CAPILLARY ELECTROPHORETIC ANALYSIS OF OXINDOLE ALKALOIDS FROM UNCARIA-TOMENTOSA

The main oxindole alkaloids from the root bark of Ucaria tomentosa were separated by capillary electrophoresis. The electrophoretic parameters for the separation of the six alkaloids were optimized by studying the impact of the buffer composition, the ionic strength and the pH and the applied electric field on the separation efficiency of the analytical system. The best separation was achieved with a fused-silica capillary tube and 20 mM phosphate running buffer (pH 5.6) at a constant voltage of 10 kV. The determination of oxindole alkaloids in a crude methanolic extract of Uncaria tomentosa demonstrates the applicability of this method.