{"title":"Inhibitory effects of schisandrin A and schisandrin B on CYP3A activity.","authors":"W L Li, H W Xin, M W Su, L Xiong","doi":"10.1358/mf.2010.32.3.1434161","DOIUrl":null,"url":null,"abstract":"Our aim was to investigate the inhibitory effects of schisandrin A and schisandrin B on cytochrome P450 (CYP3A) activity in rat liver microsomes and the mechanism of this interaction. 1'-Hydroxy midazolam and midazolam 1-hydroxylation catalyzed by CYP3A were analyzed by high performance liquid chromatography (HPLC). Results showed that schisandrin A and schisandrin B inhibited CYP3A activity with IC(50) values of 6.60 and 5.51 microM and K(i) values of 5.83 and 4.24 microM, respectively. A dilution assay plot of each inhibitor gave a slope value of up to 91% that of the control samples. The inactivation of CYP3A activity by schisandrin A and schisandrin B was found to be both time-and concentration-dependent (schisandrin A: K(I) = 4.51 microM, K(inact) = 0.134/min; schisandrin B: K(I) = 3.01 microM, K(inact) = 0.112/min). We conclude that the inhibition of CYP3A activity in rat liver microsomes by schisandrin A and schisandrin B is mostly attributed to a mixed noncompetitive and complete inhibition.","PeriodicalId":18443,"journal":{"name":"Methods and findings in experimental and clinical pharmacology","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2010-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1358/mf.2010.32.3.1434161","citationCount":"22","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Methods and findings in experimental and clinical pharmacology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1358/mf.2010.32.3.1434161","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 22
Abstract
Our aim was to investigate the inhibitory effects of schisandrin A and schisandrin B on cytochrome P450 (CYP3A) activity in rat liver microsomes and the mechanism of this interaction. 1'-Hydroxy midazolam and midazolam 1-hydroxylation catalyzed by CYP3A were analyzed by high performance liquid chromatography (HPLC). Results showed that schisandrin A and schisandrin B inhibited CYP3A activity with IC(50) values of 6.60 and 5.51 microM and K(i) values of 5.83 and 4.24 microM, respectively. A dilution assay plot of each inhibitor gave a slope value of up to 91% that of the control samples. The inactivation of CYP3A activity by schisandrin A and schisandrin B was found to be both time-and concentration-dependent (schisandrin A: K(I) = 4.51 microM, K(inact) = 0.134/min; schisandrin B: K(I) = 3.01 microM, K(inact) = 0.112/min). We conclude that the inhibition of CYP3A activity in rat liver microsomes by schisandrin A and schisandrin B is mostly attributed to a mixed noncompetitive and complete inhibition.