Separation, Purification and Biotransformation of Ginsenosides from Ginseng Bud
|School||Beijing University of Chemical Technology|
|Course||Microbial and Biochemical Pharmacy|
|Keywords||Ginseng bud Ginsenosides active carbon Prep-HPLC biotransformation|
Panax ginseng C.A. Meyer (Araliaceae), which was first recorded in Shen Nong’s Herbal Classic, is one of the famous and precious Chinese traditional herb medicines. As the main ingredient of Panax ginseng, ginsenosides has been used as a satisfactory drug for the treatment of tumor, fatigue, cardiovascular diseases, stroke and so on. G-Re, a kind of the most common ginsenside, has the particular effect on anti-diabetic and central nervous system diseases. Ginseng bud, the reproductive organ of Panax ginseng, is considered as "universal immune health products". The content of G-Re in Ginseng bud is five times higher than that in ginseng, which is the root of Panax ginseng. In recent years, lots of modern methods have been developed to separate and purify ginsenosides from ginseng, American ginseng and Sanqi root, such as ultrasound-assisted extraction, microwave-assisted extraction, ultrahigh pressure extraction, CO2 supercritical fluid extraction, macro porous resin, Prep-HPLC and HSCCC. However, few researches have been done on separating and purifying active ingredients from ginseng bud. In order to improve the bioavailability of ginseng bud, it is necessary to obtain reasonably large quantities of highly purified compounds from ginseng bud.A high concentration of overall ginsenosides and polysaccharides was dectected by Salkowski reaction and foam experiments in ginseng bud. A high effective and stability method for analysising the ginsenosides in ginseng bud was estabilished. An effctive method of extracting both the ginsenosides and polysaccharides in ginseng bud was estabilished. The purity and of ginsenosides and polysaccharides can reach to 90% and 92%.Protopanaxtriol saponins and protopanaxdiol saponins have been separated by normal-phase low pressure liquid chromatography. The silica gel thin layer chromatography was used to choose the mobile phase of normal-phase low pressure liquid chromatography was chosen. When using n-butanol-ethyl acetate-water (4:1:5, v:v:v) as the mobile phase, the two kinds of ginsenosides can be separated effectively. The optimalizing loading amount and flow-rate was less than 400mg and 10ml/min, the degree of separation and the recovery was 81.9% and 81.3% at this condition.Active carbon was used as a new media in pre-purification G-Re before Prep-HPLC purification, even in purification of other kinds of natural products. The method of separation and purification of G-Re by selective adsorption of active carbon and Prep-HPLC from ginseng bud has many advantages, such as easy, efficient, economical, environmentally friendly and susceptible to amplification and so on. Acetonitrile in water (23:77, V:V) was chosen as the mobile phase when considering the preparation of large amounts of samples. When the flow rate and loading was 6 mL/min and 20 mg, the G-Re content of the purified product, which has been pre-purified by active carbon and purified by Prep-HPLC, is 98.5%.β-D-glucuronidase enzyme (Penicillium purpurogenum) was used to transformation the ginsenosides from ginseng bud. The enzyme can convert ginsenoside Rb1 and Rd into Rg3. When the temperature is 45℃, pH value is 5.0, the concentration of the emzye is 2 mg/mL and react for 12 h, The transformation ratio was 4.95%.