The Catalytic Conversion Of Trialcohol Ginsenoside Into Rh1

This paper aimed at panaxtriol type ginsenosides catalytic conversion ginsenosides Rh1.Rg1 was prepared using a triol saponin Re as a substrate in large quantities by enzymatic conversion.About catalytic Rg1 ginsenosides of metal ions,First,the metal ions were screened,and then select the substrate solvent system,and the reaction conditions of different substrate solvent system is optimized.Finally,the reaction process of Fe³⁺catalyzing ginsenoside Rg1 was studied under ethanol-water system.First,the optimal fermentation conditions forα-rhamnosidase were initially determined as follows:the inducer was sophora japonica,the content of the best inducer was 20%,and the fermentation time was 6d.The optimal reaction conditions for the hydrolysis of triol ginsenoside Re byα-rhamnosidase is:10%ethanol concentration,1.3%substrate concentration,12h reaction time,40%reaction temperature and 5.0 buffer pH.Secondly,studying the catalytic reaction of 32 different metal ions,the results show that FeCl₃ is the best.Then we selected the best substrate solvent as ethanol-water system.The optimum reaction conditions of the best system were preliminarily determined.Thirdly,by Fe³⁺of ethanol-water system through the research of catalytic reaction process of ginsenosides Fe³⁺direct catalytic cracking of ginseng saponin Rg1 on C-20glucoside keys,in the generated 20（S,R）-Rh1,Rk3 and Rh4 dehydration reaction generated at the same time,and then when the amount of 20（S,R）-Rh1 accumulated to a certain extent,by hydration addition reaction generated 20（S,R）-25-OH-Rh1.Finally,14 g of ginsenoside Rg1 was used as substrate,and the crude product was prepared by catalytic reaction in a 50%glycol-water system.The yield was 71.4%,of which the content of 20（S,R）-Rh1 was 64.9%and 20（S,R）-Rh1,Rk3 and Rh4,and20（S,R）-25-OH-Rh1 is 71:25:4.