The interaction between citronellol and bovine serum albumin: Spectroscopic, computational and thermal imaging studies

• Molecular mechanism was revealed for citronellol and tourmaline of physiotherapy. • Citronellol bound to site i and slightly changed the conformation of BSA. • Hydrogen bonds and van der waals forces played a major role in the binding. • Citronellol and tourmaline powder increased the thermal response of BSA. Citronellol (Cit), a typical component of rose essential oil, has a variety of physiological activities and is widely used in physiotherapy with tourmaline powder (TP). But the reaction mechanism with biomolecules was not concerned. Therefore, the action mechanism of Cit/TP to bovine serum albumin (BSA) was studied through spectroscopic, docking, dynamic simulation and thermal imaging methods. The results suggested that Cit and BSA could bind at site I chiefly under the driving forces of hydrogen bonds and Van der Waals forces, and the endogenous fluorescence quenching mode of BSA was static. Synchronous, three-dimensional fluorescence spectra, UV–vis, FT-IR reflected Cit could affect the microenvironment near tryptophan and promote the aggregation of the protein structure to change the conformation of BSA. The molecular dynamics (MD) simulation confirmed the conformational change of BSA after ligand binding. Besides, the analysis showed that the existence of TP could improve the affinity of Cit-BSA binding. Infrared thermal images proved that Cit and/or TP could improve the radiation temperature of BSA system. In brief, Cit could spontaneously bind to BSA and change the protein conformation, and the presence of TP would affect the binding mode of Cit-BSA. These findings will be beneficial to further research of Cit and TP in physiotherapy.