• Journal of Society of Preventive Korean Medicine
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• v.12 no.2
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• pp.37-49
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• 2008

In this study, we experimented the influence of three herbal medicines, which are Saussurea lappa Clarke, Poncirus trifoliata Rafin, Citrus aurantium Linne, which are called 'Yigiyak(理氣藥)' on drug metabolizing enzyme cytochrome P450 3A4 in Human Liver Microsome. Above all, the reason for this study is that herbal medicines can be assumed that herbs might have interactions with drugs, other herbs, alcohol and chemicals whether those are much better synergy effects than expected effects when the medicine was treated alone or not. As a result, we showed that all of five traditional herbal medicines had no CYP 3A4 inhibition effect on 10, 20, 30, 40, $50{\mu}g/m{\ell}$ doses in Human Liver Microsome even Saussurea lappa Clarke showed a little inhibition as about 93% and 79% inhibition rate of control. However, this result are mostly not enough to prove that SLC has a CYP 3A4 inhibition effect. Moreover, it is not that those rates showed that those herbal medicines have CYP 3A4 induction effect. In conclusion, the result could support that those herbal medicines are more safe than chemical drugs even if this is the basic step to prove that result. Therefore, more specific studies to support this result, which are Kinetic study, cell and animal study then finally until clinical research, are required.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.127-133
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• 1994

• Journal of Society of Preventive Korean Medicine
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• v.12 no.3
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• pp.99-113
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• 2008

In this study, the author experimented the influence of five herbal medicines, which are Lonicera japonica Thunb, Paeonia suffruticosa Andr., Fraxinus rhynchophylla Hance, Gardenia jasminoides Ellis, Scutellaria baicalensis George which are called 'Chungyulyak(淸熱藥)' on drug metabolizing enzyme cytochrome P450 3A4 in Human Liver Microsome. Above all, the reason for this study is that herbal medicines can be assumed that herbs might have interactions with drugs, other herbs, alcohol and chemicals whether those are much better synergy effects than expected effects when the medicine was treated alone or not. As a result, we showed that all of five traditional herbal medicines had no CYP 3A4 inhibition effect on 10, 20, 30, 40, $50{\mu}g/m{\ell}$ doses in Human Liver Microsome. However, this result are mostly not enough to prove that PMT has a CYP 3A4 inhibition effect. Moreover, it is not that those rates showed that those herbal medicines have CYP 3A4 induction effect. In conclusion, the result could support that those herbal medicines are more safe than chemical drugs even if this is the basic step to prove that result. Therefore, more specific studies to support this result, which are Kinetic study, cell and animal study then finally until clinical research, are required.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.240.1-240.1
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• 2001

• YAKHAK HOEJI
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• v.59 no.5
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• pp.201-206
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• 2015

The aim of the present study was to optimize in vitro method for the prediction of drug-induced liver injury using human liver microsomes (HLM). Cytotoxicity test of cyclophosphamide and acetaminophen in HepG2 cells cultured with HLM showed that the newly established condition using 0.375 mg/ml HLM for 24 hr incubation was comparable or more sensitive than the previously established condition using 0.75 mg/ml HLM for 12 hr incubation. Although the cytotoxic effect of troglitazone was completely attenuated by 0.75 mg/ml HLM, it was augmented by 0.375 mg/ml HLM in the presence of the NADPH-generating system. The cytotoxic effect of chlormezanone, a withdrawn drug due to hepatotoxicity in human, was increased by HLM in the presence of the NADPH-generating system. In contrast, the cytotoxic effect of methapyrilene, a withdrawn drug due to hepatotoxicity in rats, was decreased by HLM in the presence of the NADPH-generating system. The present study suggests that the optimized in vitro method using HLM can be useful for the prediction of drug-induced hepatotoxicity.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.297-306
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• 2005

It is known that dehydroepiandrosterone (DHEA) shows a dual effect, prooxidant or antioxidant, depending on the do-sage or physiological status of animals. The purpose of this study was to determine the effects of DHEA administration at low dose on lipid peroxidation, protein carbonylation and fatty acid composition in liver. Sprague Dawley male rats were fed either com oil diet containing $15\%$ com oil or fish oil diet containing $2\%$ corn oil + $13\%$ sardine oil, with or without $0.2\%$ DHEA for 9 weeks. Atherogenic index and hepatic triglyceride and cholesterol levels were significantly reduced by DHEA administration in rats fed with fish oil diet. Hepatic lipid peroxide product (TBARS) and protein carbonyl levels were significantly higher in rats fed with fish oil diet than in rats fed with corn oil diet. However, DHEA administration significantly reduced the hepatic thiobarbituric acid-reactive substance (TBARS) and conjugated diene levels in rats fed with fish oil diet. Contents of C16 : 0, C16 : 1, C20 : 5 and C22 : 6 in hepatic microsome were higher in rats fed with fish oil diet than in rats fed with corn oil diet, and contents of C18 : 2 and C20 : 4 were lower than in rats fed with com oil diet. DHEA administration significantly increased C16 : 0 and C18 : 3 contents and reduced C18 : 2 content in rats fed with com oil diet, while it increased C16 : 0 and C18 : 1 and reduced C20 : 5 and C22 : 6 in rats fed with fish oil diet. On overall, DHEA administration increased saturated fatty acid (SFA) and reduced polyunsaturated fatty acid (PUFA) in hepatic microsome, thereby PUFA/SFA ratio was significantly (p < 0.0001) reduced without the change of n-3/n-6 ratio. Taken together, low dose of DHEA administration lowered PUFA/SFA ratio in hepatic microsomal membranes and also showed antioxidative effect especially in fish oil-induced highly oxidative stress condition through blocking increases of C20 : 5 and C22 : 6 contents.

• YAKHAK HOEJI
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• v.43 no.6
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• pp.834-842
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• 1999

The metabolism and pharmacokinetics of M-l, which is metabolite of pentoxifylline, have been studied in human liver microsomes. Biphasic kinetics was observed from the Eadie-Hofstee plot for the formation of both metabolites of M-l. For the kinetics of pentoxifylline, mean values of $V_{max1}{\;}and{\;}V_{max2}$ were 1,648 and 5,622 nmol/min/mg protein, and the estimated values of $K_{ml}{\;}and{\;}K_{m2}$ were 0.180 and 4.829 mM, respectively. For M-3, mean values of $V_{max1}{\;}and{\;}V_{max2}$ were 0.062 and 0.491 nmol/min/mg protein, and estimated values of $K_{ml}{\;}and{\;}K_{m2}$ were 0.025 and 1.216 mM. The formations of pentoxifylline and M-3 from M-1 were indentified by using several selective inhibitors of cytochrome P450 isoformes at 0.05-5 mM concentration of M-1 in human liver microsomes. For the analysis of low (0.05 mM) concentration of M-1, where the affinity was expected as low, indicated that CYPlA2 and CYP3A4 were major P450 isoforms responsible for pentoxifylline and M-3 formation. CYP3A4 and CYP2A6 appeared to be P450 isoforms responsible for M-3 formation at high (5 mM) concentration of M-1.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.2
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• pp.65-74
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• 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.

• The Journal of Korean Medicine
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• v.24 no.2
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• pp.40-46
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• 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.

• Toxicological Research
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• v.12 no.2
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• pp.155-161
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• 1996

The enzymatic properties for NADPH-P450 reductase domain of a fusion protein between human cytochrome P450 1A1 and rat NADPH-P450 reductase expressed in Escherichia coli were investigated. The fusion plasmid pCW/1A1OR-expressed E. coli membrane showed high NADPH-cytochrome c reductase activity ($830.1\pm 85.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$), while pCW control vector and P 450 1A1 expression vector pCW/1A1 showed relatively quite low activity ($4.35\pm 0.49, 3.27\pm 0.50 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively). The kinetic curves for NADPH-cytochrome c reductase followed typical Michaelis-Menten kinetics. The $K_{max}$ and $V_{max}$ for NADPH-dependent reductase activity were $8.24\pm 2.61\mu $and $817.9\pm 60.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively, whereas those for cytochrome c-dependent reductase activity were $19.97\pm 2.86\mu M$ and $1303.5\pm 67.1 nmol\cdot min^{-1}\cdot mg protein^{-1}$. The reductase activities were also compared with those of rat, porcine and human liver microsomes. The activity of pCW/ 1A1OR-expressed E. coli membrane was 15.2-fold higher than that of rat liver microsome. Treatment with benzo(a)pyrene, 7-ethoxyresorufin and $\alpha$-naphthofiavone which are known as specific substrates or inhibitor for human P450 1A1 increased NADPH-cytochrome c reductase activity of fusion protein in E. coli membrane dose-dependently. These results demonstrate that the membrane topology of fused enzyme may be important for activity of its NADPH-P450 reductase domain.