Synthesis of two new naphthalene-containing compounds and their bindings to human serum albumin

Two naphthalene-containing compounds, 4-hydroxy-6,7-dimethoxy-1-(4-(trifluoromethyl)phenyl)-2-naphthoic acid (A) and 4-hydroxy-6,7-dimethoxy-1-phenyl-2-naphthoic acid (B), were prepared by several steps. Their bindings to human serum albumin (HSA) were studied by ultraviolet–visible (UV–vis) absorption, fluorescence, synchronous fluorescence, three-dimensional fluorescence, circular dichroism (CD) spectroscopies and molecular docking. The crystal data of these compounds show the structure of the compounds. The results show that the mechanism of the interaction between compound A and HSA is mixed-quenching (both dynamic and static quenching), while that of compound B and HSA is static quenching. The number of binding sites, binding constants and binding distance (r) were obtained. The interaction processes are spontaneous. A mainly interacts with HSA through typical hydrophobic interaction, and B binds to HSA mainly by the hydrogen bonds and van der Waals forces. The conformation of HSA changes slightly after the addition of the compounds. Besides, molecular docking method was used to study the interaction details between the compounds and HSA. This is helpful to understand the absorption and metabolism of these two compounds in the body, and provides a basis for designing naphthalene-containing drugs. Communicated by Ramaswamy H. Sarma