Multispectroscopic and molecular docking studies on DNA binding of guaifenesin drug

Abstract

The interaction mechanism of guaifenesin drug; (RS)-3-(2-methoxyphenoxy)propane-1,2-diol; and calf thymus DNA was characterized by multiple spectroscopic and molecular docking approaches. The changes in drug electronic absorption with increasing DNA concentration and also the observed significant quenching of guaifenesin emission in the presence of DNA proved the complex formation between guaifenesin and DNA during the interactions. Both the binding constant and thermodynamic parameters for the interaction have been calculated in 283, 298, and 310 K at pH 7.4. The results $\Delta H^0$ = 17.87 kJ/mol and $\Delta S^0$ = 143.31 J/mol.K confirmed the role of hydrophobic force in the guaifenesin–DNA interaction. Circular dichroism study showed that guaifenesin causes decrease in the negative band of CT-DNA and at the same time the positive band increases which indicated the transition of DNA conformation from B to A. KI quenching experiment specifies that guaifenesin binds to DNA via nonintercalative mode. The competitive studies based on known Hoechst 33258 and methylene blue probes proved the groove binding mode in guaifenesin-DNA adduct. Further, full agreement of molecular docking simulation with the experimental results of binding constant and interaction mode, support high accuracy of the results.

Keywords:

• Guaifenesin
• groove binding
• DNA interaction
• multispectroscopic methods
• molecular docking

Disclosure statement

The authors declare no competing financial interest.