Phenylvinylsulfonate-Anchored Azetidin-2-ones as Potent Antibacterial Agents: ROS-Mediated Mechanism, Selective...

The rise of multidrug-resistant pathogens, including MRSA, underscores the urgent need for novel antibacterial agents with minimum resistance potential and enhanced potency. Herein, we report the design and synthesis of novel phenylvinylsulfonate-anchored azetidin-2-ones 8a-h & 9i-j via the reaction of (E)-2-phenylethene-1-sulfonyl chloride with differently substituted 3-hydroxy azetidin-2-ones. Structural confirmation was achieved by ¹H NMR, ¹³C NMR, HRMS, and stereochemical elucidation based on the J-coupling values of C3-H and C4-H. Among the series, compound 9j exhibited the most potent antibacterial activity against MRSA (MIC: 7.5 μg/mL), outperforming Tetracycline. Mechanistic investigation using ROS quantification (DCFH-DA assay) revealed markedly elevated intracellular ROS (OD: 71,467), suggesting a possible ROS-mediated bacterial damage mechanism. Molecular docking interactions further supported the strong binding of 9j to penicillin-binding protein 2a (PBP2a, PDB: 1VQQ) with a docking score of -6.68 kcal/mol. Additionally, 9j exhibited selective cytotoxicity toward HCT-116 colon cancer cells with an IC₅₀ value of 9.82 ± 0.21 μM while maintaining moderate viability (~52%) in NIH-3T3 normal fibroblast cells. Collectively, these findings highlight phenylvinylsulfonate-anchored azetidin-2-ones as promising antibacterial agents with a ROS-driven mechanism and supplementary selective cytotoxic potential.