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Study on the Induction of Commonly Used Traditional Chinese Patent Medicines on the P450 3A4 and P-glycoprotein

Author: JiangBo
Tutor: ChenWanSheng
School: Second Military Medical University
Course: Pharmacognosy
Keywords: Induction traditional Chinese patent medicine Drug-drug interaction CYP3A Shexiang Baoxin Pill P-gp
CLC: R285
Type: Master's thesis
Year: 2010
Downloads: 355
Quote: 1
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Abstract

The herbs were always used for long periods of time, many CYP450 metabolic enzymes and transporters activity can be induced. This kind of induction can lead to clinical drug-drug interactions. In order to prevent this interaction, the study on induction of the traditional Chinese medicines on liver metabolic enzymes CYP3A4 and the major drug transporters will help us to avoid the drug-drug interaction.In our study, the HepG2 cells were incubated with test drug for 48 h in vitro. The activity of CYP3A was measured by the quantification of 1-hydroxymidazolam formation using a liquid chromatographic-tandem mass spectrometry method. Meanwhile, the levels of mRNA of CYP3A were determined by real-time PCR. We used the positive inducter to evaluate our model. Then, the inductive effects of about thirty three Chinese traditional patent medicines on CYP3A were evaluated respectively in HepG2 cells. The result indicated that the Shexiang baoxin pill (SBP) can induce the CYP3A4 enzyme activity strongly.To further verify the reliability of the model, in vitro in HepG2 cells and in vivo in rats approaches were used to estimate the inductive effect of SBP on CYP3A. SBP increased mRNA expression and enzyme activity of CYP3A in a dose-dependent manner in HepG2 cells. As well as the microsomal activity and the expression of CYP3A in rats were both up-regulated in the SBP pretreated rats. Furthermore, we took advantage of the HepG2 cells to further identify its ten main components (muscone, testosterone, ginsenoside Rf, ginsenoside Rgl, ginsenoside Re, borneol, bufalin, cinobufagin, resibufogenin, cinnamaldehyde) as a potential inducer of CYP3A. The real-time PCR results showed that enzyme activity of CYP3A in HepG2 cells treated with bufalin (0.01μg/mL), cinobufagin (0.03μg/mL) increased 1.58-fold and 1.14-fold respectively. Muscone at higher concentration (10μg/mL) increased the enzyme activity and mRNA expression. Thus, bufalin, cinobufagin, resibufogenin might play the key role in the enzyme-inducing effect of SBP. In conclusion, there may be potential drug-drug interactions during long-term clinical application of the drug which contain the bufalin, cinobufagin, resibufogenin, when substrates of CYP3A4 are co-administered.In this study, Caco-2 cell monolayers were treated with SBP (30,20, 10μg/mL) for 72 h to investigate the relationship between the potential affects of SBP on P-gp. After SBP treatment, the ratio of the apparent permeability coefficients (Papp) of rhodamine-123 (a substrate of P-gp) efflux is similar to the control, but an increase in mRNA expression of MDR1 (P-gp) was confirmed by real-time PCR. Furthermore, we investigate the effects of SBP on gene expression on message levels of mdr1a and mdr1b in small intestine of the rats treated orally with SBP (6.75mg/kg) for 6 days. The results of real-time PCR showed that the levels of mdr1a and mdr1b were increased 1.54 and 2.88-fold respectively.In summary, we established a model for screening the inducer. We used the positive inducter to evaluate our model. Meanwhile, the inductive effects of Chinese traditional patent medicines were evaluated by the models. The deepgoing study of drug-drug interaction will help us to choose right drug and adjust drug dose to avoid drug side effect and attain more drug efficacy.

Study on the Induction of Commonly Used Traditional Chinese Patent Medicines on the P450 3A4 and P-glycoprotein

Abstract

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