Studies On The Preparation Of Protopanaxadiol Type Pseudo-ginsenoside By The Ginseng Protopanaxadiol Saponins

Panax ginseng C.A.Meyer,a perennial plant belonging to the Araliaceae family,is known for its drug properties that help to relieve pathologic symptoms,promote health and prevent potential diseases.Therefore,it is also called "Honeysuckle,Goblin,God grass,The king of grass",it is famous for medicinal herbs.Ginseng clinical application is very extensive,involving the inside and outside,women,children,facial features,bone injuries and other subjects,it can play a revitalized,emergency role.Therefore,ginseng is well-known for home and abroad,preferred by domestic and foreign scholars of all ages.Ginseng contains a variety of pharmacological active ingredients,its main active ingredient is ginsenoside.Some protopanaxadiol ginsenosides have a strong antitumor effect,and protopanaxadiol type Pseudo-ginsenoside which side chain was modified are also reported to have good antitumor activity.However,these protopanaxadiol type saponins are rare ginsenosides and are difficult to obtain.It is reported that the preparation of Pseudo-ginsenoside Rh₂,its raw material is rare ginsenoside Rh₂,which is costly and is not conducive to its in-depth research and development.In this paper,protopanaxadiol ginsenosides are used as raw materials,which are low cost and easy to obtain.The acetylation method was used to protect the hydroxyl groups,the acid catalyzed conversion method was used to modify the side chain,the alkali degradation and other methods were used to de-glycosyl.And purified by the positive and negative phase separation of the column chromatography.Finally,correspond rare side-chain altered ginsenoside derivatives were obtained.Based on the analysis of the physical and chemical properties,IR,1H-NMR,13C-NMR,HMQC,HMBC,1D-ROESY and HR-ESI-MS.Six compounds were identified:?E???Z?-Pseudo-ginsenoside Rg₃ {12?,25-dihydroxydammar-?E?-20?22?-ene-3-O-?-D-glucopyranosyl-?1?2?-?-D-glucopyranoside and 12?,25-dihydroxydammar-?Z?-20?22?-ene-3-O-?-D-glucopyranosyl-?1?2?-?-D-glucopyranoside};?E???Z?-Pseudoginsenoside Rh₂ {?-D-Glucopyranoside,?3?,12?,20E?-12,25-dihydroxydammar-20?22?-ene-3-yl and ?-D-Glucopyranoside,?3?,12?,20Z?-12,25-dihydroxydammar-20?22?-ene-3-yl};?E???Z?-Pseudo PPD{Dammar-?E?-20?22?-ene-3?,12?,25-triol and Da mmar-?Z?-20?22?-ene-3?,12?,25-triol}.In the step of alkali degradation,the degradation temperature,the alkali concentration and the degradation time were explored and studied by single factor and orthogonal test.Finally,the optimum degradation conditions were explored.Pseudo-ginsenoside Rh₂: at 230?,NaOH concentration is 12%,reaction 40 min,the maximum degradation rate is 18.0%.Pseudo PPD: at 250 ?,NaOH concentration is15%,reaction 50 min,the maximum degradation rate is 18.2%.In this paper,the method of obtaining rare protopanaxadiol type Pseudo ginsenosides by using two-step directly based on degradation of the ginseng panaxadiol saponins was proposed for the first time.This method suitable for production.The raw materials is easy to take,the reaction is simple.This method is not only for ginsenoside derivatives provide a good basis and reference,but also for the new saponins research and development provide a better direction in the future research.