Studies On Magnetic Beads Based Approaches For Rapid Discovery Of Bioactive Compounds From Traditional Chinese Medicine

Screening bioactive compounds from traditional Chinese medicine (TCM) is one of the crucial parts in elucidating the material foundation of traditional Chinese medicine. It not only has great significance in the modernization of TCM but also is an important approach to discover new drugs.In this paper, we established two magnetic beads based approaches for screening bioactive compounds from TCM, including a magnetic bead based method for screening lipase inhibitors and magnetic nanoparticles beads based method for screening ligands of bovine serum album. The approaches exhibited several advantages over conventional bio-guided screening. Firstly, ligands of specific targets can be enriched and identified, which provided useful guidance for large-scale preparation of active compounds. Secondly, after coupled with high performance liquid chromatography-mass spectrometry, the approaches can isolate and identify bound ligands simultaneously, which greatly improve the efficiency of the screening. Lastly, structural and biological data of active compounds can be obtained simultaneously.We successfully applied the proposed approaches to identify 11 bioactive compounds from Fructus aurantii and Tongmai Yangxin pills. Moreover, the chemical composition of Tongmai Yangxin pills was also studied, in which 80 compounds were identified.The main contents of the thesis included:1. An lipase coated magnetic beads based screening approach was established and had been applied to discovering potential ligands of lipase from total flavonoid of Fructus aurantii. The structures of potential active compounds were putatively identified via liquid chromatography-mass spectrometry (LC/MS). The results demonstrated that four flavonoids (naringin, hesperidin, neohesperidin and poncirin) could bind to lipase, while only hesperidin, neohesperidin and poncirin exhibit lipase inhibitory activities in the conventional lipase inhibitory assay. Moreover, the inhibitory effect of poncirin on lipase was reported for the first time.2. The constituents of Tongmai Yangxin pills were characterized using high performance-liquid chromatography coupled with high resolution mass spectrometry. 80 compounds in Tongmai Yangxin pills were detected, including 23 flavones and their glucuronides,6 phenethylalcohol glycosides,20 triterpene saponins,15 lignans and 18 other compounds.3. A magnetic nanoparticles based screening approach was developed and had been applied to the Tongmai Yangxin pills. Bovine serum album (BSA) was selected as a target to establish the approach. Multiple parameters related to binding capacity including pH and ion strength of buffer, protein concentration, as well as size of nanoparticles were optimized. As a reulst, eight compounds from the Tongmai Yangxin pills binding to the target were found and characterized by via liquid chromatography-mass spectrometry (LC/MS). The interactions between BSA and two ligands (glycyrrhizic acid and emodin 8-O-?-D-glucopyranoside) were further conformed using spectroscopic method.