RP-HPLC Determination of Glabridin Content in Different Licorice Residues from Glycyrrhiza glabra L

OBJECTIVE To use the RP-HPLC method for determination of glabridin content in different origines of Glycyrrhiza glabra L (licorice). METHODS Four samples of licorice residue were prepared from 4 origins of Glycrrhiza glabra L with same water extraction method; six samples of licorice flavonoid crude extracts were prepared from 4 samples of licorice residues with different extraction methods. The Symmetry C18 column was used for the determination of glabridin content; mobile phase was acetonitrile-water-glacial acetic acid (55∶44∶1); detection wavelength was 282 nm, column temperature was 30 ℃. RESULTS There was a good linear relationship when the concentration of glabridin was in the range of 0.09-0.45 mg·mL^-1(r=0.999 7). The average recovery rate was 100.2% and the RSD was 0.89%. The content of glabridin in the six samples was 1.31%, 1.16%, 1.59%, 2.93%, 0.98% and 0.85%, respectively; and the content of glabridin in four samples of licorice residue were 0.225%, 0.290%, 0.211% and 0.218%, respectively. CONCLUSION The detection by RP-HPLC is a simple and easy method for determination of Glabridin in Glycyrrhiza glabra. The glabridin content in Xinjiang Hejing licorice is higher than those of other sources. Furthermore, the reflux-extraction method by methanol is more effective method for increasing the extract yield and glabridin content than those of the extraction by ethanol or by ultrasonic methanol extraction.