Study On The Mechanism Of Benzimidazole Anti-parasitic Drugs And Bovine Serum Albumin

Benzimidazoles?BDZs?anti-parasitic drugs are a broad-spectrum and highly effective anti-parasitic drugs,which are widely used in the prevention and treatment of parasites in agriculture and animal husbandry.However,BDZs will produce residues in the environment or animal foods such as meat,egg,milk,etc.Due to excessive use BDZs,BDZs will enter the human body through the food chain,combine with serum albumin?SA?and be transported to various tissues.According to related research,BDZs have biological toxicity,teratogenicity and embryo toxicity.Therefore,studying the interaction between BDZs anti-parasitic drugs and SA has certain reference significance for understanding the distribution,metabolism and toxicity of drugs in the organism.In this paper,the interaction mechanism between two typical BDZs antiparasitic drugs albendazole?ABZ?and fenbendazole?FBZ?with bovine serum albumin?BSA?,and their effects on BSA conformation were studied through multi-spectroscopy methods combined with molecular docking technology.The specific work content is as follows:1.The interaction mechanism between ABZ and BSA was studied by multi-spectroscopy methods.The results of fluorescence spectroscopy and time-resolved fluorescence spectroscopy indicated that the fluorescence quenching of BSA by ABZ was mainly static quenching.At 298 K,the binding constant between ABZ and BSA was 2.1×10⁵ L·mol^-1,indicating that a stable complex has been formed between the ABZ and BSA.The thermodynamic constant enthalpy and entropy were-171.6 kJ·mol^-11 and-473.9 J·mol^-1·K^-1,respectively,indicating that the interaction force between ABZ and BSA was mainly hydrogen bonding and van der Waals force.The result of competition experiments unveiled the binding of ABZ to BSA at site 1 located in subdomain IIA of BSA.The results of UV-vis spectroscopy,Synchronous fluorescence spectroscopy,three-dimensional fluorescence spectroscopy,fourier transform infrared spectroscopy and raman spectroscopy showed that ABZ induced conformational changes of BSA.2.The interaction mechanism between FBZ and BSA was studied by multi-spectroscopy methods and molecular docking experiments.The results of fluorescence spectroscopy experiments showed that the fluorescence quenching of BSA by FBZ was mainly static quenching and non-radiative energy transfer.At 298 K,303 K and 310 K,the binding constants of FBZ and BSA were2.7×10⁴ L·mol^-1,4.0×10⁴ L·mol^-1,8.5×10⁴ L·mol^-1;respectively,the enthalpy and entropy were 74.0 KJ·mol^-11 and 332.8 J·mol^-1·K^-1,indicating that FBZ and BSA form a complex through the hydrophobic force.The results of competition experiments and molecular docking experiments showed that FBZ was bound in the hydrophobic cavity of Site 1.The results of UV-vis spectroscopy and Synchronous fluorescence spectroscopy showed that FBZ had an effect on the micro-environment of tryptophan in BSA;IR spectroscopy and circular dichroism spectroscopy experiments showed that FBZ induced changes in the secondary structure of BSA and the content of?-helix decreased.3.The inclusion complex of FBZ and?-cyclodextrin??-CD?was prepared by the saturated solution method,and the inclusion ratio of the inclusion complex was determined to be 1:1 by the JOB curve and the phase solubility curve;The structure of FBZ-?-CD complex was characterized by scanning electron microscope?SEM?,fourier transform infrared spectroscopy?FTIR?,X-ray powder diffraction?XRD?,thermogravimetric analysis?TG?,nuclear magnetic resonance?NMR?,and molecular docking methods.its water solubility increased about 10 times.The fluorescence quenching constant and binding constant of the interaction between FBZ-?-CD supra-molecular system and BSA were studied by fluorescence spectroscopy.