Extraction and Purification Techniques of Glycyrrhetinic Acid in Liquorice Extract

OBJECTIVE To optimize the extraction and purification techniques of glycyrrhetinic acid(GA) in liquorice extract. METHODS With the transfer rate and content of GA as the index, the crude extraction process of Glycyrrhiza uralensis was screened by single factor. Then the purification process of GA by anion exchange resin was further screened by single factor. RESULTS The extraction process of GA was determined as follows:The liquorice was immersed with 20% ethanol for reflux extraction 3 times, 10 times volume of liquorice each time, the extract was concentrated to 5 times volume of liquorice. Added 50% sulfuric acid, made the concentrate containing 5% sulfuric acid, heatedreflux for 5 h, abandoned the acid, washed to neutral and dry, porphyrized and liquorice obtained the GA extract. And the process of purification of GA was added appropriate amount of water to the extract, adjust pH to 11, made through the anion exchange resin column, added hydrochloric acid for acidification, eluted with 10 times 85% ethanol or more, evaporated ethanol under reduced pressure, filtered the precipitate, dry the filtrate below 50℃, obtained brown powder. The content of glycyrrhetinic acid was 55.5%, transfer rate was 53.3%. CONCLUSION The high content of GA obtained by the preparation indicates that the extraction and purification of GA by anion exchange resin is feasible.