Extraction And Chemical Transformation Of Ginsenosides

Objective:A bionic extraction method of ginsenoside from ginseng at ambient temperature was developed firstly.The content of eight ginsenosides?Rg₁,Rd,Rf,Re,Ro,Rc,Rb₁,Rb₂?in the extract,which were determined using an HPLC-QqQ/MS in MRM mode,were used to evaluate the bionic method.The extraction condition was optimized including extraction time,ratio and type.Another ultrasonic method was established at the same time for comparison.The transformation pathway of PPT and PPD type ginsenosides was further studied based on HPLC-ESI-MSⁿ.Finally,the extracted total ginsenosides using bionic method were transformed chemically to qualitatively analyze the transformation products rapidly.Methods:For the bionic extraction method,pepsin and pancreatin were employed to simulate the in vitro gastrointestinal environment and to prepare the extraction solution.The impact of the extraction ratio,time and temperature on the extracted content of ginsenoside were further evaluated.For the ultrasonic extraction method,the ginsenosides were extracted in methanol solution.The extraction time,ratio,and concentration of solution were optimized.The content of ginsenoside was quantitatively analyzed based on an established HPLC-QqQ/MS method in the MRM mode.And the methodology of the bionic method was validated for its repeatability,precision and stability.In the chemical transformation experiment of ginsenoside,phosphotungstic acid was used as the catalyst.The PPD-type Rd and Rg₃,PPT-type R₁ and the extracted total ginsenosides were transformed.The structure of the products was identified using HPLC-ESI-MSⁿ.Results:In the same extraction time,the developed bionic extraction method showed more content of the eight ginsenosides than those of ultrasonic method and exhibited more extraction efficiency.In the aqueous acid solution,ginsenoside Rd had 10 different conversion products,which were 20?S?-and 20?R?-25-OH-Rg₃,25-OH-Rk₁ and 25-OH-Rg₅,20?S?-Rg₃ and 20?R?-Rg₃,?20S,25?-epoxy-Rg₃ and?20R,25?-epoxy-Rg₃,Rk₁ and Rg₅,ginsenoside Rg₃ is the same as Rd;PPT type ginsenoside R₁ has 9 kinds of products,20?S?-25-OH-R₂,20?R?-25-OH-R₂,25-OH-T₅,20?S?-R₂,20?R?-R₂,20?S?-25-epoxy-R₂,20?R?-25-epoxy-R₂,T₅,?20E?-3?,12?-dihydroxy-6?-?2-O-?-D-xylopyranosyl-?-d-glucopyran osyloxy?Methane-20?22?,24-diene;After biomimetic extraction,the total saponins were converted into 12 products,respectively 20?S?-Rf₃?20?R?-Rf₃?20?S?-Rf₂?20?R?-Rf₂?20?S?-Rg₂?20?R?-Rg₂?20?S?-25-OH-Rg₃?20?R?-25-OH-Rg₃?20?S?-Rg₃?20?R?-Rg₃?Rk₁ and Rg₅.Conclusion:In comparison with ultrasonic extraction method,the artificial gastric juice derived bionic extraction method showed better extraction efficiency.In combination with the quantitative analysis of HPLC-MS,the developed bionic extraction method exhibited good repeatability,precision and accuracy.It provides an alternative method for the ambient extraction and analysis of ginsenoside.Furthermore,the ginsenosides extracted by the bionic method could be chemically transformed into rare ginsenosides,the structure of which were conveniently identified using HPLC-ESI-MSⁿ.The results above establish the foundations for the extraction,analysis,transformation and preparation of ginsenosides.