Exploring the interaction of Azure dyes with t-RNA by hybrid spectroscopic and computational approaches and its applications toward human lung cancer cell line.

In the present study, in depth characterization of binding aspects of Azure A (AZA) and Azure B (AZB) with transfer Ribonucleic acid (t-RNA) from Escherichia coli (E.coli) is investigated using spectroscopic techniques. The absorbance and fluorescence properties of these dyes have been remarkably changed upon binding with t-RNA. Significant changes in the absorption maxima of the dyes evidence the t-RNA induced metachromasy and the binding clearly revealed the high affinity of AZA and AZB to t-RNA. Strong emission polarization of the bound dyes and strong energy transfer from the guanine base pairs of t-RNA suggested intercalative binding interaction. The stoichiometry of AZA and AZB with t-RNA complexes are determined by the Benesi-Hildebrand plot from emission data. The negative values of free energy change indicated the involvement of hydrophobic forces and noncovalent interactions in the complexation of both the dyes with t-RNA. The 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay in A-549 human lung cancer cell lines reveals that binding of t-RNA reduces the toxicity of AZA and AZB. The utility of the present work explores the potential binding applicability of these dyes to t-RNA for their development as effective therapeutic agents and its target at molecular level for the treatment of diseases like cancer.