Determination of andrographolide, deoxyandrographolide and neoandrographolide in the Chinese herb Andrographis paniculata by micellar electrokinetic capillary chromatography.

In this paper a micellar electrokinetic capillary chromatographic (MEKC) method has been developed for determining the active components (andrographolide, deoxyandrographolide and neoandrographolide) in water:ethanol extracts of the Chinese crude herb Andrographis paniculata and its preparations (Chuanxinlian and Xiaoyan Lidan tablets). The optimum separation conditions were 15 mM sodium dodecyl sulphate in 30 mM borate buffer (pH 9.5) with UV detection wavelength at 214 nm and a constant voltage of 16 kV. An HPLC method was employed in order to validate the MEKC method with respect to separation efficiency, sensitivity, linearity and repeatability. The two methods are shown to be complementary because of their different selectivity and thus are very suitable for cross-validation studies. The MEKC method is demonstrated to be more appropriate for the analysis of the active compounds in A. paniculata in that it is easier and less expensive to use and does not suffer from contamination of the chromatographic column.