Simultaneous determination of five anthraquinones in a Chinese traditional preparation by RP-HPLC using an improved extraction procedure.

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.

[Comparison of three methods for quantitative analysis of LPO in different biological samples].

OBJECTIVE: To explore the optimized methods for detecting lipid peroxide (LPO) in biological samples and the reference value of LPO in human plasma. METHODS: Three most commonly adopted methods were used for detecting LPO in different biological samples simultaneously, and then their linearity, accuracy, precision, stability and detecting efficiency were compared. The methods were FOX assay, Modified iodometric assay and TBARS assay. The standard curve (linearity evaluation), rate of sample recovery (accuracy evaluation), reproducibility (precision evaluation), stability of reading number (stability evaluation), as well as the detected values of LPO in different sample systems by three methods simultaneously (detecting efficiency) were evaluated. The sample systems were: isolated low-density lipoprotein (LDL), supernatant of cell culture, and human plasma. RESULTS: When applied to detecting LPO in the isolated LDL sample system, FOX assay was found to have the most sensitive detecting efficiency, good accuracy and precision. When applied to detecting LPO in the supernatant of cell culture and human plasma sample systems, the Modified iodometric assay and TBARS assay showed better function than FOX assay; the rate of sample recovery of FOX assay 61.92% +/- 2.92% was obviously lower as compared with 99.00% +/- 2.65% of modified iodometric assay and 101.63% +/- 12.00% of TBARS assay; and the reproducibility of FOX assay 19.15% was also lower as compared with 4.36% of Modified iodometric assay and 3.14% of TBARS assay. The three methods all showed fine linearity and stability. The values of LPO concentration in normal human plasma were (14.189 +/- 4.889) mumol/L by Modified iodometric assay and (0.936 +/- 0.462) mumol/L by TBARS assay; these values were close to those in other reports. CONCLUSION: FOX assay was found to be most sensitive in the three methods for measurement of LPO in a relative pure sample system (such as isolated LDL). In complex sample system, however, the Modified iodometric assay and TBARS assay showed better function. The authors suggest that suitable method be chosen according to the nature of sample, that more than one method be chosen for plasma LPO assay in the same planned analysis, and that Modified iodometric assay and TBARS assay be worth the first choice.