Spectroscopic characterization, antimicrobial activity, DFT computation and docking studies of sulfonamide Schiff bases

• Sulfonamide Schiff bases of 2-(hydroxyl) naphthaldehyde.
• Spectroscopic characterization and single crystal X-ray structure.
• DFT computation of the Schiff bases for energy minimized structure.
• Antibacterial study against Gram-positive and Gram-negative bacteria and cytotoxicity.
• Molecular docking studies of the Schiff bases with DHPS to support experimental results.

Schiff bases synthesised from the condensation of 2-(hydroxy)naphthaldehyde and sulfonamides (sufathiazole (STZ), sulfapyridine (SPY), sulfadiazine (SDZ), sulfamerazine (SMZ) and sulfaguanidine (SGN)) are characterized by different spectroscopic data (FTIR, UV–Vis, Mass, NMR) and two of them, (E)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-N-(thiazol-2-yl)benzenesulfonamide (1a) and (E)-N-(diaminomethylene)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzenesulfonamide (1e) have been confirmed by single crystal X-ray structure determination. Antimicrobial activities of the Schiff bases have been evaluated against certified and resistant Gram positive (Staphylococcusaureus, Enterococcus facelis) and Gram negative (Streptococcuspyogenes, Salmonellatyphi, Shigelladysenteriae, Shigella flexneri, Klebsiella pneumonia) pathogens. Performance of Schiff base against the resistant pathogens are better than standard stain and MIC data lie 32–128 μg/ml while parent sulfonamides are effectively inactive (MIC >512 μg/ml). The DFT optimized structures of the Schiff bases have been used to accomplish molecular docking studies with DHPS (dihydropteroate synthase) protein structure (downloaded from Protein Data Bank) to establish the most preferred mode of interaction. ADMET filtration, Cytotoxicity (MTT assay) and haemolysis assay have been examined for evaluation of druglike character.

Sulfonamide Schiff bases of 2-hydroxynaphthaldehyde have been characterised and tested for antimicrobial activity against Gram positive and Gram negative bacteria (MIC data lie 32 – 128 μg/ml). These are more effective than their parent sulfonamides (MIC of sulfonamides >512 μg/ml). Docking studies against DHPS protein also support the experimental observation. ADMET filtration, Cytotoxicity and haemolysis assay have been examined for evaluation of druglikeness character.Figure optionsDownload as PowerPoint slide