• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
• /
• pp.209.1-209.1
• /
• 2003

We have previously shown that 2, 3', 4, 5' -tetramethoxystilbene(TMS) from synthetic trans-stilbene analogues, is one of the most potently selective inhibitor of recombinant human cytochrome P450 1B1 in vitro. In the present studies. the effects of TMS on the expression of cytochrome P450 1B1 were investigated in human cancer cell lines such as MCF-7 and HL -60. TCDD-stimulated P450 1B1 protein and mRNA expression was significantly suppressed by TMS in a dose-dependent manner. (omitted)

• Archives of Pharmacal Research
• /
• 제21권1호
• /
• pp.35-40
• /
• 1998

Human cytochrome P450 4F2 shows high regioselectivity in hydroxylation of stearic acid and leukotriene $ B_4.$ As a first step of its regulation study, human cytochrome P450 4F2 genomic DNA was isolated from liver of a person who was administered clofibrate for 10 years. From Southern hybridization, restriction enzyme digestion and sequencing experiments, isolated genomic DNA fragment was found to contain around 32 Kb DNA and more than 20 Kb of $5^I$ end regulatory region. Sequences of the structural gene region revealed exon 1 and exon 2. Further regulation studies would elucidate the feedback mechanisms of the oxidative degradation of fatty acids, inflammatory response and the clearance of leukotriene B4 in the liver. Furthermore, regulation study of this gene could explain the species difference in responses to peroxisome proliferator and help in the safety evaluation of peroxisome proliferating chemicals to human being.

• Toxicological Research
• /
• 제30권1호
• /
• pp.33-38
• /
• 2014

The human cytochrome P450 2J2 catalyzes an epoxygenase reaction to oxidize various fatty acids including arachidonic acid. In this study, three recombinant enzyme constructs of P450 2J2 were heterologously expressed in Escherichia coli and their P450 proteins were successfully purified using a $Ni^{2+}$-NTA affinity column. Deletion of 34 amino acid residues in N-terminus of P450 2J2 enzyme (2J2-D) produced the soluble enzyme located in the cytosolic fraction. The enzymatic analysis of this truncated protein indicated the typical spectral characteristics and functional properties of P450 2J2 enzyme. P450 2J2-D enzymes from soluble fraction catalyzed the oxidation reaction of terfenadine to the hydroxylated product. However, P450 2J2-D enzymes from membrane fraction did not support the P450 oxidation reaction although it displayed the characteristic CO-binding spectrum of P450. Our finding of these features in the N-terminal modified P450 2J2 enzyme could help understand the biological functions and the metabolic roles of P450 2J2 enzyme and make the crystallographic analysis of the P450 2J2 structure feasible for future studies.

• 한국해양바이오학회지
• /
• 제1권2호
• /
• pp.71-75
• /
• 2006

별불가사리 단백추출물을 조제하여 유방암 유발억제효과를 측정한 결과, 별불가사리 단백추출물은 estrogen-의존성의 유방암세포(MCF-7)와 estrogen-비의존성 유방암세포(MDA-MB-231)의 증식을 농도의존적으로 억제하는 효과가 있었으며, 유방암발생 발암물질 활성에 관여하는 cytochrome P450 1A1 활성도 저해하였다. 또한 유방암발생의 촉진단계에 주요한 기능을 가진 ODC 활성도 억제하였으므로 별불가사리 단백추출물은 유방암 발생을 저해할 것으로 기대된다.

• Food Science and Biotechnology
• /
• 제14권2호
• /
• pp.297-300
• /
• 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.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2003년도 춘계학술대회 논문집
• /
• pp.77-77
• /
• 2003

We have previously shown that 2, 3' , 4, 5' -tetramethoxystilbene(TMS), a trans-stilbene analogue, is one of the most potently selective inhibitor of recombinant human cytochrome P450 1B1 in vitro. In the present studies, the effects of TMS on the expression of cytochrome P450 1B1 were investigated in human mammary cell lines such as MCF-7 and MCF-10A. (omitted)

• 대한한의학회지
• /
• 제24권2호
• /
• pp.40-46
• /
• 2003

Objectives : Achyranthes bidentata radix (Usul) has been used as anti-arthritic, antiallergic, antidiuretic, and so on. Recently extracts of Achyranthes bidentata radix have shown anti-inflammatory and cancer preventive effects in vitro and in vivo. Methods : We therefore evaluated the inhibitory potential of ethanol extracts of Achyranthes bidentata radix on cytochrome P450 (CYP) isoforms-catalyzed reactions, which relate to causes of cancer and inflammation, including CYP1A2, CYP2C9, CYP2C19, CYP2E1, CYP2D6, CYP2C8, and CYP3A4, using human liver microsomal preparations. Results : The extracts showed weak or negligible inhibitory effects on CYP2C9-catalyzed (S)-warfarin 7-hydroxylation, CYP2C19-catalyzed S-mephenytoin 4-hydroxylation, and CYP2D6-catalyzed dextromethorphan O-demethylation with each IC50 over 1750 g/ml, respectively. However, it showed relatively significant inhibitory effect on CYP1A2-catalyzed phenacetin O-deethylation and CYP2E1-catalyzed chlorzoxazone 6-hydroxylation with IC50s of 970.5 g/ml and 821.4 g/ml, respectively. Conclusions : These results suggest that extracts of Achyranthes bidentata radix have inhibitory effects on CYP-catalyzed reactions, especiallyCYP1A2 and CYP2E1, in human liver microsomes. These effects appear to relate to anti-inflammatory and cancer prevention following decrease of reactive oxygen species formed by CYP, especially CYP1A2 and CYP2E1, by Achyranthes bidentata radix. However, further evaluation is necessary to demonstrate and to confirm its effects in human.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-1
• /
• pp.88-88
• /
• 2003

The syntheses of different types of stilbenoid libraries have been studied recently. In these courses, the screening of the generated natural product-mimic focused libraries led to the identification of the novel lead compounds for human cytochrome P450 (CYP) lAs, melanin production, and sortase A. A library of trans-stilbene derivatives was prepared through a new efficient solution pahse synthetic pathway and their inhibitory activities were evaluated on human cytochrome P450s(CYP) 1A1, 1A2, and 1B1 to find a potent and selective CYP1 inhibitor. (omitted)

• 대한예방한의학회지
• /
• 제7권2호
• /
• pp.65-74
• /
• 2003

Objective : The aim of present study is to evaluate the inhibitory potential of licorice extract and glycyrrhizin on cytochrome P450(CYP) in human liver microsomes. Methods : Using human liver microsomes, water extract of licorice and glycyrrhizin as an inhibitor were co-incubated with each probe drug representing selective CYP isoform activity. We measured relative metabolic activity in incubation condition compared to that with no extract of licorice using HPLC system. Results : Both water extracts of licorice and glycyrrhizin showed inhibitory effect on CYP-catalyzed reactions. CYP2C19 $(IC_{50}=126.7{\mu}g/ml)$ is most potently inhibited by water extract than other tested CYP isoforms$(IC_{50}>450{\mu}g/ml)$, but glycyrrhizin exhibited potent inhibition on CYP1A2$(IC_{50}=106.9{\mu}g/ml)$ followed by CYP2C9 and CYP2D6. Conclusion: These results indicate that water extract of licorice and glycyrrhizin have inhibitory potential on CYP-catalyzed reaction in human liver microsomes. But the mechanism of inhibition was slightly different between them Water extract of licorice mainly inhibited CYP2C19, and glycyrrhizin primarily inhibited CYP1A2. The inhibition by water extract of licorice and glycyrrhizin on CYP isoforms may cause drug interaction with co-administered drug leading to toxicity or treatment failure.

• Biomolecules & Therapeutics
• /
• 제3권4호
• /
• pp.245-250
• /
• 1995

The carbon tetrachloride($CCl_4$) has been demonstrated to have a hepatotoxic effect in human or many other species. To investigate the enzyme induction of mixed function oxygenases in liver of male Sprague-Dawley rats a single 0.1, 0.5 mι/kg dose of carbon tetrachloride were given. At 24 hr after a single dose of 0.1 mι CC1$_4$/kg weight, methanol extract of Hedera rhombea leaves was administered with 100, 500 mg/kg weight. Assays of 7-ethoxyresorufin-Ο-deethylation(EROD),7-benzyloxyresorufin-Ο-deathylation(BROD),4-nitro-phenol-UDP-glucuronosyltransferase(UDPGT), Western blot and RNA slot blot were used as representatives of the activities of cytochrome P-450 enzymes. The change of the activity of CYP1A1 form measured by EROD assay and Western analysis using 1-7-1 monoclonal antibody was not observed. The activity CYP2B1 form by BROD assay and using 2-66-3 monoclonal antibody was remarkably increased. Elevated level of CYP2B1 mRNA was shown by slot hybridization with 2B1-specific probe. Administration of methanol extract of Hedera rhombea leaves reversed the enzyme activity and the level of mRNA, which suggest the chemoprotective effect of methanol extracts of Hedera rhombea leaves to carbon tetrachloride hepatotoxlcity.