ABSTRACT
Objective To establish the quality standard of flavone extracts in licorice residue; To provide the methods and basis for the quality control of total flavonoids extracted from licorice residue.Methods TLC was applied to compare the extracts with liquiritin and licorice; UV-spectrophotometry was used to measure the content of total flavones; EDTA-2Na titration was used to determine the content of calciumion.Results In the chromatogram of the test product, the spots of the same color were displayed on the corresponding position of the control medicinal material, and the fluorescent spots of the same color were displayed on the corresponding position of the control product. UV-spectrophotometry showed glycyrrhizin had a good linear relationship in the range of 3.32–9.96 μg/mL (r=0.9997), the absorbance between 0.3 and 0.7. The average recovery rate was 102.41% (RSD=3.22%), and the average content of total flavonoids in three batches of flavonoids extract was 8.82%. The average content of calciumion was 0.107% (RSD=3.61%).Conclusion This method has good repeatability, high sensitivity and accurate results, and can be used for the quality control of flavonoids in licorice residue.