Determination of gentiopicroside, mangiferin, palmatine, berberine, baicalin, wogonin and glycyrrhizin in the traditional Chinese medicinal preparation sann-joong-kuey-jian-tang by high-performance liquid chromatography.

High-performance liquid chromatography was employed to determine the contents of several marker substances such as gentiopicroside, mangiferin, palmatine, berberine, baicalin, wogonin and glycyrrhizin in Sann-Joong-Kuey-Jian-Tang. The separation was performed on a Cosmosil 5C18-AR column by gradient elution with 0.03% (v/v) phosphoric acid-acetonitrile (0 min, 90:10; 10 min, 87:13; 17-27 min, 77:23; 40 min, 62:38; 50 min, 55:45) as the mobile phase at a flow-rate of 1.0 ml/min, with detection at 254 nm. n-Propylparaben was used as the internal standard and seven regression equations revealed linear relationships between the peak-area ratios (marker substances/internal standard) and concentrations. The repeatability and reproducibility (relative standard deviation) of the method were in the ranges 0.02-1.78% and 1.44-4.95%, respectively.