Extraction And Purification Of Taxol In Taxus Media Branches

The extraction and primary purification of taxol from the branches of Taxus media was studied systematically in this paper.In the basis of founding the suitable methods about qualitative and quantitative analysis, different extracted and purification methods were researched.Finally,the integrated preparation technology about taxol was founded.First of all,the methods of TLC qualitative analysis and HPLC quantitative analysis were founded in this paper.The expanding solvent of TLC was chloroform/ethyl acetate/methanol(88:7:5,v/v/v),the ribbon was well dispersed and the value of R_f was 0.48.The chromatogram condition of HPLC was as follows:C18column,acetonitrile/water(53:47,v/v) as mobile phase,flow rate was 0.8mL/min,column temperature was 28℃, UV detector at 228nm.Secondly,the elementary extract of taxol from the branches of Taxus media was studied.With the methods of solvent extraction,ultrasonic assistant extraction and supercritical liquid extraction,the technics conditions of each method were researched.The optimal conditions of solvent extraction were as follows:with ethyl acetate/acetone(1:1,v/v) as extracting solvent,the time of extraction was 7h and the temperature 45℃,the volume of solvent 14multiple(14mL solvent per gram material), the granularity of raw material less than 0.250mm,third class extraction. Following this condition,after the primary chloroform/water dispensatory extraction,the content of taxol reached 1.07%in crude extracts,with the recovery 97.76%.The optimal conditions of ultrasonic assistant extraction were as follows:the time of extraction was 1.5h and the temperature 40℃,the volume of solvent 12multiple,the power of ultrasonic 70W.Following this condition,after primary chloroform/water dispensatory extraction,the content of taxol reached 0.86%in crude extracts,with the recovery 98.59%.And then,supercritical CO₂ fluid extraction technology was used to extract taxol.With the preconditions of separation temperature 30℃,pressure 6.5MPa and CO₂ flux 25 L/h,the best process conditions were extraction pressure 30MPa,temperature 47℃,time 3.5h(static time 0.5h),the entrainerφ(CH₃CH₂OH)=85%. Following this optimal conditions,after the primary chloroform/water dispensatory extraction,validatory tests were carried out with the average recovery oftaxol 90.70%,the content reached 0.86%in crude extracts.At last,the extraction mechanics of each method were discussed in this paper, and then built up corresponding theoretical models and validated them by experiment.Thirdly,the purification technics of crude extracts was discussed in this paper.The crude extracts were purified with the methods of solidliquid extraction,liquid-liquid dispensatory extraction,silica gel column chromatogram,TLC(preparation scale),deposition and crystal.Finally, the flaxen taxol crystal was received with the purity of taxol 73.16%.It is proved that the taxol was well purified.