The Research On Bioconversion And Pharmacokinetics Of Aucubin From The Seeds Of Eucommia Ulmoides Oliv

Aucubin,a typical compound of iridoid glucoside,is isolated from the seeds of Eucommia ulmoides Oliv.,had shown abundant activities such as high liver-protective activity,antiviral activity,anti-inflammatory activity.In addition,aucubin also showed promoting collegen sythesis,Immunomodulatory,antileukemic,antispasmodic and photoprotective activities.Some research found that the biological activity of aucubigenin was much higher than that of aucubin.To study the bioconversion of aucubin into aucubigenin,we investigate the content and activity ofβ-glucosidase extracted from nine Chinese medicinal materials. The protein content andβ-glucosidase activity of crude extracts were determined by Coomassie Brilliant Blue's method and 3,5-Dinitrosalicylic acid(DNS)'s method, respectively.The efficiency of hydrolyzing aucubin was tested by the crudeβ-glucosidase from Chinese medicial materials.Theβ-glucosidase from Semen Armeniacae Amarum has the highest efficiency of hydrolyzing aucubin and enzyme activity,whose specific activity was 174.21 U·mg^-1.The relations between protein content and the value of enzyme activity showed weak correlation.However,a strong correlation was observed between the value of enzyme activity and the efficiency of enzymatic hydrolysis.Therefore,we have chosenβ-glucosidase from Semen Armeniacae Amarum to hydrolyze aucubin,which was also called emulsin.The isolation of aucubigenin was described through enzymatic hydrolysis of aucubin with emulsin at 37℃for 60 min followed by a procedure of extraction with ethlyl acetate at low temperature.The yield of conversion of aucubin into its aglycone was 31.41%.The purity of aucubigenin was reached to 93.23%.Aucubigenin was identified through the methods of UV,IR,¹HNMR,¹³CNMR,and MS spectrum. To study the pharmacokinetics of aucubin in rabbit,the high performance liquid chromatography was applied to detect the concentration of aucubin in rabbit plasma. For the experimental group,the drug concentration-time data were also fitted to a two-compartment model with first order absorption after a dose of 500 mg·kg^-1oral administration and 100 mg·kg^-1intravenous injection of aucubin.This method could determine the aucubin level in plasma and are suitable for its pharmacological study.