Application Of β₂-adrenoceptor Affinity Chromatography In Screening Bioactive Components Of Traditional Chinese Medicine And Investigating Interactions Between Those Components

The study on the interaction between drugs and their receptors is of great importance for revealing the biological process of the drugs' influence in human body and also one of the hot topics in many fields, such as life science, chemistry, clinical pharmacology and so on.β₂-AR is a type of receptors that exists comprehensively in the smooth muscles of lungs and bronchus, one member of G-protein coupled receptors super family and the major target on which the common medicine for curing respiratory diseases can exert their influence. This thesis screens the active ingredients of rhizoma coptidis byβ₂-AR affinity chromatogram and makes profound study on the interaction between berberine hydrochloride in rhizoma coptidis andβ₂-AR as well as the interaction between jatrorrhizine hydrochloride andβ₂-AR by that method. The study has the prospect to provide new approaches for screening the active ingredients of Chinese medicine and revealing the mechanism of the interaction between the two alkaloids andβ₂-AR, which is very important for demonstrating their biological basis of functioning within human body. The full text falls into three chapters and the author's main contributions are as follows:Firstly, the active ingredients of water extract of rhizoma coptidis are screened byβ₂-AR affinity chromatogram. The conclusion is that the active ingredients that have specific interactions withβ₂-AR are the alkaloids, including berberine hydrochloride, jatrorrhizine hydrochloride and palmatine hydrochloride, which is potential for providing new approaches for high efficiency screening of the active ingredients in the complex systems, such as Chinese medicine. Secondly, the mechanism of interaction between the two kinds of isoquinoline alkaloid (berberine hydrochloride and jatrorrhizine hydrochloride) and immobilizedβ₂-AR is studied by competition elution method. The results are as follows:â‘ There is one type of binding sites in berberine hydrochloride that binds toβ₂-AR. The binding constant is 2.17×10⁴/M. The major pushing force in the binding process is hydrophobic interaction.â‘¡There is one type of binding sites in jatrorrhizine hydrochloride that binds toβ₂-AR. The binding constant is 2.54×10⁴/M. The major pushing forces in the binding process are hydrogen bond or Van der Walls force.â‘¢The two kinds of alkaloids compete for the same type of interacting sites onβ₂- AR affinity chromatogram column. The above study indicates thatβ₂-AR affinity chromatogram can be used for studying the mechanism of the interaction between drugs and proteins, receptors included.