Chinese Medicine Schisandra Composition Of The Pharmacokinetics And Metabolism Studies

Traditional Chinese medicine(TCM) is a great treasure of medical system originated and practiced in China.Through thousand of years' clinical evaluation,TCM has been verified efficacious and unique in diseases treatment and health care.Along with the knowledge change of medical therapy and arising call for "Back to Nature",the unique therapeutic theory and pharmacologic effect of TCM has attracted global attention and acceptance which stimulate the extensive research of TCM.It has been known that China, the origin of TCM,has long application history and abundance resource of TCM that gives us incomparable advantage in related research field.To our embarrassment, however,China has been left behind in TCM research field by Japan,South Korea,USA, Europe and so on.In order to realize " TCM Modernization Strategy",TCM research program has been supported and accelerated to meet the standards of international market in China.TCM pharmacokinetic(PK) study which draws on kinetic theory and analytical method to describe quantificationally interaction and transformation of TCM components plays an important role in the course of TCM modernization.The above results would make valuable sense to clarify the foundation of effective components and pharmacological mechanism of TCM,design and optimize dosage regimen,facilitate TCM new drug development and quality control.Schisandra chinensis.(Wuweizi) is a classical tonic that exhibits hepatoprotection confirmed by clinical evaluation.Pharmacological research about Schisandra chinensis. has a expanded advancement,while its pharmacokinetic development is limited just as other TCM previously.On the basis of previous studies,several parts of pilot pharmacokinetic studies were undertaken to investigate PK characteristics of Schisandra chinensis.,accelerating its proper clinical application,meanwhile exploring research mode of TCM pharmacokinetics:1.To establish a simple,specific and rapid biological analysis method of four active lignans from Schisandra chinensis.,profiling PK feature of the four components in normal and pathological model;2.To investigate the correlation between pharmacokinetics(PK) and pharmacodynamics(PD) of multi-components from Schisandra chinensis.3.To characterize and compare the chemical,liver microsomal incubation,PK and PD fingerprints which would be compared and analyzed;4.To study the interaction between constitutes from Schisandra chinensis and drug metabolism enzymes/drug resistance protein P-gp using liver microsomes incubation,PCR,Westernblot,Caco-2 cell transwell methods;5.To investigate PK interaction of components from Schisandra chinensis with other coadministration drugs in vivo.The results were shown as follows:1.PK and PD research of four lignans from Schisandra chinensis in vivo.1.1 The HPLC/MS analysis method for the simultaneous quantification of schisandrin, schisantherin A,deoxyshisandrin andγ-schisandrin in biological samples showed good sensitivity,linearity of response,and high precision and appropriate for PK study of the four lignans from Schisandra chinensis.1.2 After a single oral dose of alcohol extraction of Schisandra chinensis to rats,the plasma concentrations of schisandrin,schisantherin A,deoxyshisandrin andγ-schisandrin were all relatively high at 0.25h which suggested a quick absorption of four compounds.The T_max and MRT values of four analytes were about 7h and 10h, while schisandrin had the highest AUC,andγ-schisandrin was the poorest.1.3 After a single oral dose of alcohol extraction of Schisandra chinensis to rats intoxicated with CCl₄ which induced a significant acute liver injury(ALI),the plasma concentrations of schisandrin,schisantherin A,deoxyshisandrin andγ-schisandrin were much higher than that of untreated rats.The C_max,AUC,T_max and MRT were all increased or prolonged significantly while parameter CLz/F was reduced obviously.The results demonstrated that the changes on above PK parameters may due to the enhancement of absorption and decreases enzyme-dependent metabolism or elimination of four components.Furthermore,the PK change of four lignans in ALl rats was mainly explained by the reduced CYP450 isoenzymes' activity involved in metabolism of the four components.1.4 The PK profiles of schisandrin,schisantherin A,deoxyshisandrin andγ-schisandrin were relatively related to the time-course of ALT level in ALI rats,which showed the correlation between PK and PD of components from Schisandra chinensis to certain extent.2.Fingerprint study of Schisandra chinensis extraction2.1 The chemical,microsomal incubation,PK and PD fingerprints were established using HPLC-UV-MS method.The components in water extraction of Schisandra chinensis. were relatively less and stable in liver microsomal incubation compared with alcohol extraction.The components in chemical fingerprint of alcohol extraction could be found in related PK and PD fingerprints that suggested the foundation of effective components from Schisandra chinensis,and provided senseful information for its following researches including absorption in gastrointestinal tract and effect differences between single constitute and extraction or complex prescription.Several metabolites of components from Schisandra chinensis,were detected in PK and PD fingerprints that contained information of its effective mechanism and metabolism.2.2 Schisandrin,schisantherin A,deoxyshisandrin andγ-schisandrin could be found in chemical,microsomal incubation,PK and PD fingerprints,that indicated the entrance of four lignans into plasma and may be used as "PK Marker" for "systematic exposure" investigation of alcohol extraction or other pharmaceutics from Schisandra chinensis.Likewise,two metabolites of the four lignans,7, 8-dihydroxy-schizandrin and another one whose molecular weight was 432,emerged in liver microsomal incubation,PK and PD fingerprints could be recognized as "DM Marker" of alcohol extraction or other pharmaceutics from Schisandra chinensis.3.Effect of components from Schisandra chinensis,on hepatic drug metabolizing enzymes/drug efflux transporter P-gp.3.1 Multiple administrations of alcohol extraction of Schisandra chinensis.(1.5g/Kg,qd×7d) can induce the activities of CYP2E1/3A,mRNA and protein expression of CYP2B/3A and CYP2E1/3A while inhibite the activities of CYP2C/2D to some extent.In addition,the alcohol extraction(28-120μg/mL) showed inhibition on the activitie of CYP450 isoenzymes in vitro.3.2 Multiple administrations of water extraction of Schisandra chinensis.(1.5g/Kg,qd×7d) induced the activity of CYP2E1,mRNA and protein expression of CYP2C/3A and CYP2E1/3A while inhibited the activity and mRNA expression of CYP2D to some extent.Moreover,the water extraction(100-500μg/mL) also showed inhibition on the activity of CYP450 isoenzymes in vitro.3.3 According the result of transfer experiments performed in Caco-2 transwell model, deoxyshisandrin was the possible substrate of P-gp among the four lignans. Alcohol/water extraction and the four lignans from Schisandra chinensis,showed different extent inhibition on P-gp,while alcohol/water extraction,deoxyshisandrin andγ-schisandrin were more intensive than schisandrin or schisantherin A. 4.PK interaction of components from Schisandra chinensis,and clinical drugs4.1 After multiple administration of alcohol extraction of Schisandra chinensis.,the PK profiles of four lignans,schisandrin,schisantherin A,deoxyshisandrin andγ-schisandrin,exhibited the reduced AUC and shorter MRT.As a result,it could be concluded that multiple dosing of alcohol extraction from Schisandra chinensis. could accelerate the metabolism of four lignans themselves possibly by induction of CYP450 isoenzymes as indicated in Part 3.1.4.2 It is reported that CYP2D is involved in the hepatic metabolism of anti-depression agent sertraline.The PK interaction between sertraline and alcohol extraction of Schisandra chinensis,was investigated just because of the inhibition on CYP2D after single or multiple doses of alcohol extraction.The results showed the less inhibition on the sertraline metabolism,which was not consisitant with the inhibition study.The difference between them might be due to the involvement of multiple enzymes in the biotransformation of sertraline.However,it is still necessary to pay attention to possible interaction when components from Schisandra chinensis,were coadministrated with drugs metabolized by CYP2D in clinical.4.3 Chlorzoxazone,a centrally acting muscle relaxant,was mainly metabolized by CYP2E1 in vivo.Because of the significant inhibition and induction on CYP2E1 after single or multiple doses of alcohol extraction of Schisandra chinensis,the PK interaction of chlorzoxazone and alcohol extraction coadministration was studied in vivo.The result demonstrated that single dose of alcohol extraction had no obvious effect on chlorzoxazone PK profile,while multiple dosage could induce the metabolism of chlorzoxazone by changing Tmax,Cmax,AUC and MRT.The result suggested that multiple doses of alcohol extraction could accelerate chlorzoxazone metabolism through induction of CYP2E1 activity and protein expression.As a result,when components from Schisandra chinensis were coadministrated for a long time with drugs metabolized by CYP2E1,the drug dosage should be increased properly to avoid drug efficacy failure.4.4 Tacrolimus,a new type of immunosuppressive drug,was mostly metabolized by hepatic CYP3A isoenzyme.Because of its narrow therapeutic window and unexpected toxic effect,blood drug concentration should be monitored in clinical application.The liver transplant patients usually take tacrolimus with the preparation of Schisandra chinensis. Under the above condition,the CYP4503A mediated interaction between them may happen in all probability,which would result in organ rejection or adverse effect. Our result showed that the blood concentration of tacrolimus was elevated significantly(T_max increased by 10 folds,AUC increased by 7-12 folds) by single or multiple dosing of alcohol extraction of Schisandra chinensis,which magnified the possibility of adverse effect.As a result,the dosage oftacrolimus should be reduced to avoid the occurring of adverse effect when this drug was used in combination with components from Schisandra chinensis.It is reported that most common used oral drugs were metabolized by CYP3A in human and most of them were also cosubstrates of both CYP3A and P-gp.Thus,coadministration interaction should be concerned between those drugs,especially the drugs with narrow therapeutic window like tacrolimus,and pharmaceutics from Schisandra chinensis. Comprehensive analysis should be given to personalize drug therapy.In conclusion,relatively systematic metabolism and pharmacokinetics was performed on Schisandra chinensis,in the present study in order to provide reliable experimental data for its clinical application.Meanwhile,the research work also proposed the methods and inspiration for TCM PK exploring research in its modernization course.