Study On The Interaction Between Polyphenols And Human Serum Albumin

Human serum albumin(HSA)is the most abundant transport protein,which possesses many important physiological and pharmacological functions and can combine with endogenous and exogenous molecules.It also plays an essential role as storage and transporter for these molecules to transpors them to the receptor site for exerting effect.This feature make it one of the most extensive model proteins for research.Most of the polyphenols are secondary metabolites of plants with potential biological activities,such as treatment of several diseases,prevention insect pests and UV defense.When interacting with HSA both of them will form a supramolecular complex,the plasma protein binding(PPB)rate and the combining strength of polyphenols in the process will affect its bioactivity.Figuring out the binding rules of both can not only providing important reference data for clinical medicine and nutrition also contributing better understanding the metabolic process of polyphenols in vivo,the interactive mechanism between polyphenols and carrier proteins and the study about metabolic kinetics and toxicological properties of polyphenols.Furthermore,it will be of importance biologically and physiologically to explain the relationship between protein structure and function and to develope the new drug candidates.Presently,the research between small molecules and biological macromolecules gets increasing attention,the research methods are becoming rich and the research fields are expanding gradually as well,while the problem among the study is that the research method is single and many studies just pay close attention to the common questions,few literatures considering the protein binding rate and the factors that affect the protein binding rate;the relationship between the PPB and the affinity was rarely mentioned when small molecules interact with protein.Based on the significance and the research trend between small molecules and protein interaction,the interaction between polyphenols and human serum albuminwas studied from the following several aspects by high performance affinity chromatography(HPAC)and fluorescence spectroscopy(FS):1.Studying the interaction between polyphenols and HSA by high performance affinity chromatography,calculating the relative protein binding rate of each polyphenol according to the chromatographic theory and analyzing the relationship between structure and protein binding rate and the factors that can cause the binding rate difference.2.The binding force between polyphenols and HSA were investigated by fluorescence spectroscopy,the binding constants and binding sites of both were calculated according to the quenching equation.The causing reasons,the red or blue shifting of human serum albumin fluorescence emission spectra,the main force that cause the interaction between polyphenol and HSA,the relationship between the structure and affinity,were analyzed.3.The relationship between the binding rate and affinity of polyphenols and HSA were analyzed and discussed by the comprehensive results of high affinity chromatography and fluorescence spectrometry.This paper includes four parts:Chapter 1 mainly summarized the structure,classification and applications of polyphenol;introducing the nature,structure,function of the Human Serum Albumin;the methods to study the interaction between small molecules and biological macromolecules and the research status of them.Chapter 2 described the relationship about the polyphenols-protein binding rate.The results of the high affinity chromatography showed that the retention time of polyphenol can be used for analysis;Polyphenols and HSA could bind each other obviously and the binding rate of polyphenols with HSA were various;The different structure groups affected the binding rate apparently;the methylation decreased the PPB of polyphenols,the hydroxylation on ring-A generally increased the PPB,while the hydroxylation on the ring-B will reduce this effect,the hydrogenation of C2=C3double bond and the glycosylation of the polyphenol decreased the protein binding rate.Chapter 3 discussed he relationship between the polyphenols and protein binding force.The results of the fluorescence showed that the fluorescence quenching effect of polyphenols on HSA was obvious,the maximum fluorescence emission of HSA accompanied by red shift or blue shift in some degree;The fluorescence quenching ofeach polyphenol on HSA was different and the fluorescence quenching effect increased with the concentration increased of polyphenols.The methylation enhanced the binding force of polyphenol on HSA,the effect of hydroxylation is complicated,the hydrogenation of C2=C3 double bond and glycosylation to polyphenol decreased the affinity for HSA.Finally,the relationship between PPB and binding force was discussed,the result showed that there was certain correlation between the binding force and PPB.Chapter 4: Summary and outlook.