Chemical reactivity, molecular electrostatic potential, FTIR, NMR, in vitro, and in silico studies of mannopyranoside derivatives: 3-Nitrobenzoylation leads to improve antimicrobial activity

Abstract

This investigation Extensively explored the synthesis and potential therapeutic applications of derivatives derived from methyl α-d-mannopyranoside. It encompasses a wide range of evaluations, including antimicrobial assessments, molecular docking, dynamic simulations, and ADMET analysis. Spectroscopic methods (FTIR, ¹H NMR, ¹³C NMR, mass) were used to confirm the structures of the synthesized mannopyranoside derivatives. This study assessed the antibacterial activity of the strains against a range of both gram-positive and gram-negative bacteria and revealed significant inhibitory effects. In addition, the mannopyranoside derivatives exhibited significant antifungal activity. Additionally, we studied how to improve the thermal, frontier molecular orbital (FMO), and molecular electrostatic potential (MEP) properties of mannopyranoside and its acylated analogs by using density functional theory (DFT). Molecular docking studies provided further evidence of the advantageous antibacterial effects of the mannopyranoside derivatives 3, 6, and 7 against the penicillin-binding protein PBP2a (1VQQ) from the methicillin-resistant binding protein Staphylococcus aureus. The docking results were confirmed via molecular dynamics (MD) simulations, which provided a dynamic view of protein stability. The conformational stability increased in the simulations, and the values of the solvent-accessible surface area (SASA) and radius of gyration (Rg) were found to be consistent and stable. Reduced root mean square fluctuations (RMSFs), facilitated by strong hydrogen bonding interactions, characterize ligand–protein interactions. The toxicological and pharmacokinetic profiles of the molecule were assessed using ADMET analysis. The results showed that the molecule had favorable drug-like features, making it a strong candidate for further development. Overall, these findings indicate that 3-nitobenzoylated mannopyranoside derivatives exhibit considerable potential as therapeutic agents for treating microbial infections.