A Comparative Study of the Separation of Oleanolic Acid and Ursolic Acid in Prunella vulgaris by High-Performance Liquid Chromatography and Cyclodextrin-Modified Micellar Electrokinetic Chromatograph

H. Du and X.Q. Chen*

College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China

A high-performance liquid chromatographic (HPLC) method and a cyclodextrin-modified micellar electrokinetic chromatographic (CD-MEKC) method were developed to separate and determine oleanolic acid (OA) and ursolic acid (UA) in Prunella vulgaris. HPLC separations were carried out on a Hedera ODS C₁₈ column with methanol -H₂O- acetic acid (85:15:0.3, v/v/v) as mobile phase at a flow-rate of 0.8 ml min^-1. CD-MEKC analysis was performed on a CL1030 capillary electrophoresis system with a 6% (v/v) methanol solution (pH = 9.0) containing 10 mM disodium tetraborate, 10 mM sodium dihydrogen phosphate, 50 mM sodium dodecylsulfate (SDS), 15 mM 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) as background electrolyte. The analytical results of HPLC and CD-MEKC were compared with each other. CD-MEKC has better analytical efficiency for two components, and the analytical time (15 min) was shorter than that of HPLC (35 min)

Keywords: HPLC, CD-MEKC, Prunella vulgaris, Oleanolic acid, Ursolic acid