• 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 Life Science
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• v.26 no.1
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• pp.42-49
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• 2016

The retinoic acid (RA) plays an important role in the growth and development of many cells, and bioactive RA concentration is regulated by several enzymes, including CYP26A1. The expression of the CYP26A1 gene is regulated by RA, and the CYP26A1 gene is one of the candidates for RA-responsive genes. Although CYP26A1 genes are cloned from several animals, cloning of the CYP26A1 gene from cows has not been reported yet. The promoter region of CYP26A1 from cows was cloned by PCR and analyzed by sequence alignment with human and mouse CYP26A1. The RA-responsive element (RARE), DR-5 (ttggg), was located in this region and was perfectly conserved. The promoter region of bovine CYP26A1, which contains DR-5, was ligated to the luciferase reporter gene on transient transfection assays. The expression of CYP26A1-Luc promoter was activated by ATRA treatment in lung-derived mtCC cells. Co-transfection with RAR-α or -β with ATRA significantly activates the expression of CYP26A1-Luc promoter; however, it was less effective with either RAR-γ or RXR-γ. In addition, the endogenous gene expressions measured by Q-RT-PCR in mtCC cells were not significantly affected by ATRA treatment for 2 days; however, the expression of the endogenous CYP26A1 gene was diminished sharply at day 3 with ATRA treatment. In conclusion, the promoter region of bovine CYP26A1 contains conserved DR-5 RARE, which functions as a binding site for RAR-α or -β, and it is involved in the regulation of CYP26A1 gene expression and the control of RA signaling in mtCC cells.

• BMB Reports
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• v.43 no.8
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• pp.530-534
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• 2010

Cytochrome P450 (CYP) 1A2 gene polymorphisms are thought to be involved in the metabolism of theophylline (TP). We aimed to investigate the effect of CYP1A2*1C, CYP1A2*1D, CYP1A2*1E, and CYP1A2*1F polymorphisms of the CYP1A2 on TP metabolism by PCR-RFLP in 100 Turkish patients with chronic obstructive pulmonary disease (COPD) receiving TP. One hundred and one healthy volunteers were included as control group. The genotype frequencies of the CYP1A2*1D and CYP1A2*1F were found to be significantly different in the patients compared to the controls. The "T" allele at -2467 delT and the "C" allele at -163 C > A in the CYP1A2 displayed association with a significantly increased risk for COPD. "T" allele at -2467 delT was also associated with a high risk of disease severity in COPD. In conclusion, our data suggest that genetic alterations in CYP1A2 may play a role both in the pharmacogenetics of TP and in the development of COPD.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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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.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.5
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• pp.407-412
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• 2001

Many drugs are primarily metabolized by the cytochrome P450s (CYPs). Drug metabolites would be important allergens for adverse drug reactions such as drug eruptions. Skin tests with a suspected drug have conducted to identify causative drugs of drug eruptions, with vehicles such as white petrolatum, DMSO, ethanol. This study will compare the expression of rat CYP isozyme mRNAs between the skin and the liver, with examining an effect of the vehicles on the cutaneous CYPs using semi-quantitative RT-PCR. Thirty-two Sprague-Dawley rats between the ages of six and eight weeks were divided as four groups. One group was used to compare the constitutive mRNA expression between skin and liver, while the others were to examine the effects of three vehicles. The ratios of expression of CYP1A2, CYP2B1/2, CYP2E1, CYP3A1, and CYP4A1 were significantly higher in the liver than the skin. However, CYP1A1 and CYP2C11 were higher in the skin than liver. The effects of vehicles were quite different; white petrolatum significantly induced CYP1A1 (p=0.012) and CYP2C11 mRNAs, while ethanol inhibited CY P1A1 and CYP2B1/2. DMSO did not make any changes. The results suggest that rat skin can participate in drug metabolism with their own CYP isozymes. The effects of vehicles on the cutaneous CYP expression should not be ignored and may be applied for determination of an appropriate vehicle for certain drug(s).

• Biomolecules & Therapeutics
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• v.22 no.2
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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.

• Toxicological Research
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• v.32 no.3
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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 Environmental Health Sciences
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• v.29 no.3
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• pp.9-15
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• 2003

The modification of CYP2El activity is a matter of considerable interest because of its role in the metabolic activation of a variety of environmental toxicants. In the present study, the time-course of changes in human CYP2El activities was determined following treatment with solvents (acetone, dimethylsulphoxide or pyridine) using intact HepG2 cells transfected by human CYP2El. Hydroxylation of chlorzoxazone was used for the measurement of CYP2El activity. CYP2E1 protein level was increased upon cultivation of cells in the presence of the solvents for 24 hr. Determination of CYP2El activities after 24 ht cultivation with the solvents demonstrated that acetone or dimethylsulphoxide increased, whereas pyridine inhibited the activities. This differential effect of the solvents on CYP2El activities persisted to subsequent 24 ht. Competitive inhibition study suggested that pyridine has stronger binding affinity to CYP2E1 than acetone or dimethylsulphoxide. These results demonstrate that different binding affinity of the solvents to CYP2El plays important role in determining real CYP2El activity in intact cells after exposure to the solvents. Present study would be helpful in precise understanding of human CYP2El-mediated toxicity.

• Genomics & Informatics
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• v.7 no.4
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.

• Natural Product Sciences
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• v.10 no.5
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• pp.197-206
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• 2004

Cytochrome P4501A2 (CYP1A2) is responsible for the metabolic activation of a number of aromatic amines and amides to mutagenic and carcinogenic moieties. Considerable variations in the level of CYP1A2 expression in humans have been reported. Thus, the level of human CYP1A2 may determine an individuals susceptibility to these chemicals. Given its importance, the molecular mechanisms of CYP1A2 regulation have been studied by many groups. Direct interactions between transcription factors with the promoters of the gene represent one of the primary means by which the expression of CYP1A2 is controlled. In this review, several important cis elements, transcription factors and the effects of deacetylation/methylation of promoter regions that play an important role in the induction by PAHs as well as constitutive expression of human CYP1A2 are discussed.