Novel 2-oxoethylthio-sulfonamide derivatives targeting pyocyanin/staphyloxanthin producing-pathogens: Antibiofilm, DHPS inhibition and gamma radiation effects.

A series of sulfonamide acetamide derivatives 3-14 were synthesized and evaluated for their antibacterial and anti-virulence activities. The target compounds were initially screened in vitro for their antibacterial activity against multidrug-resistant strains of Gram-positive and Gram-negative bacteria. Compounds 9, 10 and 13 showed significant antibacterial activity with bactericidal effects, compared to the standard antibiotics, ampicillin and sulfamethoxazole. These derivatives were then further tested for their antibiofilm activity against biofilm-forming S. aureus and P. aeruginosa. At sub-MIC levels, these compounds disrupted over 80 % of the biofilm structures formed by both bacteria. SEM analysis confirmed the disruption of the biofilm matrix in the presence of these derivatives. To assess anti-virulence activity, compounds 9, 10 and 13 demonstrated potent hemolysin inhibition activity, ranging from 83.15 % to 87.77 % for S. aureus and 84.01 % to 88.82 % for P. aeruginosa. They also significantly reduced the production of staphyloxanthin in S. aureus and pyocyanin in P. aeruginosa, confirming their anti-virulence potential. Furthermore, compounds 9, 10 and 13 showed strong inhibitory activity against dihydropteroate synthase (DHPS) enzyme and were effectively sterilized with a gamma radiation dose of 7.0 kGy without affecting their physicochemical properties. Molecular docking studies confirmed that these compounds exhibit favorable binding interactions within the active site of DHPS. These findings reveal the potential of the 2-oxoethylthio sulfonamide scaffold to produce compounds with combined antibacterial and anti-virulence properties.