Effect of muscle relaxant drug chlorzoxazone on the conformational stability and activity of bovine serum albumin: a spectroscopic and computational study

The commonly used muscle relaxant chlorzoxazone (CZZ) is basic in nature and binds to acidic alpha-1-glycoprotein, affecting the levels of albumins as well as lipoproteins in the body. This can impact the biological half-life of the drug and interfere with its therapeutic requirements. Herein, we have shown the impact of CZZ on the structure of bovine serum albumin (BSA), a transport protein, through various spectroscopic techniques like UV-vis absorption, steady state emission, synchronous fluorescence, and also circular dichroism (CD). Fluorescence results reveal the contribution of hydrogen bonding as well as van der Waal forces for the formation of the complex. Site marker experiments were performed using ibuprofen and indomethacin for site I and site II of BSA, respectively, to understand the competitive binding. UV-visible results show a decrease in absorbance of BSA by the subsequent addition of CZZ and a hypsochromic shift in the spectra. The CD results reveal an increase in BSA's α-helical content in the presence of CZZ, indicating higher folding in the protein's secondary structure. Computational analysis by molecular docking and MD simulations validates the binding of BSA and CZZ and hence, support the experimental findings.