Preparation Of Panaxadiol Aglycone By The Methods Of Biotransformation And Inorganic Catalysis

In this paper,the preparation of protopanaxadiol(PPD)by the methods of biotransformation and inorganic catalyst was studied,respectively.Finally,the separation and purification of products was also studied.In the experiment of enzymatic preparation of PPD,the enzyme from Absidia sp.G48r strain could hydrolyze 20(R)-Rg3 after cultured for 9d using 3.5%of Panax ginseng C.A.Meyer extraction as inducer,but could hydrolyze 20(S)-Rg3 after cultured for 6d using 1.5%of Panax ginseng C.A.Meyer extraction as inducer.The optimal fermentation conditions for biotransformation of 20(R)-Rg3 was at 50 ?,pH 4.0,after reacted for 60h,and at the substrate concentration of 1.0mg/ml.The optimal fermentation condition for biotransfor-mation of 20(S)-Rg3 was at 50?,pH 5.0,after reacted for 24h,and at the substrate concentration of 2.0mg/ml.Under optimal reaction condition,1.0g of Rg3(R:S=14:86)was used for enzymatic reactions.After reaction,the product was firstly extracted using n-butanol and it gave 0.772g crude product with a yield of 77.2%.Then,the n-butanol-extract product was further extracted using petroleum ether and it gave 0.117 g of purified product with a yield of 11.7%.After two-step organic extraction,the content of protopanaxadiol in the final product was increased from 80.06%to 86.94%.In the inorganic catalyst method,the effect of the substrate concentration,concentration of Fe3+,the temperature and time on the reaction was studied,respectively.The best condition conversion of ginsenoside C-K by Fe3+ was at the substrate concentration of 3.0mg/ml,Fe3+concentration of 1.8mol/L,50?,and for 30h.After reaction,the product was firstly extracted using ethyl acetate and it gave 0.825g crude product with a yield of 55.0%.Then,the ethyl acetate-extract product was further extracted using petroleum ether and it gave 0.131 g of purified product with a yield of 8.7%.After two-step organic extraction,the content of protopanaxadiol in the final product was increased from 71.34%to 84.45%.