Extraction, Separation And Determination Of Ginsenosides In Panax Ginseng C.A. Meyer

Panax ginseng C. A. Meyer, which is widely used as traditional Chinese medicine,has been frequently used as medicine, healthy food and food additives. Ginsenosides which are the main bioactive components of Panax ginseng, have unique pharmacological activity. In this thesis, the extraction, separation and determination of ginsenosides were studied.1. The ginsenosides in Panax ginseng C. A. Meyer were obtained by atmospheric pressure microwave-assisted extraction and high pressure microwave-assisted extraction. The spectrophotometry was employed to determine the total contents of ginsenosides. The influences of the kind of extraction solvent, power of microwave, extraction pressure and extraction time etc. on the extraction yield were investigated. The optimal extraction conditions were found and the comparison with the traditional extraction method was carried out. HPLC-UV was employed to determine the ginsenosides in Panax ginseng, and the contents of ginsenosides which were obtained by different extraction methods were compared. To expand the application, the proposed method was applied to extraction of baicalin in Niuhuang Shangqing Pills. The results showed that microwave extraction method is effective for extracting ginsenosides with the merits of high extraction yield, short extraction time and small amount of solvent.2. Ginsenosides can be divided into two category: neutral ginsenosides and malonyl ginsenosides. Ginsenosides, especially malonyl ginsenosides, were thermally unstable and can degrade into corresponding neutral ginsenosides during thermal extraction. Neutral ginsenosides can be degraded into some rare ginsenosides which were found in the extract. So content and kind of ginsenosides in Panax ginseng extract will be influenced by extraction methods, especially malonyl ginsenosides. So to choose suitable extraction method and extraction conditions are very necessary. In this thesis the stability and the contents of ginsenosides obtained by atmospheric pressure microwave-assisted extraction and high pressure microwave-assisted extraction were studied. The malonyl ginsenoside m-Rb1, m-Rc, m-Rb2 and m-Rd were unstable, and easy to be degraded into corresponding neutral ginsenoside Rb1, Rc, Rb2 and Rd. When atmospheric pressure microwave-assisted extraction was applied, the malonyl ginsenosides did not degrade in methanol, but completely degraded in 70% (v/v) ethanol for 6h and in water for 3h. When high pressure microwave-assisted extraction was applied, the malonyl ginsenosides completely degraded at 600 kPa in methanol, 400kPa in 70% (v/v) ethanol and 300kPa in water. When water was used as extraction solvent, six neutral ginsenosides were completely degraded and partly remove glycosyls into the sub-ginsenosides at 600 kPa , such as sub-ginsenoside Rh1,Rg3,Rg2,Rk1/Rk5,Rs4/Rs5 etc. So the sub-ginsenosides can be directly obtained from the ginseng root.3. Static state floatation and dynamic floatation were used to separate and enrich ginsenosides in Panax ginseng extract. To obtain the best floatation efficiency, the factors which influenced the floatation were optimized. To expand the application of this method, icariin extracted from Epimedium was separated and enriched by floatation. The results showed that flotation was a good method for separation and enrichment of protopanaxadiol ginsenosides. Floatation method is suitable for the separation and purification of protopanaxadiol ginsenosides.4. Ginsenosides were determined by HPLC-ELSD. The effect of the pressure of carrying gas and drift tube temperature on the peak shape and peak area were studied. The optimal experimental conditions were obtained. The main ginsenosides in different parts of Panax ginseng, red ginseng, American ginseng and Sanqi were studied by HPLC-ELSD. The rare ginsenosides were studied by HPLC-ESI-MS. The contents and kinds of ginsenosides in different parts of Panax ginseng and in different species of Panax ginseng were compared.