Exploration of semi-carbazone derivatives as promising agents against cholera: Insights from spectroscopic analysis, reactivity studies (ELF, HOMO-LUMO, NBO), solvation effects, and molecular docking investigations

This study is aimed at evaluating the impact of solvation on the structural, spectroscopy (UV, NMR, FT-IR), reactivity, bonding interactions, and the drug potential of Pyridine 4-Carbaldehyde Semi-carbazone (PCS) against the disease (cholera) causing protein in the Gram-negative bacterium; Vibrio cholerae. Notably, the study was carried out using both experimental and theoretical calculations based on density functional theory (DFT) at the GD3B/B3LYP/6-311G++(2D,2P) level of theory along with molecular docking. Results from the UV- spectrum showed very fair absorption levels across the different solvents used, with theoretical peaks at 463 nm, 467 nm, 470 nm and 468 nm for PCS_DMSO, PCS_ETOH, PCS_H2O and PCS_MEOH, respectively. The study reveals discrepancies between experimental and theoretical H-1 NMR shifts. However, theoretical C-13 NMR shifts show minute differences. RDG analysis reveals steric repulsions in the pyridine ring. Whereas, the investigation of electronic properties reveal that the decreasing order of PCS_DMSO (3.668 eV) > PCS_H2O (3.206 eV) > PCS_MEOH (3.202 eV) > PCS_ETOH (0.312 eV). The results of docking showed that PCS had binding affinities of -5.0 Kcal/mol with protein 7P3R and -5.4 Kcal/mol with protein 1XTC which happen to be much lesser than -10.2 Kcal/mol formed between erythromycin and 7P3R. However, erythromycin formed a non-feasible bonding interactions with 1XTC with biding affinity of 18.0 Kcal/mol. Results of the MD simulation showed that PCS-MEOH had a higher energy value than PCS-DMSO, PCS-ETOH, and PCS-H2, indicating that it can interact with other substances more effectively, disperse more quickly. These results from the various studied objectives, however, suggest Pyridine 4-Carbaldehyde Semi-carbazone to be a lead compound for tackling the incidence, distribution and prevalence of cholera.