Synthesis of a Novel Hydrazone Derivative and Biophysical Studies of Its Interactions with Bovine Serum Albumin by Spectroscopic, Electrochemical, and Molecular Docking Methods

Hydrazone derivatives possess potential antitumor activities based on modulation of the iron metabolism in cancer cell. A novel hydrazone, N′-(2,4-dimethoxybenzylidene)-2-hydroxybenzohydrazide (DBH), has been synthesized and characterized, which is an analogue of 311 possessing potent anticancer activity. The interactions between DBH and bovine serum albumin (BSA) have been investigated systematically by fluorescence, molecular docking, circular dichroism (CD), UV−vis absorption, and electrochemical impedance spectroscopy (EIS) methods under physiological conditions. The fluorescence quenching observed is attributed to the formation of a complex between BSA and DBH, and the reverse temperature effect of the fluorescence quenching has been found and discussed. The primary binding pattern is determined by hydrophobic interaction occurring in Sudlow's site I of BSA. DBH could slightly change the secondary structure and induce unfolding of the polypeptides of protein. An average binding distance of ∼4.0 nm has been determined on the basis of the Förster resonance energy theory (FRET). The effects of iron on the system of DBH−BSA have also been investigated. It is found that iron could compete against BSA to bind DBH. All of these results are supported by a docking study using a BSA crystal model. It is shown that DBH can efficiently bind with BSA and be transported to the focuses needed. Subsequent antitumor test and detailed anticancer mechanism are undergoing in our lab.