Abstract: The objective of this study was to determine the optimum ultrasound-assisted extraction condition for total flavonoids from Radix scutellariae. Extraction of total flavonoids from Radix scutellariae were carried out with ultrasonic-assisted technology, and the total flavonoids content was determined using sodium nitrite-aluminum nitrate colorimetric method. Via single factor and orthogonal experiments, the optimum extraction process of total flavonoids from Radix scutellariae was determined as followed: ethanol concentration was 50%, sonication time was 25 min, material-liquid ratio was 1∶25, and sonication temperature was 70 ℃. Under these conditions, the obtained total flavonoid extraction quantity was 15.15 mg/g.

Key words: Radix scutellariae, total flavonoids, ultrasound assistance, orthogonal test