Density functional theoretical study, spectroscopic characterization and molecular docking of the diuretic drug, spironolactone, adsorbed on AuNPs surface and in-vitro studies based on anticancer activity studies against A549 lung cancer cell line

Abstract

In this study, the geometry, intramolecular charge transfer interactions, and harmonic vibrational frequencies of the diuretic drug, Spironolactone (SPL) and SPL adsorbed on gold nanoparticle (SPLA molecule) were investigated with the help of density functional theory method. Both molecules were found to be stabilized by intramolecular hydrogen bonds C7-H37. O27 and C16-H47. O2, as well as intramolecular charge transfer interactions. These interactions were quantitatively confirmed using natural localized molecular orbitals (NLMOs) analysis. The frontier molecular orbital analysis provided a comparative picture of the reactivity, showing a low value of the energy gap, revealing electron transport in the molecule. The most reactive sites of the molecules were predicted by the molecular electrostatic potential map analysis together with the study of local and global reactivity descriptors. FT-IR and Raman spectral analysis confirmed the existence of significant hydrogen bonding, and charge delocalization in the molecules. Molecular docking performed for the biological activity screening of both molecules along with the SERS and MTT assay (in vitro) analysis confirmed their cancer activity. All the comparative results lead to the conclusion that SPLA possess enhanced therapeutic activity than SPL and hence can be used for effective label-free monitoring of cells in-vitro.