| Panax ginseng C.A.Meyer,which is used as traditional Chinese medicine in long history,is a kind of perennial Araliaceae Panax Linn herbals. It's said that ginseng widely used can invigorate five viscera,stabilize the spirite and nerve,dispel pathogen,protect eyelight,avail intelligence and keep body healthy and longevity in《Shennong Bencao scripture》. Ginsenoside is one type of glycoside compounds ,belonging to triterpenoid, which is formed of glucide and aglucone. Ginsenosides are divided into three types):(one is oleanane pentacyclic triterpenoid saponin ,whose sapogenin is oleanolic acid type. The others are dammarane tetracyclic triterpenoid saponins, whose sapogenins are protopanaxadiol type (PPD), protopanaxatriol type (PPT). In addition, some side-ring and skeleton changed type is the fouth sapogenins.A plenty of research demonstrate that ginsenosides are the pharmacologically active constituents of Panax ginseng. Ginseng has a broad range of beneficial effects including meliorating pathology conditions of cardiovascular system,nerve system and immune system,depressing the growth of tumors and so on. There are many studies showing that the intestinal bacterial metabolites exhibited excellent pharmacological activities . Up to now,it's not successful to achieve complete synthesis of ginsenosides,and it need to distill ginsenosides from all parts of ginseng to meet the medical needs. For some lower levels and stronger activity of saponin, it's still difficult to be a new drug development.Therefore,through reconstruct of some activity ginsenosides,it can't only find some much stronger activity compounds,but also improve characters of compounds and enhance bioavailability of compounds. It is necessary and meaningful to produce the novel type ginsenosides for the main pharmacological activities of ginseng.In the paper ,on the basis of the chemical constituents, degradation methods and metabolism of ginsinosides, our investigation emphases that prepare dammar-(E)- 20(22)- ene-3β,12β,25-triol named the novel ginsenoside by our study team from panaxadiol . The acid degradation products were isolated using the chromatography and recrystallizaton. The compounds were elucidated by chemical evidence and the extensive application of 1H, 13CNMR and DEPT NMR techniques.The total ginsenosides from the root of Panax ginseng were hydrolyzed to prepare panaxadiol for 8 h at 80°C in a solution of 50% EtOH, which contained 10% HCl. Two compounds have been isolated from the acid hydrolysate . The process of isolation was as follows: The acid hydrolysate was subjected to silica gel chromatography and eluted with mixtures of petroleum ester and ethyl acetate (5:3) to afford two fractions . The fractions was further subjected to repeat recrystallization by MeOH and H2O to,respectively,and obtain two compounds:oleanolic acid and 20(R)-panaxadiol.The panaxadiol was hydrolyzed to prepare dammar - (E) -20(22) -ene- 3β,12β,25 -triol for 4.5 h at 80°C in a solution of 75% EtOH, which contained 15% HCl. Four compounds have been isolated from the acid hydrolysate . The process of isolation was as follows: The acid hydrolysate was subjected to silica gel chromatography and eluted with mixtures of chloroform-methanol-ethyl acetate-water (2:2:4:1, lower layer): chloroform (2:1) to afford four fractions . The fractions was further subjected to repeat recrystallization by MeOH and H2O , respectively , and obtain four compounds:20(R)- propanaxdiol,dammar- (E)-20(22)-ene- 3β,12β,25-triol,dammarane-26-ethyl-3β,12β,20(R),25-tetrol,and.dammarane-3β,12β,20(R),25-tetrol.In this thesis, we used HCl ethanol solution separately to degradate panaxadiol, and the target compound was dammar-(E)-20(22)-ene-3β,12β,25-triol named novel panaxadiol. Through single factor test ,we chosed acid concentration, degradation time and degradation temperature three factors for degradation process researching. The results showed that the optimal conditions for degradation was 85°C, 10% hydrochloric acid degradation 4 h.
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