The Study Of Binding Mechanism Between Four Plant Active Ingredients Of Ecotope And Serum Albumin

Research about the interaction between the active ingredient of plant and proteins in living body,the storage,transportation and metabolism approach of active ingredient of plant in vivo have become a hot issue in the field of research.The investigation of interaction between the active ingredient of plant and proteins is not only beneficial to understand the structure and function of them,but also provide theoretical guidance for targeted drug delivery.In this paper,we use spectroscopy experiment combined with molecular docking respectively exploring the interaction mechanism between four plant natural active ingredients and serum albumin.The four plant natural active ingredients are echinacoside(ECH)and its monomer verbascoside(VER),naringin(NAR1)and its aglycone naringenin(NAR2).The main results of this paper include the following sections:1.The established combination model of VER-HSA/BSA,ECH-HSA,NAR1/NAR2-BSA revealed that the interaction force of VER-HSA/BSA and NAR1-BSA are mainly hydrogen bonding and Van der Waals' forces;the interaction force of ECH-HSA and NAR2-BSA is mainly hydrophobic force.2.The results from fluorescence spectroscopy indicated that VER could bind to HSA/BSA to form static complex.The quenching between ECH and HSA is dynamic quenching.NAR1/NAR2 could bind to BSA to form complex,which comply with the theory of static quenching.3.According to the non-radiative energy transfer theory,the value of binding distances r of VER-HSA/BSA,ECH-HSA and NAR1/NAR2-BSA are less than 7nm,which indicate that there exists a phenomenon of radiation energy transfer between them.Through fluorescent phase diagram technical analysis,the reaction conformational pattern of VER-HSA/BSA,ECH-HSA and NAR1/NAR2-BSA show “two-state” model.4.The obtained thermodynamic parameters manifested that the main interactional force between VER-HSA/BSA and NAR1-BSA are mainly hydrogen bonding and Van der Waals' forces;the interaction force of ECH-HSA and NAR2-BSA is mainly hydrophobic force,which is consistent with the result of molecular docking.5.The fluorescence polarization proved that VER and HSA/BSA,ECH and HSA,NAR1/NAR2 and BSA generated non-covalent complex by interaction.6.The interaction between different ratio of NAR1,NAR2 mixtures and BSA demonstrated that the quenching intension of NAR2 is strong than NAR1 when their concentration are the same.In other words,naringenin is easier to combine with BSA than naringin.