Ultrasonic-assisted Extraction of Total Flavonoids from Leaves of Wild Xanthium L. Grown in Xinjiang

An ultrasonic-assisted extraction of total flavonoids from leaves of wild Xanthium L.grown in Xinjiang was developed.Single-factor method was adopted to investigate the effects of ethanol concentration,extraction temperature,ultrasonic treament time and material/liquid ratio on the extraction yield of total flavonoids.Subsequently,a four-variable/three-level orthogonal array design was carried out to maximize the extraction of total flavonoids.An extraction yield of total flavonoids of 3.10 mg/g was attained under the optimum extraction conditions as follows:ethanol concentration 50%,extraction temperature 30 ℃,ultrasonic treatment time 30 min,and material/liquid ratio 1:50.The ultrasonic-assisted extraction can be regarded as a purely physical process without any pollution,thus providing an ideal approach to extracting flavonoids from leaves of Xanthium L.