Separation Of Ginsenoside Rh2 Group From Biotransformation

Ginsenoside F2 and Rh2 group are rare ginsenosides with high activity and high absorption rate.In this paper,high levels of ginseng protopanaxadiol type ginsenoside(PPD),including Rb1,Rb2,Rc,Rd,et al,were used as the substrate to prepare ginsenoside F2 by biotransformation.We can provide a basis for industrial production.First,determine optimum conditions for the enzymatic reaction of preparing ginsenoside F2,including substrate type,substrate concentration,reaction time,temperature,pH.Ultimately the optimum conditions was defined as follows:sp.848 strains optimal substrate was PPD,the optimum substrate concentration was 6%,the optimum enzyme reaction time was 36 hours,the optimum temperature was 40 ?,the optimum pH was 5.0;sp.48 strains optimal substrate was PPD,the optimum substrate concentration was 6%,the optimal enzyme reaction time was 24 hours,the optimum temperature was 40?,the optimum pH of 5.0.In such conditions,above 80%PPD was transformated to F2.According to the above results,ginsenoside F2 was prepared in large quantities by biotransformation:96 g PPD was used as the substrate to react with the enzyme of sp.848 strain and sp.48 strain respectively.Then respectively obtain 76.2 g and 77.5 g products.After the reaction,the enzyme was recovered by centrifugation,with recovery of 60%.Then mix the recovered enzyme of the two strains,react with PPD substrate under optimal conditions.After the reaction,recover the enzyme and react again.Then obtain 104.0 g products in total.35 g enzymatic reaction product was separated by silica gel column chromatography,eluted by elution phase with the composition of V(chloroform):V(methanol)=9.0:1.0,and V(chloroform):V(methanol)=8.6:1.4 in order.18.2 g ginsenoside F2 monomer was obtained through concentrating eluention of F2 single point under reduced pressure,with a yield of 52.0%,and the purity was 96.7%by HPLC detection.lOg ginsenoside F2 was further used for preparing ginsenoside Rh2 group by particular enzyme reagent from our laboratory.Extract saponin with water-saturated n-butanol three times,combin the n-butanol,wash out sugar and other impurity with by water for three times,distill under reduced pressure.6.1 g products of ginsenoside Rh2 was obtained with a yield of 90.0%by HPLC detection.The content proportion of four isomers 20(S)-Rh2,20(R)-Rh2,Rk2 and Rh3 was 32.3:31.2:12.0:21.5.