Discovery of novel bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties as potential antibacterial agents

On the basis of the active substructure combination principle, 24 novel synthesis of novel bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties as potential antibacterial agents were designed and synthesized. The bioactivity assay results showed that many compounds had significant in vitro inhibitory effects against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas citri pv. citri (Xac). Notably, compound 4b had the best in vitro antibacterial activity against Xoo at an half-maximal effective concentration value of 11.4 μg/mL, which was superior to those of thiodiazole copper (TDC) and bismerthiazol (BMT). Compared with TDC and BMT, compound 4b was more effective in vivo controlling rice bacterial leaf blight with curative and protection activities of 42.5% and 40.3%, respectively. In addition, compound 4b can influence biofilm formation, inhibit extracellular polysaccharide production, and ultimately reduce the pathogenicity of Xoo. All the results indicated that bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties can be used for the development of small-molecule pesticides with high antibacterial activity.