Studies on the interaction of tricyclazole with β-cyclodextrin and human serum albumin by spectroscopy

The interaction of tricyclazole (TCZ) with beta-cyclodextrin (beta-CD) and human serum albumin (HSA) were studied by fluorescence spectrum, UV-visible spectrum and second-order scattering technology. It was shown that TCZ has quite a strong ability to quench the fluorescence launching from HSA by reacting with it and forming a certain kind of new compound. The quenching and the energy transfer mechanisms were discussed, respectively. The binding constants and thermodynamic parameters at four different temperatures, the binding locality, and the binding power were obtained. The conformation of HSA was discussed by synchronous and three-dimensional fluorescence techniques. The inclusion reaction between beta-CD and TCZ was explored by scattering method, the inclusion constants and the thermodynamic parameters at 297 K and 311 K were figured out, respectively. The mechanism of inclusion reaction was speculated and linkage among the toxicity of TCZ, the exterior environment and its concentration was attempted to explain on molecule level.