• Archives of Pharmacal Research
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• v.14 no.2
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• pp.130-136
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• 1991

Nicotine (100 .mu. M) was incubated with microsomes (1 mg/ml) prepared from New Zealand White rabbits. On the basis of microsomal weight, the rate of nicotine oxidation were calculated on the basis of cytochrome P-450 concentration, the specific activity of the metabolic oxidation catalyzed by lung was approximately 4 times greater than liver (6.4 vs 1, 65 nmoles nicotine oxidized. nmole cytochrome $P-450^{-1}\;min{-1})$. These studies employed several methods of altering activities of specific isozymes present in pulmonary microsomes, including the use of the isozyme2 and 6 specific inhibitor $\alpha$-methylbenzyl ABT, metabolite inhibitors, norbenzphetamine and N-hydroxyamphetamine. TCDD induction and Arochlor 1260 pretreatment. These results support the conclusion that nicotine metabolism by rabbit lung microsomes is mediated primarily by cytochrome P-450 isozyme 2.

• Toxicological Research
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• v.23 no.3
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• pp.189-196
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• 2007

Cytochrome P450 (P450) enzymes are the major catalysts involved in the biotransformation of various drugs, pollutants, carcinogens, and many endogenous compounds. Most of chemical carcinogens are not active by themselves but they require metabolic activation. P450 isozymes playa pivotal role in the metabolic activation. The activation of arylamines and heterocyclic arylamines (HAAs) involves critical N-hydroxylation, usually by P450. CYP1A2 plays an important role in these reactions. Broad exposure to many of these compounds might cause carcinogenicity in animals and humans. On the other hand, P450s can be also involved in the bioactivation of other chemicals including alcohols, aflatoxin B1, acetaminophen, and trichloroethylene, both in humans and in experimental animals. Understanding the P450 metabolic activation of many chemicals is necessary to develop rational strategies for prevention of their toxicities in human health. An important part is the issues of extrapolation between species in predicting risks and variation of P450 enzyme activities in humans.

• Journal of Society of Preventive Korean Medicine
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• v.16 no.3
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• pp.129-137
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• 2012

Objective : Herb-drug interactions have become an important issue because of the consumption of herbal remedies has increased in the world. Yangguksanhaw-tang (Liang ge san huo-tang) and Taeumjowi-tang (Tai yin tiao wei-tang) are typical herbal formulas on Sasang constitution medicine (four-constitution medicine). This study was aimed at evaluating the effects of Yangguksanhaw-tang and Taeumjowi-tang on drug metabolizing enzymes, cytochrome P450 (CYP450) isozymes. Methods : Vivid$^{(R)}$ CYP450 Screening Kits were used to measure of CYP3A4, CYP2C19, CYP2D6 and CYP2E1 activities. This method is based on the use of fluorescent CYP450 substrates that are efficiently metabolized by specific CYP450 isozymes to yield a product with altered fluorescent properties. The percent inhibitions of CYP450s by herbal formulas were calculated. Results : Yangguksanhaw-tang inhibited CYP2C19 and CYP2E1 activities higher than that other CYP450 isozymes. The $IC_{50}$ values of CYP2C19 and CYP2E1 were 159.83 ${\mu}g/mL$ and 261.40 ${\mu}g/mL$, respectively. The CYP2E1 activity was inhibited ($IC_{50}=215.17{\mu}g/mL$) higher than that other CYP450 isozymes by Taeumjowi-tang. Conclusions : These results suggest that Yangguksanhaw-tang may inhibit the metabolism of co-administered drugs whose primary route of metabolism is via CYP2C19 or CYP2E1. Taeumjowi-tang could inhibit the metabolism of co-administered drugs, which are substrates for CYP2E1. Therefore, co-administration of the herbal formulas and other conventional drugs should be undertaken with care.

• Journal of Sasang Constitutional Medicine
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• v.24 no.4
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• pp.84-91
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• 2012

Objectives : The purpose of this study is to investigate the inhibitory or inductive potentials of Yuldahanso-tang (YDT) and Chungsimyonja-tang (CST), herbal formulas for Taeeumin, on cytochrome P450 (CYP450) drug metabolizing enzyme. The mechanisms for the herbal formula-drug interaction has not been well reported in spite of the chance for co-administration with conventional drugs. Methods : To evaluate the interaction potential of YDT-drug or CST-drug, the fluorescence-based enzyme assays on CYP450 isozymes including CYP3A4, CYP2C19, CYP2D6 and CYP2E1 were established in vitro. The inhibitory effects of herbal formulas were characterized with $IC_{50}$ values. Results : YDT showed inhibitory effects on CYP2D6 and CYP2E1-mediated metabolism, while it exhibited week inhibition on CYP3A4 and CYP2C19 relatively. CST exerted relatively weak inhibitory effects on the four CYP450 isozymes compared to that of YDT. Conclusions : These results suggest that the herbal formula-drug interaction could be occur when YDT are co-administered with drugs mediated by CYP2D6 or CYP2E1.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.183-187
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• 2005

Abstract The cancer chemopreventive potential of chitosanoligosaccharides was investigated by measuring the induction of quinone reductase and glutathione S-transferase activities and inhibition of cytochrome P450 1A1, 2B1, and 2E1 activities. Chitosanoligosaccharide I (1-${\kappa}$Da${\kappa}$Da) significantly induced glutathione S-transferase activity with a maximal 1.5-fold increase at 500 ${\mu}$g/ml, while chitosanoligosaccharide II (3-${\kappa}$Da${\kappa}$Da) (500 ${\mu}$g/ml) strongly induced quinone reductase (p<0.01) and glutathione S-transferase (p<0.005) activities. The in vitro incubation of rat liver microsomes with chitosanoligosaccharides I and II (2.5, 5, 50, and 500 ${\mu}$g/ml) showed a dose-dependent inhibiton of cytochrome P450 1A1, 2B1, and 2E1 activities. Chitosanoligosaccharide II was a more potent inhibitor of cytochrome P450 2B1 activity than chitosanoligosaccharide I. Accordingly, these findings suggest that chitosanoligosaccharides are potential chemopreventive agents.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.168-173
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• 1995

To investigate the effects of endosulfan on cytochrome P-450 enzymes in mouse(Balb c.), endosulfan was given by an intraperitoneal dose of 7.5 mg/kg. The treatment of endosulfan increased the cytochrome P-450 content by 3.3 to 4.2 fold, cytochrome $b_5$ content by 2.3 to 3.8 fold, NADPH cytochrome P-450 reductase activity by 5.3 to 6.4 fold and total haem content by 3.1 to 3.6 fold of mouse liver after 48 hrs of intraperitoneal injection. Endosulfan cytochrome P-450 absorption spectrum exhibited miximum at 387 nm and 389 nm and broad near 407 nm in the liver microsome. Reduced P-450-CO spectrum of the liver microsome exposed by the treatment of endosulfan showed maximum at 449 nm and 450 nm compared to that of the control having maximum at 451 nm, which indicated endosulfan induced cytochrome P-450 new isozymes. Aldrin epoxidase activities in the mouse liver and kidney were increased by 2.8 and 2.1 fold by the treatment of endosulfan. Also 7-ethoxyresorufin dealkylase activities in the mouse liver and kidney were elevated by 1.7 and 1.8 fold by treatment of endosulfan.

• Toxicological Research
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• v.7 no.1
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• pp.1-12
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• 1991

The phenotyping of cytochrome P-450 in hepatic mivrosomes induced by phenytoin in the rats was carried out by using several monoclonal antibodies (MAbs) against specific P-450 isozymes. Phenytoin (180 mg/kg) was administered intrapritoneally for three consecutive days to the male Sprague-Dawley rats(100-120g). Solid phase radio-immunoassay showed higher binding affinity of MAb PB 2-66-3 and PCN 2-13-1 to the microsomes from phenytoin treated rats than those to from untreated rats, which was comparable to the level in phenobarbital induced rat hepatic microsomes.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.394-404
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• 2003

Certain polycyclic aromatic hydrocarbons (PAHs) have been reported to induce cytochrome P450 (CYP) 1A1 and 1A2. In the present study, the effects of six well-known PAHs, such as benzo[a]pyrene, benz[a]anthracene, dibenz[a,h]anthracene, chrysene, benzo[k]fluorancene and benzo[b]fluorancene, on the activities of hepatic and pulmonary CYP enzymes were investigated in male ICR mice. When mice were treated intraperitoneally with 3, 10 and 30 mg/kg of individual PAHs for 3 consecutive days, the activities of ethoxyresorufin- and methoxyresorufin-Ο-dealkylases were significantly and differentially induced in both liver and lung. Moreover, other CYP isozyme-associated monooxygenase activities were also induced significantly in liver and lung with characteristic induction profiles. Our present results suggest that individual PAHs might have inductive effects on CYP isozymes, and that the characteristic inductive effects of individual PAHs on certain CYP isozymes would be developed as a marker for determining exposure to certain PAHs.

• Food Science and Biotechnology
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• v.14 no.2
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• pp.297-300
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• 2005

Effects of allyl sulfides on kinetic behavior of cytochrome P450 1 (CYP1)-catalyzed ethoxyresorufin O-deethylase (EROD) activity were studied using microsomes from benzo[a]pyrene-treated human hepatoma cells. Apparent $K_m$ and $V_{max}$ values were calculated as $2.8\;{\mu}M$ and $3.0\;{\mu}mol$ resorufin/min/mg protein based on Lineweaver-Burk plot of microsomal EROD activity, respectively. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) affected $K_m$ and $V_{max}$ values of EROD activity and acted as mixed-type inhibitors for CYP1 isozymes. Apparent Ki values of DADS and DATS were calculated as 1.07 and 0.88 mM, respectively, by re-plotting slopes of Lineweaver-Burk plot and inhibitor concentrations.

• Analytical Science and Technology
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• v.5 no.1
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• pp.83-90
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• 1992

The $^{14}C$-warfarin used as rodenticids was identified from various organs of sprague dawley with scintillation counter. And the cytochrome p-450 which was induced by coumarin derivatives was identified with electrophoresis. The distributions of $^{14}C$-warfarin after $14.8{\mu}Ci/kg$ oral application at each organ was as follows; urine-7.5%, blood-0.44%, feces-0.9%, liver-0.66%, lung-0.86%, kidney-0.8%, heart-0.43% and spreen-0.33% after 24hrs. The cytochrome p-450 was purified by Octyl Sepharose CL-4B hydrophobic chromatography and isozymes were 50.8 Kd in control group, 53.3 Kd and 55.2 Kd in coumarin pretreated group and 50.8 Kd, 54.6 Kd and 57.7 Kd in warfarin pretreated group.