Humans ; Ketoconazole ; pharmacology ; Male ; Microsomes, Liver ; drug effects ; enzymology

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

<p>OBJECTIVETo establish a RP-HPLC method for the determination of amlodipine after metabolism by cytochrome P450 cDNA-expressed cells.p><p>METHODSThe determination was performed on a C(18) reversed phase column with a mobile phase composed of acetonitrile phosphates buffer (45:55, v/v, pH 4.5) with UV detection (lambda250nm). Propranolol was used as the internal standard.p><p>RESULTThe standard curve was linear over the concentration range of 0.2 - 30.0 microg/ml (r=0.9993), and the limits of determination was 20 ng/ml (S/N >or=3), the limits of quantity was 0.2 microg/ml (recovery 104.0%, RSD 11.4%, n=5). The recovery for this assay was (98.2+/-2.4)%, precision for inter-assay and intra-assay was <10 % and 6 %, respectively.p><p>CONCLUSIONThe HPLC method established is simple, accurate and suitable for the determination of amlodipine in cytochrome p450 cDNA-expressed cells.p>
Amlodipine ; analysis ; metabolism ; Calcium Channel Blockers ; analysis ; Chromatography, High Pressure Liquid ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System ; genetics ; physiology ; Humans ; Transfection