Study of Interaction of Dextromethorphan Hydrobromide with Deoxyribonucleic Acid by Fluorescence Quenching

Abstract

Interactions with many clinically active therapeutic agents with deoxyribonucleic acid (DNA) are well studied and it expedites deciphering the structure of DNA and to investigate the pathological implication of those molecules in a living organism. The interaction of dextromethorphan hydrobromide (DEX) with calf thymus DNA (ct DNA) was studied employing UV absorption and fluorescence spectroscopic techniques. The binding affinity of DEX to DNA was calculated at different temperatures and the stoichiometry of binding was characterized to be about 1 dextromethorphan molecule per nucleotide. Hypochromic effect was found in the absorption spectra of dextromethorphan, and its wavelength had no shift in the presence of DNA indicating external binding mode of dextromethorphan to DNA. Quenching constants 3532 L/ mol and 12446L/ mol at 298 K and 308 K respectively with correlation co-efficient of 0.974 and 0.976, using SternVolmer equation and the quenching mechanism was found to be dynamic. Fluorescence spectroscopic results showed the quenching of fluorescence intensity of DEX in the presence of DNA, indicating the interaction between DEX and DNA. Based on this, hydrophobic interaction were found to play the dominating role in DEX-DNA binding and those binding forces also indicate the binding site of dextromethorphan to be in the minor groove of DNA.

Transition Metal Chelation Augments the Half-life of Secnidazole: Molecular Docking and Fluorescence Spectroscopic Approaches

“…The fluorescence intensity can be varied as either quenching or de-quenching while interacting with other molecules or ligands [18]. Quelling of the strength of fluorescence property of a fluorophore due to interactions with ligands or drugs is defined as fluorescence quenching, which can be divided as basic two categories like static and dynamic quenching process [19]. The fluorophore and the quencher usually come into contact amid the lifetime of the excited state in dynamic quenching.…”

In vitro Interactions of Secnidazole and Its Iron (II), Copper (II) Complexes with Bovine Serum Albumin by Fluorescence Quenching Method

“…When other molecules like drugs or their metal complexes interact with protein, its intrinsic fluorescence often changes with ligands concentrations (Suryawanshi et al, 2016). Extinguishing of fluorescence strength of a fluorophore due to molecular interactions with other molecules is called fluorescence quenching which can be classified as dynamic or static process (Amin et al, 2016). If the quenching constant is augmented with increasing temperature is known as dynamic quenching whereas in the static quenching it is deducted with the increasing temperature.…”