MECC determination of oleanolic acid and ursolic acid isomers in Ligustrum lucidum Ait.

In this paper, a novel method to separate and determine oleanolic acid and ursolic acid isomers in Ligustrum lucidum Ait was studied by micellar electrokinetic capillary chromatography (MECC). The baseline separation of the two analytes were obtained on the condition that the buffer contained 15 mmol/l disodium hydrogen phosphate, 15 mmol/l disodium tetreborate, 10 mmol/l SDS and 5% (v/v) alcohol. The contents of the oleanolic acid and ursolic acid were determined in L. lucidum Ait, Folium photiniae and Flos campsis; they were 78.3 (R.S.D. = 2.75%) and 20.7 mg/g (R.S.D. = 2.97%), 27.9 (R.S.D. = 3.67%) and 79.8 mg/g (R.S.D. = 3.44%), 65.5 (R.S.D. = 3.73%) and 60.4 mg/g (R.S.D. = 4.06%) (n = 5), respectively. The recoveries of the analytes in the extract of L. lucidum Ait were 102%, (R.S.D. = 2.85%) for oleanolic acid and 104% (R.S.D. = 3.21%) for ursolic acid (n = 5). With the emphasis on the effects of SDS and alcohol concentrations on the separation of the isomers were investigated.