摘要：In this research, the total flavonoids were extracted by ultrasonic extraction from the stem of Nicandra physalodes. Firstly, single factor analysis was used to optimize the effects of processing parameters including temperature, ultrasonic time, ethanol concentration, ultrasonic power and solid-liquid ratio on the total flavonoids yields. Based on single factor analysis, orthogonal experiment of L_(18) (3~5) was then designed and performed. Through statistical analysis, ratio of liquid to solid had significant effect on the yield of total flavonoids from Nicandra physalodes. In addition, the ethanol concentration, extraction time and temperature also played a role on the yields. Thus, the optimum extraction conditions were determined as follows: ratio of liquid to solid 1:20, extraction temperature 60 □, extraction time 40 min, ethanol concentration 40 % (v/v), ultrasonic power 150 w. Under these conditions, we obtained 2.80% extraction rate of total flavonoids.
