Determination of oleanolic acid in Ligustrum lucidum and its medicinal preparation by capillary electrophoresis

A simple, rapid, accurate, selective and reproducible capillary electrophoretic method was developed for the assay of oleanolic acid in traditional Chinese herb Ligustrum lucidum and its medicinal preparation. The buffer solution used in this method was 10% acetonitrile and 0.010 M borax solution adjusted to pH 7.50 with 0.10M hydrochloric acid. The effects of pH value and modifier on the migration behavior of oleanolic acid was investigated and a simulated equation as well as the apparent dissociation constant were obtained. The linear calibration range was 0.040-1.50 mg/ml (r = 0.9979). The relative standard deviation of the migration time of oleanolic acid was 0.46% under the optimized conditions. The content of it in Ligustrum lucidum and a kind of Ligustrum lucidum-containing Chinese medicinal preparation was successfully determined within 4 min.