Abstract: The methods of extraction and determination of the total flavonoids in the leaf-head of heading Chinese cabbages [ Brassica campestris ssp. pekinensis (Lour. ) Olsson ] were studied. The optimal
conditions for the ultrasonic extracting process were screened by single factor analysis and orthogonal analysis, which using 80% ethanol as impregnant, at the ratio 1 ∶20 of solid to liquid ( g/mL ) , the total flavonoids were extracted by 60 Hz ultrasonic at temperature 60℃ for 1 h, 2 times. Using rutin as standard
compound, the total flavonoids of orange colour Chinese cabbages were determined by UV spectrophotometry
and RP-HPLC, respectively. The result shows that RP-HPLC is better than spectrophotometrywith the same
trend. The condition of RP-HPLC is that a ODS column was used with methanol-water-acetic acid (6∶93.4
∶0.6) as the mobile phase, at a flow rate of 0.5 mL /min, 25℃ of the column temperature and 280 nm of
the UV detectection wavelength.

Key words: Chinese cabbage, Flavonoid, Ultrasonic, UV spectrophotometry, RP-HPLC