Determination of liquiritin, glycyrrhizin, hesperidin, cinnamic acid, cinnamaldehyde, honokiol and magnolol in the traditional Chinese medicinal preparation Wu

A high-performance liquid chromatographic method for the determination of liquiritin, glycyrrhizin, hesperidin, cinnamic acid, cinnamaldehyde, honokiol and magnolol in a traditional Chinese medicinal preparation. Wuu-Ji-San, which contains Glycyrrhizae Radix. Citri Leiocarpae Exocarpium. Aurantii Fructus, Cinniamomi Ramulus and Magnoliae Cortex, was established. The samples were separated with a Cosmosil 5C18-AR column by linear gradient elution using 0.03% (v / v) phosphoric acid-acetonitrile (0 min. 95:5; 52 min, 30:70) as the mobile phase at a flow-rate of 1.0 mllmin and the eluate was detected at 254 nm. n-Propyl benzoate was used as the internal standard and seven regression equations showing linear relationships between the peak-area ratios of each marker to n-propyl benzoate and concentration were obtained. The recoveries of the markers listed above were 84.77, 87.07, 79.81, 72.71, 72.72, 77.15 and 73.74%, respectively. The relative standard deviations were less than 5% (n = 5). Very satisfactory and reproducible results were obtained within 52 min for the simultaneous determination of the seven markers. Different processes such as concentration by reduced-pressure evaporation, freeze-drying and spray-drying were studied with regard to their effects on the marker contents. There were only minor effects on most of the markers except cinnamic acid and cinnamaldehyde. Three commercial concentrated products of Wuu-Ji-San were also analysed. The contents of the marker substances in the commercial preparations were different from those in a standard decoction.