Separation Of The Epimers Of Glycyrrhizic Acid And Glycyrrhetinic Aicd By HPLC

The following aspects were discussed in this paper:1. The distribution of licorice root in China, biological activity compounds containing in licorice root, the application and the analysis methods of licorice root were introduced in this paper. The physicochemical property, application value, extracting and synthesis methods, analysis methods of the epimers of glycyrrhizic acids and glycyrrhetinic acids were expounded in this paper.2. The separation effect of the epimers of glycyrrhizic aicd by Phenomenex Luna C18 and Chromolith RP-18e column was compared. The effects of pH value, phosphate buffer concentration, acetonitrile content and column temperature on the separation of the epimers of glycyrrhizic aicd by a Chromolith RP-18e column were investigated. Baseline separation for these two epimers was achieved. The resolution was 2.75, and the runtime was finished in 10 minutes. The calibration curves were linear in the range of 2.12 μg/mL-21.2 μg/mL. The analysis efficiency was improved with this monolithic column. This method can be used to track the isomerization reaction of glycyrrhizic acid.3. The method for the separation of the 18-epimers of glycyrrhetinic acids was established by RP-HPLC, using Phenomenex Gemini C18 column as stationary phase, ammonium acetate-acetonitrile as mobile phase system. The effects of the content of ammonium acetate solution, the content of acetonitrile, pH value and column temperature on the separation of the epimers of glycyrrhetinic acid were discussed. The baseline separation was achieved for the epimers of glycyrrhetinic acid. The resolution was 3.91. The calibration curves of 18a-glycyrrhetinic acid and 18β-glycyrrhetinic acid were linear in the range of 2.24 μg/mL-24.64 μg/mL and 4.32 μg/mL-47.52 μg/mL, respectively. The R2 values of 18a-glycyrrhetinic acid and 18β-glycyrrhetinic acid were 0.998 and 0.996, respectively. The method for the separation of the epimers of glycyrrhetinic acid by RP-HPLC was convenient and rapid. This method can be used to quantify glycyrrhetinic acid drugs, track the configuration conversion of glycyrrhetinic acid.4. The synthesis of 18β-glycyrrhetinic acid and 18α-glycyrrhizic acid was studied in this paper. The effects of reaction temperature, reaction time, the concentration and volume of hydrochloric acid on the yield of 18β-glycyrrhetinic acid were invertigated by the RP-HPLC method. Then the optimum reaction condition was obtained. Under the optimum conditions, the purity and the yield of 18β-glycyrrhetinic acid were 90.3% and 84.3%, respectively.