Identification and determination of ecdysones and flavonoids in Serratula strangulata by micellar electrokinetic capillary chromatography

The simultaneous determination of 20-hydroxyecdysone ( 1), 25-deoxy-11,20-dihydroxyecdysone ( 2), kaempferol 4',7-dimethyl ether ( 3) and biochanin A ( 4) in the fruit, leaf and root of Serratula strangulata Iljin has been investigated by micellar electrokinetic capillary chromatography for the first time. With an electrolyte containing 15 mmol/L borate, 60 mmol/L SDS, 20 % (v/v) methanol, at pH 9.08 and 20 kV applied voltage, the four analytes were completely separated within 22.7 min. The effects of concentration of borate, electrolyte pH, the concentrations of SDS and organic modifier and the applied voltage on electrophoretic behavior and separation were studied. Regression equations revealed linear relationships (correlation coefficients: 0.9986 - 0.9997) between the peak areas of the analytes and the corresponding concentrations. The levels of analytes in the different parts of S. strangulata were easily determined with recoveries ranging from 95.3 % to 104.0 %.