Objective: The stable quality of Chinese herbal medicines is a critical factor for their reliable clinical efficiency. An improved liquid-liquid extraction procedure and a liquid chromatographic method were developed to simultaneously analyze five anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) in a Chinese traditional hospital preparation, Fuyankang mixture, in order to quantitatively control its quality in a more effective way.
Methods: A more economical and repeatable extraction procedure based on conventional liquid-liquid extraction technique was developed and used to extract five marker components in Fuyankang mixture. These anthraquinones were separated in less than 20 min on a C18 column with methanol and 0.1% phosphoric acid (88:12, v/v) as mobile phase. The method was validated for specificity, precision, spiked recovery and stability.
Results: Compared to conventional liquid-liquid extraction, the improved liquid-liquid extraction was found to be more effective for simultaneous extraction of anthraquinones from an aqueous Chinese herbal preparation, especially for hydrophobic compounds. The improved extraction method was successfully applied to determine the content of five marker components in Fuyankang mixture by the means of reverse phase high-performance liquid chromatography.
Conclusion: The improved extraction procedure may be suitable for routine quality control of Fuyankang mixture and other traditional preparations at city-level hospitals in China.