| Ginsenoside is the main medicinal ingredient of Araliaceae ginseng species,such as Panax quiquefolium L.,Panax ginseng C.A.Mey,Panax notoginseng(Burk.)F.H.Chen.The ginsenosides can be divided into common and rare types.Among them,common types are ginsenosides with high content in ginseng plants,and rare types refer to ginsenosides that are low in or absent in ginseng plants.Pharmacological studies showed that compared with common ginsenosides,rare types have more prominent anti-tumor,anti-fatigue,antioxidant and other biological activities.Therefore,in-depth research on the new preparation method of rare ginsenosides is not only of great academic significance,but also an improtant role in promoting the discovery of new medical uses of rare ginsenosides.It is the current research focus on the chemical composition of ginseng plants.In this study,three commonginsenosides,ginsenoside Re,Rb1,and Rg1,were used as research objects,which provided a scientific basis for the rapid and efficient conversion of common ginsenosides into rare types.Subcritical water and single factor experiments were used to optimize the process for converting common ginsenosides into rare ginsenosides.The process of converting common ginsenosides into rare ginsenosides provides technical support for the rapid preparation of rare ginsenosides.The first chapter summarizes the research progress of ginsenosides,especially the preparation methods and pharmacological effects of rare ginsenosides;introduces the basic properties and applications of subcritical water;briefly describes the advantages and applications of HPLC-ESI-Q-TOF-MS technology.The second chapter uses ginsenoside Re as the material and uses subcritical water for conversion.The extraction time,extraction temperature,and the ratio of ginsenoside Re to glycine are selected as influenced factors through single factor experiments.Design-Expert 8.0.6.1 software was used to design the test and fit the test data to optimize conversion of ginsenoside Rh4.The optimal process conditions were of temperature 156℃ for 13 min,and the ratio of ginsenoside Re to glycine was0.49.Peak area under liquid phase detection is 201 ± 5 m V*min.The optimal conversion process of ginsenoside Rk3 is temperature 156℃ for 15 min,the ratio of ginsenoside Re to glycine is 0.53,and the peak area of ginsenoside Rk3 in liquid phase detection is 209 ± 4 m V*min.The optimal conversion process of ginsenoside20(S)-Rg2 is temperature 193℃ for 29 min,the ratio of ginsenoside Re to glycine is1.1,and the highest peak of ginsenoside 20(S)-Rg2 under liquid phase detection is obtained.The area is 1118 ± 13 m V*min.The optimal conversion process for20(R)-Rg2 is temperature 184℃ for 32 min,and the ratio of ginsenoside Re to glycine is 0.93.The highest peak of ginsenoside 20(R)-Rg2 is detected in the liquid phase.Peak area is 859 ± 9 m V*min.The optimal process conditions for conversion of ginsenosides Rg6 and F4 by single-factor experiments are that the temperature is180℃ and the time is 30 minutes,and the ratio of ginsenoside Re to glycine is 1.The third chapter uses ginsenoside Rb1 and Rg1 as the material and uses subcritical water for conversion.The extraction time,extraction temperature,and the ratio of ginsenoside Rb1 to glycine are selected as the influenced factors through a single factor experiment.The optimal conversion process of ginsenosides 20(S)-Rs3 and20(R)-Rs3 is optimized at a temperature of 156°C and a time of 13 minutes,and the ratio of ginsenoside Rb1 to glycine is 0.49.The optimal conversion process of ginsenosides 20(S)-Rg3 and 20(R)-Rg3 is temperature 160℃ for 50 min,and the ratio of Rb1 and glycine is 2.The optimal conversion process of ginsenoside Rk1 and Rg5 is temperature 220°C and for 30 min and the ratio of ginsenoside Rb1 to glycine has little effect on the experiment.Optimized process to obtain the best conversion of ginsenosides Rk3 and Rh4 is 220℃ for 20 min,and when the ratio of Rg1 to glycine is 1,the most ginsenosides Rk3 and Rh4 can be prepared.The optimal process for conversion ginsenosides 20(S)-Rh1 and 20(R)-Rh1 is 160℃ for 50 min,and the ratio of ginsenoside Rg1 to glycine is 1.The fourth chapter analyzes the trace constituents of rare ginsenoside directed conversion products in the first,second and third chapters.The structure fragments are studied by HPLC-Q-TOF-MS/MS technology,and the structure of the directional conversion products of rare ginsenosides is analyzed based on the ion fragments of the tandem mass spectrometry.Six rare ginsenosides were resolved from the targeted conversion products of ginsenoside Re,six rare ginsenosides were resolved from the targeted conversion products of ginsenoside Rb1,and four rare ginsenosides were resolved from the targeted conversion products of ginsenoside Rg1. |
