• Toxicological Research
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• 제15권1호
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• pp.95-101
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• 1999

Cytochrome P450 (CYP) 3A4 metabolizes aflatoxin B1 (AFB1) to AFB1-exo-8,9-epoxide (8,9-epoxidation) and aflatoxin Q1 (AFQ1; 3$\alpha$-hydroxylation) simultaneously. We investigated whether each metabolite was formed via its own binding site of CAP3A4 active site. Kinetics of the formation of the two metabolites were sigmoidal and consistent with the kinetics of substrate activation. The HIll model predicted that two substrate binding wites are involved in the oxidationof AFB1 by CYP3A4. Dehydronifedipine, a metabolite of nifedipine generated by CYP3A4, inhibited the formation of AFQ1 without any inhibition in the formation of AFB1-exo-8,9-epoxidation. Dehydronifedipine was found to act as a reversible competitive inhibitor against 3$\alpha$-hydroxylation of AFB1. Vmax and S0.5 of the 8,9-epoxidation were not changed in the presence of 0, 50, or 100 $\mu\textrm{M}$ dehydronifedipine. S0.5 of 3$\alpha$-hydroxylation was increased from 58$\pm$4 $\mu\textrm{M}$ to 111$\pm$8 $\mu\textrm{M}$ in the presence of 100 $\mu\textrm{M}$ nifedipine whereas Vmax was not changed. These results suggest that there exist two independent binding sites in the active site of CAP3A4 . One binding site is responsible for AFB1-exo-8,9-epoxidation and the other is involved in 3$\alpha$-hydroxylation of AFB1. Dehydronifedipine might selectively bind to the site which is responsible for the formation of AFQ1 in the active site of CYP3A4.

• 대한한의학회지
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• 제35권2호
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• pp.47-59
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• 2014

Objectives: Most drug interactions are attributed to the inhibition or induction of the activity of cytochrome P450s (CYP450). Although the regulation of CYP450s by drugs has been widely reported, there have been few studies on influence of traditional herbal formulas on the drug-metabolizing enzymes. Because herbal formulas have been used traditionally to treat various diseases and because herb-drug interactions are crucial factors determining therapeutic efficacies, a systematic evaluation of the effects of herbal formulas is important. Methods: The effects of Galgeun-tang (GGT, gegen tang), Gumiganghwal-tang (GMGHT, jiuweiqianghuo tang), Insampaedok-san (ISPDS, renshenbaidu powder), Samsoeum (SSE, shensu drink), Socheongryong-tang (SCRT, xiaoqinglong-tang) and Sosiho-tang (SSHT, xiaochaihu tang) that are traditional herbal formulas used to treat common cold, on drug-metabolizing enzymes were evaluated through an in vitro CYP3A4, CYP2D6, CYP2C19 and CYP2E1 inhibition assay to assess its interaction potential with synthetic drugs. The inhibitory effects of herbal formulas were characterized with $IC_{50}$ values. Results: These six herbal formulas inhibited the activities of CYP3A4, 2C19, 2D6 and 2E1, in a concentration-dependent manner. Among the six herbal formulas, GGT critically inhibited CYP2C19, CYP2D6 and CYP2E1. GMGHT also inhibited CYP2D6 and CYP2E1 to a greater extent than the other CYP450 isozymes. Additionally, SSE and SSHT may change the effects of medicines that depend primarily on the CYP2C19 and CYP2E1 pathways. On the other hand, ISPDS and SCRT were not inhibited CYP3A4, CYP2C19, CYP2D6 and CYP2E1-mediated metabolism. Conclusions: These findings provide useful information regarding the safety and effectiveness of herbal formulas.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2647-2653
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• 2012

Involvement of cytochrome P450 genes (CYPs) in breast cancer (BCa) may differ between populations, with expression patterns affected by tumorigenesis. This may have an important role in the metabolism of anticancer drugs and in the progression of cancer. The aim of this study was to determine the mRNA expression patterns of four cytochrome P450 genes (CYP2W1, 3A5, 4F11 and 8A1) in Mexican women with breast cancer. Real-time PCR analyses were conducted on 32 sets of human breast tumors and adjacent non-tumor tissues, as well as 20 normal breast tissues. Expression levels were tested for association with clinical and pathological data of patients. We found higher gene expression of CYP2W1, CYP3A5, CYP4F11 in BCa than in adjacent tissues and only low in normal mammary glands in our Mexican population while CYP8A1 was only expressed in BCa and adjacent tissues. We found that Ki67 protein expression was associated with clinicopathological features as well as with CYP2W1, CYP4F11 and CYP8A1 but not with CYP3A5. The results indicated that breast cancer tissues may be better able to metabolize carcinogens and other xenobiotics to active species than normal or adjacent non-tumor tissues.

• 한국해양생명과학회지
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• 제8권2호
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• pp.104-114
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• 2023

플라스틱은 전세계적으로 사용량이 증가함에 따라 해양 환경으로 유입되는 플라스틱 쓰레기의 양도 꾸준히 증가하고 있으며, 미세플라스틱은 해양 생물에 의해 섭취되어 소화관에 축적됨에 따라 성장과 생식에 유해한 영향을 미친다. Cytochrome P450 (CYP)는 환경 오염물질을 대사하는 해독효소로 알려져 있으나 지각류에서는 그 기능에 대해서는 잘 알려져 있지 않다. 본 연구에서는 기수산 물벼룩 Diaphanosoma celebensis에서 clan 2, 3, 4에 각각 속하는 CYP 유전자 9종(clan 2: CYP370A4, CYP370C5; clan 3: CYP350A1, CYP350C5, CYP361A1; clan 4: CYP4AN-like, CYP4AP2, CYP4AP3, CYP4C33-like1)의 서열에 대해 진화적으로 보존된 서열의 유사도를 분석하고 계통분석을 실시하였다. 또한 3종류의 서로 다른 크기의 polystyrene beads (0.05-, 0.5-, 6-㎛ PS beads; 0.1, 1, and 10 mg/L)에 48시간 노출된 기수산 물벼룩에서 이들 9종의 CYP 유전자의 발현을 real time reverse transcription polymerase chain reaction (RT-PCR)로 분석하였다. 결과적으로 기수산 물벼룩 CYP 유전자는 모두 진화적으로 보존된 motif를 가지고 있으며 계통분석 결과 각각 clan 2, 3, 4에 속하는 것으로 확인되었다. 이는 기능적으로 보존되어 있음을 의미한다. CYP 유전자 중 clan 2에 속하는 CYP370C5와 clan 3에 속하는 CYP360A1, 그리고 clan 4에서는 CYP4C122 유전자의 발현이 0.05-㎛ PS beads에 노출되었을 때 유의하게 증가하는 양상을 보였으며, 이는 이들 유전자가 PS 대사에 관여한다는 것을 의미한다. 본 연구는 미세플라스틱이 해양 무척추 동물에 미치는 생물 영향을 분자적 수준에서 이해하는데 도움이 될 것이다.

• 대한한방내과학회지
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• 제29권4호
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• pp.846-855
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• 2008

Objects : The aim of this study was to investigate the influence of five herbal medicines on cytochrome P450 3A4 drug-metabolizing enzymes in human liver microsomes. Methods : To use human liver microsomes, an extract of five herbal medicines, which are Artemisia princeps Pampan, Sophora jeponica Linne, Panax notoginseng F. H. Chen, Lithospermum Erythrorhizon Sieb., and Cirsium maackii Maxim, which together are called Jihyulyak(止血藥, drugs for arresting bleeding, hemostatics), was co-incubated and measured for relative enzyme activity in incubation condition compared to ketoconazole, a representative inhibitor of CYP 3A4. Results : We showed that all five of the traditional herbal medicines had no inhibition effect of CYP 3A4 at 10, 20, 30, 40, and $50{\mu}g/ml$ doses in human liver microsomes, although Sophora japonica Linne(SJL) showed a little inhibition at about 81% inhibition rate of control. However, this result is not enough to prove that SJL has a CYP 3A4 inhibition effect. Moreover, we can't make sure that those rates had significant induction effect on CYP 3A4. Conclusions : The result of this study could support that those herbal medicines are safer than chemical drugs, even if this is the basic step to prove that result.

• Biomolecules & Therapeutics
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• 제22권2호
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• pp.155-160
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• 2014

Thelephoric acid is an antioxidant produced by the hydrolysis of polyozellin, which is isolated from Polyozellus multiplex. In the present study, the inhibitory effects of polyozellin and thelephoric acid on 9 cytochrome P450 (CYP) family members (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) were examined in pooled human liver microsomes (HLMs) using a cocktail probe assay. Polyozellin exhibited weak inhibitory effects on the activities of all 9 CYPs examined, whereas thelephoric acid exhibited dose- and time-dependent inhibition of all 9 CYP isoforms ($IC_{50}$ values, $3.2-33.7{\mu}M$). Dixon plots of CYP inhibition indicated that thelephoric acid was a competitive inhibitor of CYP1A2 and CYP3A4. In contrast, thelephoric acid was a noncompetitive inhibitor of CYP2D6. Our findings indicate that thelephoric acid may be a novel, non-specific CYP inhibitor, suggesting that it could replace SKF-525A in inhibitory studies designed to investigate the effects of CYP enzymes on the metabolism of given compounds.

• 대한예방한의학회지
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• 제16권3호
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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.

• Archives of Pharmacal Research
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• 제27권3호
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• pp.319-323
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• 2004

Cytochrome P450 (CYP) 3A4 is of great interest because of its important roles in the oxidation of numerous drugs and xenobiotics. HDJ-1, a molecular chaperone in human, is known to assist the correct folding of unfolded proteins. To achieve a high yield of recombinant human CYP3A4 in Escherichia coli, the CYP3A4 encoding gene was co-expressed with the chaperone HDJ-1, under the control of an inducible tac promoter in a bicistronic format. The levels of expression of the CYP3A4 in the bicistronic construct reached up to 715 nmol $(liter culture)^{-1}$ within 16 h at $37^{\circ}C$, which was about a 3.3-fold increase compared to that of the CYP3A4 alone without the HDJ-1. By co-expression with HDJ-1, the catalytic activity of CYP3A4 was also increased by -15-fold. The amount of activity increase was similar to that of the CYP production at the whole cell level. The present over-expression system may be useful for the rapid production of large amounts of active CYP3A4 in E. coli.

• Toxicological Research
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• 제32권3호
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• pp.207-213
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• 2016

Although propolis is one of the most popular functional foods for human health, there have been no comprehensive studies of herb-drug interactions through cytochrome P450 (CYP) inhibition. The purpose of this study was to determine the inhibitory effects of propolis on the activities of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4 using pooled human liver microsomes (HLMs). Propolis inhibited CYP1A2, CYP2E1 and CYP2C19 with an $IC_{50}$ value of 6.9, 16.8, and $43.1{\mu}g/mL$, respectively, whereas CYP2A6, 2B6, 2C9, 2D6, and 3A4 were unaffected. Based on half-maximal inhibitory concentration shifts between microsomes incubated with and without nicotinamide adenine dinucleotide phosphate, propolis-induced CYP1A2, CYP2C19, and CYP2E1 inhibition was metabolism-independent. To evaluate the interaction potential between propolis and therapeutic drugs, the effects of propolis on metabolism of duloxetine, a serotonin-norepinephrine reuptake inhibitor, were determined in HLMs. CYP1A2 and CYP2D6 are involved in hydroxylation of duloxetine to 4-hydroxy duloxetine, the major metabolite, which was decreased following propolis addition in HLMs. These results raise the possibility of interactions between propolis and therapeutic drugs metabolized by CYP1A2.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1659-1664
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• 2012

TSAHC [4'-(p-toluenesulfonylamido)-4-hydroxychalcone] is a promising antitumorigenic chalcone compound, especially against TM4SF5 (four-transmembrane L6 family member 5)-mediated hepatocarcinoma. We evaluated the potential of TSAHC to inhibit the catalytic activities of nine cytochrome P450 isoforms and of P-glycoprotein (P-gp). The abilities of TSAHC to inhibit phenacetin O-deethylation (CYP1A2), coumarin 6-hydroxylation (CYP2A6), bupropion hydroxylation (CYP2B6), amodiaquine N-deethylation (CYP2C8), diclofenac 4-hydroxylation (CYP2C9), omeprazole 5-hydroxylation (CYP2C19), dextromethorphan O-demethylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), and midazolam 1'-hydroxylation (CYP3A) were tested using human liver microsomes. The P-gp inhibitory effect of TSAHC was assessed by [$^3H$]digoxin accumulation in the LLCPK1-MDR1 cell system. TSAHC strongly inhibited CYP2C8, CYP2C9, and CYP2C19 isoform activities with $K_i$ values of 0.81, 0.076, and $3.45{\mu}M$, respectively. It also enhanced digoxin accumulation in a dose-dependent manner in the LLCPK1-MDR1 cells. These findings indicate that TSAHC has the potential to inhibit CYP2C isoforms and P-gp activities in vitro. TSAHC might be used as a nonspecific inhibitor of CYP2C isoforms based on its negligible inhibitory effect on other P450 isoforms such as CYP1A2, CYP2A6, CYP2B6, CYP2D6, CYP2E1, and CYP3A.