Spectroscopic, Docking and Molecular Dynamics Simulation Studies on the Interaction of Etofylline and Human Serum Albumin

The purpose of this study is to investigate the interaction of Etofylline as an established drug for asthma remedy, with the major transport protein in human blood circulation, the human serum albumin (HSA). In this respect, the fluorescence and circular dichroism (CD) spectroscopy techniques, along with the molecular docking and molecular dynamics simulation methods were employed. Analysis of the fluorescence quenching data with the Stern-Volmer equation, confirmed the static quenching mechanism due to the Etofylline-HSA complex formation. Calculated thermodynamics parameters (ΔH 0) indicated that the binding mechanism is both enthalpy and entropy driven, while simultaneous hydrophobic and hydrogen bonding interactions are involved in the Etofylline-HSA interaction. The CD spectrum demonstrated some conformational alterations of HSA upon Etofylline addition. Moreover, the distance between tryptophan residue of HSA and Etofylline was calculated by the Forster′s non-radiative energy transfer theory (FRET). The result was in good accordance with the molecular docking outcome.