Simultaneous Extraction Of Glabridin And Glycyrrhizic Acid From Glycyrrhiza Glabra L.

As a traditional chinese medical herb, Glycyrrhiza contains some active ingredients such as Glycyrrhizin, Glycyrrhetinic acid, flavonoids and polysaccharides. In the exploitation of Glycyrrhiza glabra L., it was great waste of natural resources that discarding flavonoids (especially Glabridin with high bioactivity) as dregs after extracting Glycyrrhizic acid. In order to increase the utilizing efficiency and expand the products chain of Glycyrrhiza, the technology of simultaneous extraction and purification of Glabridin (GB) and Glycyrrhizic acid (GA) from Glycyrrhiza glabra L.was studied in this article.First, the extraction of GB and GA was studied. Ethanol mixed with ammonia was chose in extraction. The single factor experiments and the orthogonal tests were done to optimize the refluxing extracting conditions as follows: 60% ethanol containing 0.6% ammonia as extractant, ratio of material to liquid 1:20 (w:v), extraction temperature 80oC, and extraction time 2h. Under these conditions, the extraction rates of GB and GA were 0.238% and 5.08%, the content of them were 6.296mg/g and 0.134g/g respectively. The ultrasonic-assisted extraction was also studied. The results showed that the extraction rates of GB and GA were 0.249% and 5.42%, the content of them were 8.539mg/g and 0.186g/g respectively in the conditions of ultrasonic power 150W, ultrasonic temperature 50oC, ultrasonic time 75min and ratio of material to liquid 1:15 (w:v).Secondly, the separation of GB and GA was studied. Ethyl acetate was selected as extractant. Under the optimal conditions: the crude extract concentrated to 1/4, extraction times 4 by 1:1 (v/v), the extraction rate of GB was 90.4% with content of 40.6mg/g and the retention rate of GA was 94.9%. GB and GA were nearly separated.Finally, further purification of both was studied. Polyamide column (20mm×300mm) chromatography was used to purify GB as follows: the concentration of sample 25mg/mL, the flow velocity 2mL/min. Impurities were removed by 40% ethanol and then 50% ethanol was collected. After vacuum concentration and freeze drying, brick-red power was obtained. By LC-MS/MS, the purity of GB was 53.4% more than that of existed product in the market, the purified multiple reached up to 85 compared to crude extract. The method of acid precipitation was chose to purify GA. In the conditions of pH=2 and 0-4oC, the GA was precipitated. Then ammonia was added to the extracting solution which come from precipitate extracted by 95% ethanol to make pH=7.5. At last, the triammonium glycyrrhizinate (TG) generated by ammoniation was dissolved in acetic acid at 70oC and then by cooling and standing, the monoammonium glycyrrhizinate (MG) crystallized. The purity of MG was 85.7%, and the recovery of it reached to 71.2%.