Separation and determination of phenylpropanoid glycosides from Pedicularis species by capillary electrophoresis

Capillary zone electrophoresis, using 30 mM borate buffer (pH 9.00) with 10% (v/v) methanol, was established for the identification and determination of four phenylpropanoid glycosides (PPGs)—echinocoside (ECH), verbascoside (VER), pedicularioside M (PED-M) and pedicularioside A (PED-A)—in extracts of Pedicularis longiflora var tubiformis, Pedicularis longiflora and Pedicularis Kansuensis. Regression equations revealed linear relationships (correlation coefficients: 0.9993–0.9999) between the peak area of each compound (ECH, VER, PED-M and PED-A) and its concentration. The relative standard deviations of the migration times and peak areas were <1.93 and 4.54%, respectively. The recoveries of four PPGs ranged between 95.6 and 108.4%. The effects of several CE parameters on the resolutions were studied systematically.