Study On Separation And Preparation Of High Purity Sennoside A

Sennoside A is one of the main effective components of traditional Chinese medicine senna,which has many biological activities such as purgative,hemostatic,antibacterial,anticancer and so on.It is widely used in the treatment of digestive system diseases.The preparation of high purity Sennoside A can not only provide reference materials for its analysis and detection,but also provide the corresponding material basis for the clinical development and research of Senna.In this paper,the extraction,separation and purification of Sennoside A were studied.With the content of Sennoside A as the index,the adsorption properties of five different types of macroporous adsorption resins were studied from two aspects of static adsorption rate and static desorption rate.The results showed that the exchange adsorption capacity of X-5 resin for Sennoside A was the strongest.The effects of various factors on the purification of Sennoside A by X-5 resin were investigated by single factor experiment,and the optimal experimental parameters were determined.HPLC analysis showed that the content of Sennoside A was increased to 21.45%by X-5 resin.Sennoside A was further purified by column chromatography.The effects of various factors on the purification of Sennoside A by column chromatography were investigated with purity and recovery as indexes.The optimal experimental parameters were determined as follows:the adsorbent was silica gel,the eluent was chloroform-methanol with gradient elution,the sample type was not alkalized,the ratio of diameter to height is 1:9,the loading mass was 0.3 g,and the elution flow rate was 2.0 mL/min.Under these conditions,the purity of Sennoside A reached 68.33%.It was concluded that one of the main impurities in crude product II was aloe emodin diglucoside.In order to obtain higher purity of Sennoside A product,the purification process of preparative high performance liquid chromatography was studied.The optimal experimental parameters were determined as follows:the mobile phase was acetonitrile-1%glacial acetic acid gradient elution,the detection wavelength was 340 nm,the flow rate was 18 mL/min,and the sample volume was 2.0 mL.Under these conditions,the purity of Sennoside A was increased to 99.42%.The qualitative analysis of Sennoside A was carried out by IR,NMR and LC-MS.The short-term stability of Sennoside A was studied.