Separation and determination of coumarins from Cacalia tangutica by capillary zone electrophoresis.
Capillary zone electrophoresis (CZE), using a 20 mmol/L borate buffer at pH 10.5, was developed for the identification and determination of three coumarins--7-hydroxy-coumarin (HC), 7-hydroxy-8-methoxy-coumarin (HMC) and 7-O-beta-D-glucosyl-coumarin (GC)--in the extracts of the flower of Cacalia tangutica. Regression equations revealed linear relationships (correlation coefficient 0.9986-0.9990) between the corrected peak area (the ratio of peak area to migration time) of each constituent and its concentration. The relative standard deviations (RSD) of the migration time and peak area were 1.45-1.52 and 2.60-3.84% (intra-day), and 1.75-2.22 and 2.90-4.04% (inter-day), respectively. The recoveries of three constituents ranged between 94.5 and 105.6%. The effects of pH value, buffer concentration and applied voltage on the migration behavior of HC, HMC and GC were investigated. The contents of the three active constituents in the flower of Cacalia tangutica were successfully determined within 6 min under the optimum conditions chosen. Moreover, the dissociation constants for three coumarins were also determined by CE.
Yue
Mei-E
ME
Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
Jiang
Ting-Fu
TF
Liu
Xia
X
Shi
Yan-Ping
YP
D003374:Coumarins / Q000032:analysis / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000379:methods*; D035264:Flowers / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010946:Plants, Medicinal / Q000737:chemistry*
D003374:Coumarins