Objective: To establish a method for simultaneous determination of the six flavonoid active components (hyperoside

isoquercitrin

astragalin

quercetin

kaempferol and isorhamnetin) in Semen Cuscutae by UPLC. Method: A quantitative method was developed for simultaneous determination of the six flavonoid active components with Semen Cuscutae from Inner Mongolia as a representative. Agilent Eclipse Plus C18 column (2.1 mm×50 mm

1.8 μm) was used with the mobile phase of acetonitrile-0.1% formic acid solution for gradient elution

at a flow rate of 0.21 mL · min-1. The column temperature was kept at 30 ℃ and the wavelength was set at 360 nm. Result: Hyperoside

isoquercitrin

astragalin

quercetin

kaempferol and isorhamnetin showed good linearity in range of 0.046 8-0.748 8 μg(r=0.999 9)

0.024 2-0.387 2 μg(r=0.999 9)

0.088 2-1.411 2 μg(r=0.999 9)

0.002 3-0.037 0 μg(r=0.999 7)

0.028 8-0.460 8 μg(r=0.999 6) and 0.002 3-0.037 0 μg (r=0.999 4) respectively. The detection limit of six flavonoids was 0.292 5

0.302 5

0.367 5

0.289 0

0.360 0

0.286 0 mg · L-1

and their limit of quantification was 0.877 5

1.210 0

1.470 0

1.012 0

1.260 0

1.215 5 mg · L-1 respectively. Their average recovery rate was 99.95%

99.78%

99.53%

99.38%

100.03% and 99.35% with RSD of 1.0%

1.2%

1.0%

1.4%

1.1% and 0.5% respectively. There was great difference in contents of the six flavonoid active components between 12 kinds of Semen Cuscutae from different origins. Conclusion: This method is specific

reproducible

rapid and controllable

and provides basis for scientific evaluation and quality control of Semen Cuscutae.