Interaction Between Coumarins And Charles Ketone Compounds With Biological Macromolecules And Their Structure-activity Relationship Study

Objective The interaction and the structure-activity relationship of imperatorin, isoimperatorin,chalcone, 4′-methoxychalcone and 4′-chlorochalcone with DNA, bovine serum albumin(BSA), human serum albumin (HSA) and lysozyme (LYSO) were investigated under simulativephysiological condition. A fluorescence method for determination of HSA in biological samplewas developed based on the interaction between five compounds and HSA.Methods The changes of the UV-vis absorbance before and after the interaction of imperatorin,isoimperatorin with DNA were studied by the ultraviolet difference spectra. The correlatingparameters and the interaction force of the interaction of imperatorin and isoimperatorin withDNA were obtained by the fluorescence spectroscopy and the influence of seven metal ions suchas Mg²⁺ on the interaction of imperatorin and isoimperatorin with DNA was investigated.Futhermore, the binding mode of imperatorin, isoimperatorin and DNA were determinated bythe salt effect, DNA thermal denaturation and viscosimetry.The changes of the UV-vis absorbance before and after the interaction of imperatorin,isoimperatorin, chalcone , 4′-methoxychalcone , 4′-chlorochalcone with serum albumin (SA),three chalcone s and LYSO were studied by the ultraviolet difference spectra. The correlatingparameters and the interaction force of the interaction of five compounds and SA, threechalcone s and LYSO were obtained by the fluorescence spectroscopy. The influence of sevenmetal ions such as Mg²⁺on the interaction of five compounds with SA and the interaction of threechalcone s with LYSO were investigated. The effects of five compounds on the conformation ofSA and three chalcone s on the conformation of LYSO molecular were investigated bysynchronous fluorescence.The content of HSA in biologic al sample was determined by fluorescence spectroscopybased on the interaction between five compounds and HSA.Results The 1:1 compounds were formed between five compounds and metal ions. The results ofultraviolet spectroscopy showed that in the presence of DNA,the hypochromis ity was observedon the absorption spectra of imperatorin and isoimperatorin. The fluorescence of BR-DNA wasquenched with addition of imperatorin and isoimperatorin, which indicated that a strongcompetition for DNA binding between imperatorin (isoimperatorin) and BR existed. At the sametime, the viscosity of DNA was increased first and decreased then with the increase of theconcentration of imperatorin or isoimperatorin.The results of ultraviolet spectroscopy indicated that five compounds and SA, threechalcone s and LYSO all had interactions. The results of fluorescence spectrometry showed thatthe fluorescence of three globulins had been significantly quenched by five compounds. Themechanism of fluorescence quenching were static quenching with non-radiation energy transfer and the major driving force were hydrogen bond and Vander Waals. The binding parameters offive compounds and SA were as follows: for BSA, the binding constants K were 1.48×10⁴,1.04×10⁴, 3.16×10⁵, 3.02×10⁵ and 2.94×10⁵ L·mol^-1, the numbers of binding sites were 0.915,0.742, 0.996, 0.999 and 0.991 , the binding distances r were 0.73, 0.66, 3.35, 3.22 and 3.39nm,respectively; for HSA, the binding constants K were 2.45×10³, 2.27×10³, 2.50×10⁴, 6.97×10³ and2.77×10³ L·mol^-1, the numbers of binding sites were 0.930, 0.776, 1.00, 0.980 and 1.02, thebinding distances r were 2.97, 2.74, 3.93, 3.78 and 4.25 nm, respectively. The bindingparameters of three chalcone s and LYSO were as foll ows: the binding constants K were2.90×10⁴, 2.08×10⁴ and 1.29×10⁴ L·mol^-1, the numbers of binding sites were 0.713, 0.787 and0.654, the binding distances r were 4.23, 4.45 and 4.25nm, respectively. The results ofsynchronous fluorescence demonstrated that the conformation of SA was changed by fivecompounds and the conformation of LYSO was changed by three chalcone s.The fluorescence method has been applied to determin e the content of HSA in biologicalsample. RSD were 3.7%, 2.9%, 2.2%, 1.4%, 2.0% and the recovery were (98.5±3.67)% , (99.5±2.92)% , (99.6±2.14)% , (100±1.4)% and (99.7±2.03)%, respectively.Conclusion Both imperatorin and isoimperatorin had an interaction with DNA. The interactionsbetween imperatorin and isoimperatorin with DNA were influenced differently by metal ions.The results of DNA denaturation temperature test, salt effects and viscosimetry demonstratedthat the binding mode of imperatorin and isoimperatorin with DNA were the intercalation andelectrostatic interaction.Five compounds all had interactions with SA and three chalcone s had interactions withLYSO. The interactions of five compounds with three globulins were influenced differently byseven common metal ions.The fluorescence method for determination of HSA in biological sample was simple and highsensitive, which provide a new method for the determination of HSA.