ABSTRACT
OBJECTIVE： To optimize the extraction technology of the flavonoids from Glycyrrhiza uralensis. METHODS： Using total contents of four flavonoids， liquiritinapioside， glycyrrhizin， isoliquiritin apioside and formononetin as indexes， types and volume fractions of extraction solvents （water， ethanol）， volume of addition and extraction time as factors， based on single factor experiment， Box-Behnken design-response surface method was used to optimize the extraction technology of flavonoids from G. uralensis. Validation test was also conducted. RESULTS： The optimal extraction technology was 50 mL 50％ ethanol as extraction solvent， 0.200 g G. uralensis， ultrasonic extraction for 50 min. In validation test， the extraction amounts of liquiritinapioside， glycyrrhizin， isoliquiritin apioside and formononetin were 10.733 0， 27.784 9， 3.441 9， 0.429 1 mg/g， respectively （all RSDs＜3.0％， n＝3）. The average total extraction amount of four flavonoids was obtained was 42.388 9 mg/g， the relative error of which to predicted value （42.173 2 mg/g） was 0.52％ （n＝3）. CONCLUSIONS： The optimized extraction technology is simple， rapid and stable， and can be used for the extraction of flavonoids from G. uralensis.