Recognition Study On Nitrogen Heterocyclic And Cyclodextrin/biological Macromolecules Based On NMR Technology

Human serum albumin(HSA),the most abundant carrier protein in plasma,could bind many endogenous and exogenous compounds.The IIA and IIIA regions of HSA are the main binding sites of drug molecules,it is helpful for the design and application of new drugs to research the interaction between HSA and drug molecules,so HSA is also known as "the second step in ideal drug design".Cyclodextrin,as the second generation of supramolecular compounds,with the proper cavity,can include many kinds of hydrophobic organic compounds,inorganic compounds,ions and even gases.In addition,cyclodextrin is widely used in various fields,especially in medicine because of its low hemolysis,low irritation and high solubilization.In this paper,the recognition of a series of nitrogen-containing heterocyclic compounds and cyclodextrin and its derivatives and HSA was stuedied by a series of nuclear magnetic resonance experiments.The recognition interaction and recognition sites of nitrogen-containing heterocyclic compounds and HSA were analyzed by measuring thier binding constants and identification orientation.The results showed that a series of nitrogen-containing heterocyclic compounds are all capable of binding in the IIIA region of HSA to form complexes in mixed solvent.And then taking advantage of cyclodextrins,the nitrogen-containing heterocyclic compounds were prepared into water-soluble inclusion and analyzed by nuclear magnetic resonance method(NMR),infrared spectra(IR),thermogravimetric(TG),X-ray diffraction(XRD)and scanning electron microscopy(SEM),which demonstrated that the inclusion could improve the water solubility and stability,and hydrophobic interaction was the major interaction force in molecular recognition.Finally,the interaction between cyclodextrin inclusion complex and HSA was studied by means of nuclear magnetic resonance saturation transfer differential spectroscopy and diffusion experiment.The experiment results exhibited that the inclusion significantly improved the recognition effect of carbendazim and lomustine with HSA,cyclodextrin performed an excellent translocation and targeting in the ternary recognition system.Study of the interaction between nitrogen-containing heterocyclic compounds with cyclodextrin and HSA contribute significantly in improving their bioavailability,solving the problem of soil restoration and providing new ideas and methods for the rational use of pesticide.Meanwhile,it could play a guiding role in the design of new drugs and extend the application range of cyclodextrin.