DFT, SERS-concentration and solvent dependent and docking studies of a bioactive benzenesulfonamide derivative

Novel sulfonamide derivatives as a tool to combat methicillin-resistant Staphylococcus aureus

Increasing resistance in Staphylococcus aureus has created a critical need for new drugs, especially those effective against methicillin-resistant strains (methicillin-resistant Staphylococcus aureus [MRSA]). Sulfonamides are a privileged scaffold for the development of novel antistaphylococcal agents. This review covers recent advances in sulfonamides active against MRSA. Based on the substitution patterns of sulfonamide moieties, its derivatives can be tuned for desired properties and biological activity. Contrary to the traditional view, not only N-monosubstituted 4-aminobenzenesulfonamides are effective. Novel sulfonamides have various mechanisms of action, not only 'classical' inhibition of the folate biosynthetic pathway. Some of them can overcome resistance to classical sulfa drugs and cotrimoxazole, are bactericidal and active in vivo. Hybrid compounds with distinct bioactive scaffolds are particularly advantageous.

TD-DFT, DFT, docking, MD simulations, and concentration-dependent SERS investigations of a bioactive trifluoromethyl derivative having human acetylcholinesterase and butyrylcholinesterase in silver colloids

CONTEXT

Various concentrations of (E)-4-methoxy-N'-(2-(trifluoromethyl)benzylidene) benzohydrazide (EMT) adsorbed on colloidal silver nanoparticles were studied using SERS and results were compared to the normal Raman spectrum. DFT calculations were used to validate experimental findings. Theoretically, the structures of the EMT and EMT-Ag6 systems were optimized. The UV-Vis spectral analysis's red shift and lower intensity behavior show that EMT has chemisorbed onto Ag nanoparticles. Charge transfer (CT) from Ag to EMT is highlighted by FMO analysis. The CT interaction in EMT and EMT-Ag6 was further verified by MEP and Mulliken charge analyses. The EMT was adsorbed on Ag nanoparticles with tilted orientation and orientation changes with colloidal concentration, according to SERS spectrum analysis. Docking EMT with 4PQE and 5DYW binding affinities are found to be -9.7 and -8.1 kcal/mol. MD simulations give the competence of 5DYW-EMT and 4PQE-EMT in their intended binding interactions and their ability to establish enduring associations with the protein of interest.

METHODS

DFT was used to optimize the molecular structures of EMT and EMT-Ag6 using B3LYP/6-311++G* (LANL2DZ basis set for Ag). A molecular dynamics simulation study was conducted on the 4PQE-EMT and 5DYW-EMT systems using the Desmond software for 100 ns.

Can DFT Calculations Provide Useful Information for SERS Applications?

Density functional theory (DFT) calculations allow us to reproduce the SERS (surface-enhanced Raman scattering) spectra of molecules adsorbed on nanostructured metal surfaces and extract the most information this spectroscopy is potentially able to provide. The latter point mainly concerns the anchoring mechanism and the bond strength between molecule and metal as well as the structural and electronic modifications of the adsorbed molecule. These findings are of fundamental importance for the application of this spectroscopic technique. This review presents and discusses some SERS-DFT studies carried out in Italy as a collaboration between the universities of Modena and Reggio-Emilia and of Florence, giving an overview of the information that we can extract with a combination of experimental SERS spectra and DFT modeling. In addition, a selection of the most recent studies and advancements on the DFT approach to SERS spectroscopy is reported with commentary.

Adsorption of the drug bempedoic acid over different 2D/3D nanosurfaces and enhancement of Raman activity enabling ultrasensitive detection: First principle analysis

The nanocluster-based drug delivery system is of much importance, now days. This manuscript studies the interaction of pristine/substituted/doped GQDs, fullerene, helicene and CNT with bempedoic acid, which is an effective alternative of statins in the treatment of hypercholesteremia. The adsorption energies are calculated at B3LYP-D3/6-311G+(2d,p) level in order to study the adsorption of bempedoic acid over the surfaces of the nanoclusters incorporating Grimme's dispersion correction. Surface enhanced Raman scattering (SERS), which is a sound approach to vibrational spectroscopy, is used in order to detect bempedoic acid. All the studies signify that bempedoic acid can be detected with these nanoclusters and the negative adsorption energies advocate for the possible use of these nanoclusters as effective drug delivery system in case of bempedoic acid. Adsorption energy of bempedoic acid over helicene was found to be the most negative among the mentioned nanocluster systems, while adsorption on the surface of CNT was found to be the least negative.