ABSTRACT
Objective To establish a combined quality evaluation model of fingerprint and quantitative analysis of multi-components with a single-marker (QAMS) to analyze the total flavonoids from licorice residue by the chemical conversion method; To provide technical support for quality control in production. Methods Total flavonoids of breaking cell wall and enriching were taken as the object of study to establish fingerprint. With liquiritin as internal reference, the relative correction factors of isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid were established respectively, and the contents were determined. Meanwhile, the calculated values were compared with the measured value by external standard method to verify the practicability and stability of QAMS. Results The HPLC fingerprint of total flavonoids from licorice residue was established. 11 common peaks were identified, and 5 common peaks were identified, and the similarity of the 10 extracts was >0.99; the relative error between the calculated results of QAMS and the measured values of the external standard method was <4%; the RSD of relative correction factor calculated by the multiple concentration method was <2%. Conclusion The method is accurate, reliable, specific, and stable, with good repeatability, which can be used for the quality control of total flavonoids from licorice residue.
ABSTRACT
Objective To establish a method for the simultaneous determination of liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid in licorice extract. Methods Liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid in licorice extract were determined by HPLC dual wavelength spectrophotometry. Symmetry C18 column (4.6 mm × 250 mm, 5 μm) was used. The mobile phase was acetonitrile (A) - 0.085％ phosphoric acid water (B), ingradient elution mode (0–8 min, 81％ B; 8–35 min, 81％→50％ B; 35–60 min, 50％ B) with the flow rate of 1.0 mL/min. The sample size was 10 μL, and column temperature was room temperature. Dual wavelength detection, λ1=237 nm, λ2=254 nm. Results Liquiritin, isoliquiritin, glycyrrhizin, isoliquiritigenin and glycyrrhizic acid were linear in the ranges of 0.0408–0.816 μg, 0.0528–1.056 μg, 0.0224–0.448 μg, 0.0212–0.424 μg, and 0.0448–0.896 μg, respectively. The average recovery was 98.69％, 98.31％, 99.10％, 98.55％, and 99.14％, respectively; RSD was 1.39％, 1.29％, 1.78％, 2.14％, and 1.15 ％, respectively. Conclusion The method is accurate, reliable and specific. The results are stable with good repeatability. It can be used for the determine of above 5 components in licorice extract.