Abstract:

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.

Key words: leaves of Xanthium L., total flavonoids, ultrasonic-assisted extraction, extraction process