Research On The Effect Of Several Compositions From Traditional Chinese Medicine On Hepatic Microsomal Enzyme Activities

With the broad application of Traditional Chinese Medicines(TCMs),the safety of TCMs gains intensive attention recently.Wuweizi is the dried fruit of Schisandra chinensis(Turcz.)or Schisandra sphenanthera Rehd.et Wils.which belongs to Magnoliaceae family and Schisandra genus.Schisandra has the functions of anti-inflammation,anti-oxidation.immune-modulation and liver protection et al.Maidong is the tuber of Ophiopogon japonicus(Linn,f.)Ker-Gawl which is a kind of evergreen renascent herd.It has the functions of nourishing yin,moisturizing skin and improving cardiac muscle.As the widely used TCMs,to study the effects of Wuweizi and Maidong on liver drug metabolism enzymes are very important.The results can provide clues to extend the application and to ensure their safe applications.Inhibition of cytochromeP450(CYP450)by the components of Wuweizi was reported frequently.But seldom can we found the report of the major components in Wuweizi inhibiting UDP-glucuronosyltransferases(UGTs).Our previous studies showed that isoforms of Wuweizi inhibited liver drug metabolism enzymes differentially.In this study,we studied the inhibition effects of components in Wuweizi and Maidong on UGT,CYP3A4 and CYP3A5 in vitro by employing recombinant enzymes.Liver protection effects of Wuweizi lignans were also evaluated and the interactions between the lignans and the liver drug metabolism enzymes were also investigated.An isoform of Clausenamide,an active TCM component was also studied in view of its metabolism difference amid different species.In this study,the results revealed that schizandrin,schisantherin,ophiopogon saponin D(OD),ophiopogon saponin D(OD ')and ruscogenin(RU)showed obvious inhibition on UGTs.More narrowly,schizandrin and schisantherin showed significant inhibition on UGTlA3,and the IC50 value was calculated to be 10.8±0.4?M and 12.5±0.5?M.OD showed significant inhibition on UGT1A6 and UGT1A8,and the IC50 value was calculated to be 11.4±0.4?M and 40.5±0.3?M.OD' showed significant inhibition on UGT1A6 and UGT1A10,the IC50 value was calculated to be 8.7±0.7?M and 30.1 ±0.4?M.RU showed significant inhibition on UGT1A4,and the IC50 value was calculated to be 1.4±0.5?M.In addition,schisantherin showed strong inhibition towards CYP3A4 and CYP3A5.The inhibition that schisantherin towards CYP3A4 was slightly stronger than that of CYP3A5 when midazolam and nifedipine were used as the probes.However,when testosterone was used as substrate,the inhibitory effect on CYP3A4 was weaker than that of CYP3A5.By contrast,The inhibitory effect of GG on CYP3A5 was stronger than that of CYP3A4.These findings showed that the inhibitory effect of schisonesters on CYP3A4 and CYP3A5 were almost the same,while the inhibitory effect of GG on CYP3A5 was stronger than that of CYP3A4.Meanwhile,according to the study about the correlation between the liver protection and inoxidizability,Schisandra lignin extract(SLE)showed obvious reversal effect on the inhibitory liver injury.SLE played an important role in the activity of antioxidant enzymes by improving the activity of SOD and GPX in mouse liver,and the expression level of mRNAResults of the study focusing on the metabolic difference of the Clausenamide(CLA)in eight species are showed as follows:the characteristic metabolite of CLA 4-OH-(+)CLA was only found in the liver microsome of rats and guinea pig.But another characteristic metabolite 7-OH-(-)CLA was only found in the liver microsome of rats and monkeys.No obvious metabolite was found in the liver microsome of human and other species.According to the study of chemical inhibition,CYP3A was the key isoenzymes involved in the hydroxylation reaction of CLA's isomer in the rats' liver microsome.Our study showed that the plasma concentration should be monitored when patients were treated with Wuweizi or Maidong combined with the drugs metabolized by CYP3A4/5 and UGTs.SLE had a protective effect on stress liver injury.The correlation between anti-stress and liver protection may be related to hepatic microsomal enzyme activities.The results of Clausenamide isoforms metabolism difference amid different species provided clues to understand the different effects of different chemical isoforms on liver drug metabolism enzymes.