Study On Extraction, Isolation And Antioxidative Activity Of The Flavonoids From Glycyrrhiza Uralensis

Glycyrrhiza is the dried roots and rhizomes of leguminous plant Glycyrrhiza inflata Bat or Glycyrrhiza glabra L,which reconcile the various drugs,detoxication,tonic,and lungs cough. The article compared a variety of extraction methods to flavonoids from Glycyrrhiza,and optimized the extraction methods,separated and purified flavonoids from Glycyrrhiza exploit HPCPC, the antioxidant activity of flavonoids from Glycyrrhiza is evaluated using activity experiments,provided the experimental evidence and theory to research and development with flavonoids from Glycyrrhiza.Firstly,we compared and researched the methods of extraction to flavonodis from Glycyrrhiza by ultrasonic extraction,reflux extraction,soaking extraction and accelerated solvent extraction,selected and optimized the extraction of accelerated solvent extraction and reflux extraction,determined the best extraction method.The results show that extraction efficiency of flavonodis from Glycyrrhiza with accelerated solvent extraction is higher than other methods,the extraction time is 7 minutes,extraction temperature is 120℃,extraction times is once,ethanol concentration is 70 %,the above-mentioned are the optimum extraction condition of accelerated solvent extraction.The ethanol concentration is 80 %, extraction time is 1.5 hours, extraction times is three times, the above-mentioned are the optimum extraction condition of reflux extraction.Secondly,we developed HPCPC to isolate the flavonoids from Glycyrrhiza.Separated the flavonoids from Glycyrrhiza at two detection wavelength of 276 nm and 360 nm, respectively. At the detection wavelength of 276 nm,the solvent system is ethyl acetate: ethanol: water (1:0.1:1, V/V/V),we can separate two single compounds from Glycyrrhiza, Liquiritigenin-4'-apiosyl-glucoside and Liquiritin,the purity achieved 95 % and 97 %, respectively. At the detection wavelength of 360 nm,the solvent system is ethyl acetate:methanol:water (1:0.1:1, V/V/V), we can separate two single compounds from Glycyrrhiza,Licuraside and Isoliquiritin, the purity achieved 92 % and 91 %, respectively. The third,the antioxidant activity of various extraction methods and concentration from Glycyrrhiza is evaluated using three medthods,which scavenging DPPH·,O₂^-·and H₂O₂.The results show that the total flavonoids from Glycyrrhiza have effect on scavenging DPPH·, O₂^-·and H₂O₂,with increasing of the sample concentration,the scavenging has strengthening, the scavenging of accelerated solvent extraction is higher than other extraction methods,the scavenging O₂^-·,and H₂O₂ of Glycyrrhiza extraction is higher than Vc.