ABSTRACT
Objective::To evaluate the effects of Valeriana amurensis roots and rhizomes extract and its active constituents on the activities of six major cytochrome P450 (CYP450) enzymes in human liver microsomes. Method::Coumarin, bupropion, tolbutamide, omeprazole, dextromethorphan and testosterone were used as probe substrates for CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and CYP3A4, respectively. Taking their specific metabolites of hydroxylation or demethylation (7-hydroxycoumarin, hydroxybupropion, 4-hydroxytolbutamide, 5-hydroxyomeprazole, dextromethorphan, 6β-hydroxytestosterone) as indicators of enzyme activities. The analytical indexes were used to establish an in vitro model of human liver microsomes of Cocktail probe substrates. This method was applied to evaluate the effects of V. amurensis roots and rhizomes extract and its active constituents on human liver microsomal enzymes. Result::The V. amurensis roots and rhizomes extract had different inhibitory effects on CYP2B6, CYP2C9, CYP2D6 and CYP3A4, their half-inhibitory concentration (IC50) values were 87.49, 1.73, 68.29, 2.80 mg·L-1, respectively. Among the 9 lignans, (-)-massoniresinol-3α-O-β-D-glucopyranoside had a moderate inhibitory effect on CYP2A6 with an IC50 value of 8.51 μmol·L-1, 8, 8′-dihydroxypinoresinol-4, 4′-di-O-β-D-glucopyranoside had a moderate inhibitory effect on CYP2D6 with an IC50 value of 8.73 μmol·L-1, (+)-medioresinol-4, 4′-O-di-β-D-glucopyranoside had a moderate inhibitory effect on CYP2B6 and CYP2C9 with IC50 values of 5.41 μmol·L-1 and 8.20 μmol·L-1. Conclusion::The V. amurensis roots and rhizomes extract and its active constituents have inhibitory effects on liver CYP450 enzymes. Therefore, in the clinical study of new drugs, it is necessary to fully evaluate the risk of drug interactions caused by combination therapy.
ABSTRACT
Objective:To study on the effect of Inula cappa extract on the activities of six cytochrome P450(CYP450) enzymes in rats by Cocktail probe method. Method:Rats in the I. cappa high and low dose groups were given oral administration of active fractions of I. cappa at a dose of 8.127,2.709 g·kg-1·d-1 of the material for 7,14 d,repectively.Probe drugs(caffeine,midazolam,tolbutamide,omeprazole,metoprolol,chlorzoxazone) were simultaneously injected to rats after administration.Plasma was collected at different time after the administration of probe drugs.The plasma concentrations of these six probes were measured by UPLC-MS and their corresponding pharmacokinetic parameters were calculated with DAS 2.0. Result:Compared with the control group,only the apparent volume of distribution(V) of midazolam was increased;area under the curve(AUC0-t and AUC0-∞)and half-life period(T1/2) of caffeine,midazolam,tolbutamide and omeprazole were increased and the clearance rate(CL) of them was decreased in rats of I. cappa groups.But there were no differences in pharmacokinetic parameters of chlorzoxazone and metoprolol. Conclusion:I. cappa can reduce the enzymatic activities of CYP3A,CYP1A2,CYP2C9 and CYP2C19 in rats at different degree,among which CYP3A is the strongest.
ABSTRACT
Aim To develop a sensitive,rapid and ac-curate LC-MS /MS method for the simultaneous deter-mination of cytochrome P450 probe substrates,inclu-ding caffeine and its metabolite paraxanthine for CYP1 A2,omeprazole and its metabolite 5-hydroxyome-prazole for CYP2C1 9,dextromethorphan and its metab-olite dextrorphan for CYP2D6,midazolam and its me-tabolite 1 ′-hydroxymidazolam for CYP3A4.Methods Probe drugs with the IS diazepam were extracted using ethyl acetate.Gradient elution was performed on an Agilent Eclipse Plus-C1 8 column (50 mm ×2.1 mm, 3.5 μm).The mobile phase consisted of 0.01 % for-mic acid(1 mmol·L -1 ammonium formate)and aceto-nitrile.The flow rate was 0.3 mL·min -1 ,and the in-jection volume was 1 0 μL.The analyte was detected u-sing electrospray ionization(ESI)in positive multiple reaction monitoring(MRM+)mode.The reaction se-lected ions were 1 95.0 /1 38.1 m /z for caffeine, 1 81 .1 /1 24.1 m /z for paraxanthine,346.1 /1 98.1 m /z for omeprazole,362.1 /21 4.1 m /z for 5-hydroxyome-prazole, 272.2 /1 47.1 m /z for dextromethorphan, 258.1 /1 57.1 m /z for dextrorphan,326.1 /291 .1 m /z for midazolam,342.1 /324.1 m /z for 1 ′-hydroxymid-azolam and 285.1 /1 54.0 m /z for diazepam as internal standard.Results The linear ranges of caffeine,pa-raxanthine,omeprazole,5-hydroxyomeprazole,dextro-methorphan, dextrophan, midazolam and 1 ′-hydroxymidazolam were 1 .95 ~2 000,0.98 ~250, 0.48 ~2 000,0.98 ~250,0.98 ~2 000,0.48 ~1 25,1 .95 ~2 000 and 1 .95 ~250 μg·L -1 respec-tively.The RSD of all probe drugs was less than 1 5%and matrix effects in plasma on the ionization of probe drugs were negligible.Conclusion This sensitive and rapid LC-MS /MS method is suitable for determination of the drug/metabolite concentrations in plasma,so as to study the metabolism of CYP1 A2, CYP2C1 9, CYP2D6 and CYP3A4 in depth.
ABSTRACT
This study was designed to explore the impact of depression on kidney-yang deficiency in rats. Rats were repeatedly injected with hydrocortisone for 21 days to establish the depression model with kidneyyang deficiency. Tolbutamide, chlorzoxazone, theophylline, midazolam, omeprazole and dextromethorphan were used as substrates of CYP2C6, CYP2E1, CYP1A2, CYP3A2, CYP2D1, and CYP2D2 to test the depression impact on drug metabolism. Plasma concentrations of six CYP450 were determined by LC-MS/MS and used as pharmacokinetic parameters. Consequently, metabolism of theophylline, chlorzoxazone and tolbutamide were accelerated significantly in the model relative to the control (P<0.01), but dextromethorphan, omeprazole and midazolam did not exhibit a significant difference. The present study suggests that depression with kidneyyang deficiency had a strong induction of CYP2E1 and moderate induction of CYP1A2, CYP2C6 in the rat model.
ABSTRACT
Objective DryLab software was used to assist high performance liquid chromatography (HPLC) method to test and isolate six Cytochrome P450 (CYP450) probe substrates.Methods Six CYP450 probe substrates were selected and the right HPLC method was developed and validated with the assistance of DryLab software.Results The new HPLC method with the assistance of DryLab software could test and isolate six probe substrates with degrees of isolation more than 2.00. The correlation coefficients (R> 0.999 8) indicated high linear correlation between the concentrations and the peak areas among six probe substrates. Recovery studies showed good results for all the probe substrat from 86.38% to 110.29%. And therelative standard deviation (RSD) ranged from 1.69% to 3.80% with its intra-day and inter-day precision ranging from 0.42% to 2.01%, and 1.36% to 2.29%, respectively.Conclusions The developed HPLC method with the assistance of DryLab could test and isolate six probe substrates with shortertime than the HPLC method alone.
ABSTRACT
OBJECTIVE: To study the effect of capsaicin on the activities of CYP1A2, 2C11 and 3A in rats by cocktail probe drug method. METHODS: Male rats were randomly divided into six groups. Three groups of rats (group A, B and C) were orally given capsaicin 25 mg · kg-1 once daily for 1, 3, 7 d, respectively. The other three groups (group a, b and c) received orally 0.5% carboxymethylcellulose sodium (CMC-Na) once daily for 1, 3, 7 d, respectively, as the blank control groups. Plasma was collected at different time after drug administration. The concentrations of caffeine, tolbutamide and dapsone in plasma were determined by HPLC method. The plasma concentration-time data was analyzed with DAS2.1.1 software to obtain the pharmacokinetic parameters of the cocktail probe drugs. RESULTS: Compared with the blank control group, the AUC0-t AUC0-t and pmax of caffeine in group C significantly decreased, along with significant increase of CL/F. The AUC0-t and pmax of tolbutamide in group C both significantly decreased compared with the blank control group. Meanwhile, the AUC0-t and AUC0-t of dapsone in group C significantly decreased, along with significant increase of CL/F and V/F. CONCLUSION: Capsaicin may significantly induce the activities of CYP1A2, CYP2C11 and CYP3A in rats after consecutive administration for 7 d. Reduced therapeutic efficacy of the drugs metabolized by CYP1A2, CYP2C11 and CYP3A should be anticipated during long-term administration of capsaicin.