• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1310-1316
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• 2005

To evaluate the toxicological properties of human cytochrome P450 2E1 (CYP2E1) induced by ethanol and possible protective effects of various green tea catechins on alcohol-induced toxicity, transfected HepG2 cells that stably and constitutively express human CYP2E1 were established using the recombinant retroviral expression vector. Exposure of the CYP2E1-expressing HepG2 cells to high concentration of ethanol (200 mM) for 5 days resulted in a more than $50\%$ increase of cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) production, and loss of normal morphology, in comparison with HepG2 cells containing control vector. Treatment of the cells with various catechins increased cell viability by more than 2-fold. (-)-Epicatechin gallate and(-)-catechin gallate at the lowest concentration ($5\;{\mu}M$) attenuated cell death induced CYP2E1 by $60-65\%$. Therefore, the results showed that the catechins, including epimerized catechins, have strong protective effects against alcohol-induced CYP2E1 toxicity, and it is correlated with antioxidant effect.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.498-503
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• 2011

The purpose of this study was to investigate the effects of nisoldipine on the pharmacokinetics of repaglinide in rats. The effect of nisoldipine on cytochrome P450 (CYP) 3A4 activity and P-glycoprotein (P-gp) were evaluated. The pharmacokinetic parameters of repaglinide were also determined in rats after oral (0.5 $mg{\cdot}kg^{-1}$) and intravenous (0.2 $mg{\cdot}kg^{-1}$) administration of repaglinide to rats without or with nisoldipine (0.3 and 1.0 $mg{\cdot}kg^{-1}$). Nisoldipine inhibited CYP3A4 enzyme activity with a 50% inhibition concentration of 5.5 ${\mu}M$. In addition, nisoldipine significantly enhanced the cellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. Compared to the oral control group, nisoldipine significantly increased the $AUC_{0-{\infty}}$ and the $C_{max}$ of repaglinide by 46.9% and 24.9%, respectively. Nisoldipine also increased the absolute bioavailability (A.B.) of repaglinide by 47.0% compared to the oral control group. Moreover, the relative bioavailability (R.B.) of repaglinide was 1.16- to 1.47-fold greater than that of the control group. Nisoldipine enhanced the oral bioavailability of repaglinide, which may be attributable to the inhibition of the CYP3A4-mediated metabolism in the small intestine and/or in the liver and to inhibition of P-gp in the small intestine rather than to reduction of renal elimination of repaglinide by nisoldipine. The increase in the oral bioavailability of repaglinide should be taken into consideration of potential drug interactions when co-administering repaglinide and nisoldipine.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.230-238
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• 2004

The adverse health effects of a number of environment pollutions are related to the formation of free radicals. Induction of antioxidant defensive system in the response to an oxidative attack is an essential element of the cell to survive. CYP2E1 is easily induced by organic solvents and induces continuous formation of reactive oxygen species (ROS). ${\gamma}$-Glutamyltranspeptidase (${\gamma}$GT) plays an important role in glutathione metabolism and xenobiotic detoxification. To evaluate the characteristic of oxidative stress which induces GGT expression and to understand human antioxidant defensive response against oxidative stress induced by CYP2E1, we studied regulation of ${\gamma}$GT enzyme expression in response to various oxidative stresses in human HepG2 cells. The ${\gamma}$GT activity was not modified after exposure of acute oxidative stress inducing agents (ferric nitrilotriacetate, cumene hydroperoxide, ADP-Fe, O-tetradecanoylphorbol-13-acetate, tumor necrosis factor-alpha). To induce continuous exposure of cells to ROS, HepG2 cells were transfected by human CYP2E1 gene transiently. The CYP2E1 activity was verified with chlorzoxazone hydroxylation. Transfection of CYP2E1 showed continuous 60% increase in intracellular ROS and 240 % increase in microsomal ROS. CYP2E1 overexpressing cells showed increased ${\gamma}$GT activity (2.5-fold). The observed enhancement of ${\gamma}$GT activity correlated with a significant increase of ${\gamma}$GT mRNA (2.1-fold). Treatment with antioxidant strongly prevented the increase in ${\gamma}$GT activity. The CYP2E1 overexpression did not modify toxicity index and increased glutathione levels. These results show that continuous exposure of cells to ROS produced by CYP2E1 up-regulates ${\gamma}$GT; This may be one of the adaptive antioxidant responses of cells to oxidative insult. Present study also suggests that the induction of ${\gamma}$GT could be used as a marker of oxidative stress induced by exposure to organic solvents.

• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.568-578
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• 2001

Background : Lung cancer is frequently cited as an example of a disease caused solely by exposure to environmental carcinogens. However, there is a growing realization that the genetic constitution is also important in determining individual's susceptibility to lung cancer. This genetic susceptibility may result from functional polymorphims of the genes involved in carcinogen metabolism. In this study, the association between GSTM1 and CYP1A1 polymorphisms and the lung cancer risk in Korean males was investigated. Materials and Method : The study population consisted of 153 male lung cancer patients and 143 healthy male controls. The GSTM1 and CYP1A1 genotypes were determined by multiplex PCR and PCR-RFLP analysis. Result : There were no significant differences in the frequency of the GSTM1 null genotype between the cases and the controls. When the cases were categorized by their histologic type, the frequency of the GSTM1 null genotype in the small cell carcinoma group was higher than those of the controls(67.2% vs 55.9%), but the difference was not statistically significant(OR=1.772 ; 95% CI=0.723-4.340). The distribution of the CYP1A1 MspI genotypes among the cases were similar to those among the controls. When the cases were grouped by their histologic type, the ml/m1, ml/m2, m2/m2 genotypes frequencies among the small cell carcinomas(23.0%, 38.5%, and 38.5%, respectively) were significantly different from those of the controls(36.4%, 46.2%, and 7.4%, respectively, p<0.05). When the m1/m1 genotype was used as a reference, the ml/m2 and m2/m2 genotypes were associated with an increased risk for small cell lung cancer(ml/m2 genotype : OR=1.337, 95% CI=0.453-3.947 ; m2/m2 genotype : OR=3.374, 95% CI=1.092-10.421). Conclusion : These results suggest that the GSTM1 and CYP1A1 genotypes may be a genetic determinant of the risk for lung cancer, particlulary small cell carcinoma. Further investigation is needed to confirm these results.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.498-502
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• 2016

3'-Hydroxygenistein can be obtained from the biotransformation of genistein by the engineered Pichia pastoris X-33 strain, which harbors a fusion gene composed of CYP57B3 from Aspergillus oryzae and a cytochrome P450 oxidoreductase gene (sCPR) from Saccharomyces cerevisiae. P. pastoris X-33 mutants with higher 3'-hydroxygenistein production were selected using a periodic hydrogen peroxide-shocking strategy. One mutant (P2-D14-5) produced 23.0 mg/l of 3'-hydroxygenistein, representing 1.87-fold more than that produced by the recombinant X-33. When using a 5 L fermenter, the P2-D14-5 mutant produced 20.3 mg/l of 3'-hydroxygenistein, indicating a high potential for industrial-scale 3'-hydroxygenistein production.

• Clinical and Experimental Pediatrics
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• v.48 no.4
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• pp.380-386
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• 2005

Purpose : The incidence of nonphysiologic neonatal hyperbilirubinemia is twice as high in East Asians as in whites. Recently, UGT1A1 mutation was found to be a risk factor for neonatal hyperbilirubinemia. In congenitally-jaundiced Gunn rats, which lack expression of UDP-glucuronosyltransferase, alternative pathways can be stimulated by inducers of CYP1A1 and CYP1A2 enzymes. CYP1A2 plays a major role in bilirubin degradation of the alternate pathway. We studied the relationship between UGT1A1 and CYP1A2 gene polymorphism of neonatal hyperbilirubinemia in Koreans. Methods : Seventy-nine Korean full term neonates who had hyperbilirubinemia(serum bilirubin >12 mg/dL) without obvious causes of jaundice, were analyzed for UGT1A1 and CYP1A2 gene polymorphism; the control group was sixty-eight. We detected the polymorphism of Gly71Arg of UGT1A1 gene by direct sequencing and T2698G of CYP1A2 by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) using MboII and direct sequencing. Results : Allele frequency of Gly71Arg mutation in the hyperbilirubinemia group was 32 percent, which was significantly higher than 11 percent in the control group(P<0.0001). Mutant gene frequency of T2698G was 41.8 percent in patients and 32.3 percent in the control group(P=0.015), but allele frequency was 21 percent in patients and 19 percent in the control group, which was not significantly higher(P=0.706). There was no relationship between mutations of two genes(P=0.635). Conclusion : The polymorphism of UGT1A1 gene(Gly71Arg) and CYP1A2 gene(T2698G) was detected in Korean neonatal hyperbilirubinemia. Only polymorphisms of Gly71Arg in UGT1A1 were significantly higher than control group.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.109-114
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• 2008

To evaluate the extent of Sea-Nine 211 (4,5-dichloro-2-n-octyl-3(2H) isothiazolone), one of the alternating organic booster compound used in antifouling paint to replace TBT, on marine benthic bivalve, we injected Sea-Nine 211 to clam, Pseudocardium sachalinensis, and then determined some xenobiotics metabolizing enzyme activities, especially EROD (ethoxyresorufin deethylase) and MROD (methoxyresorufin demethylase), in digestive gland during 4 day-exposure period. Moreover, the results were compared with those of TBT exposed clam. CYP1A1 dependant EROD activity in both the Sea-Nine 211 and the TBTC exposure groups showed no significant differences compared to those of the solvent control group. CYP1A2 dependant MROD activity in Sea-Nine 211 exposure group was significantly induced, but no significant difference was obtained in the TBTC exposure group. These results indicate that Sea-Nine 211 demonstrated a tendency to induce MROD activity, while TBTC inhibits the activities of this enzyme.

• Korean Journal of Clinical Pharmacy
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• v.20 no.1
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• pp.25-29
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• 2010

The purpose of this study was to investigate the effect of atorvastatin on the pharmacokinetics of nifedipine (6 mg/kg) after oral administration of nifedipine with or without atorvastatin (0.5 and 2.0 mg/kg) in rats, and also was to evaluate to the effect of atorvastatin on the CYP3A4 activity. The 50% inhibiting concentration ($IC_{50}$) values of atorvastatin on CYP3A4 activity is 46.1 ${\mu}M$. Atorvastatin inhibited CYP3A4 enzyme activity in a concentration-dependent manner. Coadministration of atorvastatin increased significantly (p<0.05, 2.0 mg/kg) the plasma concentration-time curve (AUC) and the peak concentration ($C_{max}$) of nifedipine compared to the control group. The relative bioavailability (RB%) of nifedipine was increased from 1.15- to 1.37-fold. Coadministration of atorvastatin did not significantly change the terminal half-life ($T_{1/2}$) and the time to reach the peak concentration ($T_{max}$) of nifedipine. Based on these results, we can make a conclusion that the significant changes of these pharmacokinetic parameters might be due to atorvastatin, which possesses the potency to inhibit the metabolizing enzyme (CYP3A4) in the liver and intestinal mucosa, and also inhibit the P-glycoprotein (P-gp) efflux pump in the intestinal mucosa. It might be suggested that atorvastatin altered disposition of nifedipine by inhibition of both the first-pass metabolism and P-glycoprotein efflux pump in the small intestine of rats. In conclusion, the presence of atorvastatin significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of atorvastatin with nifedipine should require close monitoring for potential drug interation.

• YAKHAK HOEJI
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• v.54 no.4
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• pp.252-257
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• 2010

The aim of this study was to investigate the effect of resveratrol on the pharmacokinetics of nifedipine in rats. The pharmacokinetic parameters of nifedipine were measured after the oral administration of nifenipine (6 mg/kg) in the presence or absence of resveratrol (0.5, 2.5 and 10 mg/kg, respectively). The effect of resveratrol on the P-glycoprotein (Pgp), CYP 3A4 activity was also evaluated. Resveratrol inhibited CYP3A4 enzyme activity in a concentration-dependent manner with 50% inhibition concentration ($IC_{50}$) of 0.94 ${\mu}M$. In addition, resveratrol significantly enhanced the cellular accumulation of rhodamine 123 in MCF-7/ADR cells overexpressing P-gp. Compared to the control groups, the presence of 2.5 mg/kg and 10 mg/kg of resveratrol significantly (p<0.05, p<0.01) increased the area under the plasma concentrationtime curve (AUC) of nifedipine by 49~75%, and the peak concentration ($C_{max}$) of nifedipine by 48~66%. The absolute bioavailability (AB%) of nifedipine was significantly (p<0.05) increased by 22.9-34.8% compared to the control (19.8%). The terminal half-life ($T_{1/2}$) of nifedipine was significantly (p<0.05) increased compared to the control. While there was no significant change in the time to reach the peak plasma concentration ($T_{max}$) of nifedipine in the presence of resveratrol. It might be suggested that resveratrol altered disposition of nifedipine by inhibition of both the CYP3A and P-glycoprotein efflux pump in the small intestine of rats. In conclusion, the presence of resveratrol significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of resveratrol or resveratrol-containing dietary supplenment with nifedipine should require close monitoring for potential drug interation.

• Mass Spectrometry Letters
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• v.7 no.3
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• pp.69-73
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• 2016

High-resolution quadrupole-Orbitrap mass spectrometry (HRMS), with high-resolution (> 10,000 at full-width at half-maximum) and accurate mass (< 5 ppm deviation) capabilities, plays an important role in the structural elucidation of drug metabolites in the pharmaceutical industry. ML106, a derivative of imidazobenzimidazole, decreased melanin content and tyrosinase activity in a dose-dependent manner. Here, we investigated the phase 1 metabolic pathway of ML106 using HRMS in human liver microsomes (HLMs) and recombinant cDNA-expressed cytochrome P450 (CYP). After the incubation of ML106 with pooled HLMs and recombinant cDNA-expressed CYP in the presence of NADPH, five phase 1 metabolites, including three mono-hydroxylated metabolites (M1-3) and two di-hydroxylated metabolites (M4 and M5), were investigated. The metabolite structures were postulated by the elucidation of protonated mass spectra using HRMS. The CYP isoforms related to the hydroxylation of ML106 were studied after incubation with recombinant cDNA-expressed CYP. Here, we identified the phase 1 metabolic pathway of ML106 induced by CYP in HLMs.