Fingerprint analysis and pharmacological study on the Chinese medicines : Radix Paeoniae Alba and Radix Puerariae Lobatae

Abstract

Traditional Chinese medicine (TCM) is getting more and more popular nowadays in the whole world for improving health condition of human beings as well as preventing and healing disease. The efficacies of TCMs can be reflected from their complicated multi-components nature. Chromatographic separation techniques used in analysis for TCM chemical components together with bioassays on studying of biological activities of these TCMs are desirable in order to find out the relationship between these chemical components and their corresponding efficacy. This relationship is useful to provide more scientific information for assessing the quality of TCMs. The solvent used for sample extraction largely determines the chemical composition of the TCM extracts obtained and its biological activity. Radix Paeoniae Alba (P. Alba) was investigated in this study to explore the effect of extraction solvent on the inhibitory hepatoma cells growth. Five extracts of P. Alba named PR0, PR25, PR50, PR75 and PR100 as prepared by a mixture of two solvents, were found to produce variation of the components in chemical profiles as detected by High Performance Liquid Chromatography with Diode Array Detector (HPLC-DAD). And they exhibited different antiproliferation activities on HepG2 cells but no obvious activity on Hep3B cells was found. Then we tried to link the HPLC-DAD chromatographic fingerprints of these extracts with antiproliferation activity on HepG2 cells. After finishing the above step through investigation of the pharmacological effect of P. Alba extracts, finding out the bioactive component or fraction of P. Alba that is responsible for the biological activity is the next one. The most potent PR100 among the five extracts was utilized to search for which bioactive component(s) or fraction(s) is/are responsible for HepG2 cells. One identified component and one fraction were found to have more effective growth inhibitory effect compared with PR100 itself. Another herb investigated in this study was Radix Puerariae Lobatae (P. Lobatae. Most studies reported that P. Lobatae is a rich source of isoflavonoids components that are very effective in cardiovascular diseases. This disease is mainly attributed to antioxidant activity of isoflavonoids. In this part, the optimized condition of extraction of P. Lobatae was established by the use of the uniform design having five variable parameters. They were solvents, solvent volume, temperature, extraction time and number of repeats of extraction. The condition was optimized on the contents of isoflavonoids detected by HPLC-DAD in line with the results of one antioxidant test which was 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. The results found that 180ml of 100% methanol in two times of 75 min at 50oC was the best condition for P. Lobatae. This study provides a model system for setting up the quality assessment based on the identified chemical ingredients and their bioactivities of a TCM.