Study On The Interaction Between Flavonoids And Serum Albumin

The natural active compounds that are abound in nature and possess various favorable biological effect in remedy of many diseases. The Serum albumin is the most and important and abundant carrier protein in blood circulation, which are also the most plentiful depot and transport protein in blood plasma. Therefore, the study of the interaction between active compounds and serum albumin are distinctively important reference value for pharmacokinetics, biochemistry, pharmaceutics and clinic medicine.The reaction mechanism of flavonoids with protein were studied by fluorescence spectroscopy (FS) and UV-vis spectroscopy (UV) and interaction of molecules with bovine serum albumin (BSA) were investigated. This paper has two parts:1. the recent development and significance of interaction between flavonoids with BSA were introduced; 2. study on the interaction between several natural reactive molecules and BSA in simulation of human physiology (pH=7.4).The effect site of the flavonoids interaction with BSA were studied through testing several flavonids having simiar interaction eith BSA. The results showed that the 3 and 6 site of flavonids were the effective sites that interaction with BSA, and different inftuence way and different groups in different sites had different influence on the BSA, the number of hydroxy in group also effect the interaction the flavonids with BSA. In addation, the interaction of compounds with BSA were also researched.Part One In this section, the structures, functions and natures of proteins were introduced briefly first. Then the contents and methods of interaction of small ligands with serum albumin were reported. Last the existent problems also were emphasized and look into the distance of the study on the molecules and BSA.Part Two In part two, the binding interaction of two active natural molecules Daphnodorin A(DPA) and Daphnodorin B (DPB) with BSA were studied by fluorescence and UV-vis spectroscopy. The quenching mechanism of fluorescence of BSA by DPA and DPB were investigated, the result showed the quenches mechanism is static quenching. The binding constant K and binding sites number n were measured by fluorescence quenching method. Thermodynamic parameters obtained from measured date (ΔG,ΔH,ΔS) and principal binding. The binding distance between BSA and DPA and DPB were determined based on Forster theory. In addition, the effects of some metal ions on the binding of DPA and DPB with BSA were also studied. Through study on the BSA with DPA and DPB, it can speculate that the 5'of the flavonoids is an effect part.Part Three In part three, the interactions of four different Isorhamnetin-glucosides with BSA in pH 7.4 Tris-HCl buffer has been investigated with the use of spectrofluorimetry. The quenching mechanism of fluorescence of BSA with four small molecules were found to be static quenching. The binding constant K and binding sites number n were measured by fluorescence quenching method. Thermodynamic parameters obtained from measured date and principal binding. The binding distances between BSA and DPA or DPB were determined based on Forster theory. The result shows that four Isorhamnetin-glucosides which the 5'have the most hydroxyl have the biggest binding constant with BSA.Part Four In part four, the interaction of Acacetin (ACA) and Pectolinarigenin (PEC) with BSA under simulated physiological conditions were investigated by means of fluorescence spectroscopy. The result shows that two small molecules quenched the intrinsic fluorescence of BSA by static quenching mechanism, and from the thermodynamic parameters were calculated, it can be concluded that the hydrogen bonds and Van der Waals forces played a major role in the binding of ACA and PEC. In addition, different metal ion has effect on the drug-BSA. From the date it can speculated that the 6 of the flavonoids is an effect part.Part Five In part five, four ploretin mteal complex and four hydrazone mteal complex were synthesized, and study on the interaction of eight complexs with BSA under simulated physiological conditions. The result shows:the binding constants of ploretin metal complex-BSA system can be higher 1 order of magnitude than hydrazone metal complex- BSA system.