Study On The Extraction And Purification Process Of Total Platycosides From Radix Platycodonis

Radix Platycodonis, the roots of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae) has long been used as a traditional folk remedy for respiratory diseases. Its triterpenoid saponins, namely, platycosides, have been proved to be the most effective components of Radix Platycodonis. Many reports have been found out about the extracting and purifying process of total platycosides, while the extraction rate and content of total platycosides were not high enough to match the national standard for new Chinese Traditional Medicines of the fifth category. The present study is undertaken to set up an industrial-practical preparing process of total platycosides with which we can develop the intermediate into a phlegm-dispelling and cough-relieving new drug.During the course of our study, a reasonable extracting and purifying process was established by a combination of single-factor experiments and orthogonal designs, using the yield and content of total platycosides as the evaluation markers. The quality control of the intermediate was also investigated and a colorimetric analysis was employed to determinate the content of total platycosides. The optimum process was obtained as follows: The plant materials were extracted with water under reflux for three times, respectively with 8 times more than the weight of the plant materials for 90 minutes, then with 6 times for 60 minutes, and finally with 6 times for 30 minutes. After centrifuging and concentrating to 0.5 g/mL, the extract was subjected at a loading rate of 3BV/h to an AB-8 macroporous resin column with a diameter-length ratio of 1:5. After an absorption period of 30 minutes, the column was eluted with 5BV water and then with 4BV 70% EtOH both at a flow rate of 4BV/h. The 70% EtOH eluate was dried under vacuum to provide the intermediate.10 intermediates prepared with this optimum process were investigated, in which the content of total platycosides and Platycodin D were not less than 52% and 4.5%, respectively.