Flavonoids were extracted from Graptopetalum paraguayense leaves via ultrasonic-assisted etha-nol extraction,which exhibited significantly higher yields in comparison with traditional methods involving methanol and ethanol extraction.The main factors were investigated by one factor test and response sur-face methodology.The results showed that the optimal conditions were as follows:ultrasonic time 41 min,temperature 54 ℃,liquid-solid ratio 16∶1(mL∶g),ethanol volume fraction 85％and ultrasonic power 250 W.Under these settings,the yield reached 2.4％.
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