Design, synthesis and bactericidal activity of novel acylhydrazine derivatives against Solanum lycopersicum (tomato) bacterial diseases

BACKGROUND Bacterial diseases in plants, especially those caused by Ralstonia solanacearum , pose a significant threat to global agriculture. Traditional chemical pesticides, though effective, have led to growing resistance in pathogens, creating a pressing need for alternative, non-toxic, and environmentally safe antimicrobial agents. Acylhydrazines have emerged as promising candidates due to their broad biological activity. RESULTS The study found that among the novel acylhydrazine derivatives, the compound TSSJ5 exhibited the highest antibacterial activity, with a half-maximal effective concentration (EC 50 ) value of 30.50 mg/L, outperforming the positive control, saisentong, which had an EC 50 of 37.62 mg/L. In vitro and in vivo evaluations confirmed the potent antibacterial efficacy of compound TSSJ5 and its favorable safety profile, particularly for non-target plants such as Solanum lycopersicum . The compound also showed low toxicity to bees. Scanning electron microscopy (SEM) suggested that compound TSSJ5 may disrupt the formation of the bacterial cell wall in R. solanacearum , and density functional theory (DFT) calculations indicated that the activity of compound TSSJ5 surpassed that of saisentong. A three-dimensional quantitative structure–activity relationship (3D-QSAR) model was established to predict the biological activity of similar compounds. CONCLUSION The results of this study demonstrate that compound TSSJ5 is a promising antimicrobial agent with significant antibacterial activity against R. solanacearum and other plant pathogens. Its favorable safety profile for non-target plants and low toxicity to bees make it an ideal candidate for sustainable agricultural applications. These findings contribute to the development of new, environmentally friendly solutions for managing bacterial resistance in plant diseases, advancing the field of plant protection and agricultural chemistry. © 2025 Society of Chemical Industry.