Study On The Interaction Between Some Flavonoids Active Components In Natural Products And Proteins

In this thesis, the interaction between several flavonoids active component andbovine serum albumin(BSA), human serum albumin (HSA) and lysozyme(LYSO) inphysiological buffer (pH=7.4) was investigated by fluorescence spectroscopy andUV-Vis absorption spectroscopy. The work according to several studies such asquenching and conformatin change of protein,information changes and the effect ofmetal ions or adscititious reagents on the interaction between small medicinalmolecules and protein is worthy to be done not only benefits understanding thetransports, metabolic, reaction mechanism of drugs and structural features of proteinbut also provides important information on the design, compound and exploiting newdrugs.The thesis consists of five parts as follows:1.In this chapter, The structures and functions of BSA, HSA and LYSO wasintroduced. The methods of the research and the development in recent years on theinteraction between active components in natural products and somebiomacromolecules such as protein have been expatiated. This thesis was developedbased on the apply actuality of fluorescence spectroscopy and UV-Vis absorptionspectroscopy especially in this research field.2. At different temperature, the Interaction feature of hesperidin to BSA wasstudied by fluorescence quenching spectra, three-dimensional fluorescence spectra,synchronous fluorescence spectra and UV-Vis absorption spectroscopy. It was provedthat only dynamic quenching exits between hesperidin and BSA. According to thethermodynamic parameters, it shows that binding power between hesperidin and BSAis mainly the hydrophobic interaction. The effect of hesperidin on the conformation ofBSA analyzed by three-dimensional fluorescence spectra, contour spectra andsynchronous spectra.3. The interaction between alpinetin and HSA was studied by fluorescencespectroscopy and UV-Vis absorption spectroscopy. The results revealed that alpinetin caused the fluorescence quenching of HSA through a dynamic quenchingprocedure. The quenching constant was obtained at various temperature. Thebinding locality was an area 4.05 nm away from tryptophan residue in HSA basedon F(?)rster's non-radiation energy transfer mechanism. The binding power betweenalpinetin and HSA is mainly the hydrophobic interaction according to thethermodynamic parameters. It is proved that the alpinetin has effection on thesecond conformation of HSA by three-dimensional fluorescence spectra andsynchronous spectra.4. The interaction between irisflorentin (IFR) and BSA was studied byfluorescence spectroscopy and UV-Vis absorption spectroscopy; The resultsrevealed that IFR caused the fluorescence quenching of BSA through a dynamicquenching procedure;The quenching constant is 3.932×10⁴ L·mol^-1 at roomtemperature; The effect of irisflorentin on the conformation of BSA analyzed bythree-dimensional fluorescence spectra and synchronous spectra; The effect ofmetal ions Fe³⁺,Ca²⁺,Cu²⁺ or Mn²⁺ and adscititious reagents KI,SB or Glucose onthe interaction characteristic between BSA and IFR was investigated such as thechange of quenching mechanism of fluorescence, the interaction forces, theconformation of BSA, the association constant and the binding site.5. The interaction between Kaempferol and LYSO was studied by fluorescencespectroscopy and UV-Vis absorption spectroscopy;The results revealed thatKaempferol caused the fluorescence quenching of LYSO through a dynamicquenching procedure; The binding power between Kaempferol and LYSO is mainlythe hydrophobic interaction according to the thermodynamic parameters; The changeof quenching mechanism of fluorescence and the interaction forces and theconformation of LYSO by Kaempferol in the presence of metal ions and adscititiousreagents was also be studied.