Novel Cinnamic Acid Derivatives Containing the 1,3,4-Oxadiazole Moiety: Design, Synthesis, Antibacterial Activities, and Mechanisms
Shaobo Wang, Jixiang Chen, Jing Shi, Zhijia Wang, Deyu Hu, Baoan Song
Abstract
There is a lack of effective antibacterial agents against rice bacterial leaf streak and leaf blight. Cinnamic acid derivatives containing the 1,3,4-oxadiazole moiety were synthesized, and their antibacterial activities against Xanthomonas oryzae pv. oryzicola ( Xoc ) and X. oryzae pv. oryzae ( Xoo ) were evaluated. Based on the three-dimensional quantitative structure–activity relationship (3D-QSAR) model, compound 31 with better antibacterial activity against Xoc was designed and synthesized, and the 50% effective concentration (EC 50 ) value was 0.2 mg/L. The curative and protective activities of compound 31 against rice bacterial leaf streak at 100 mg/L were 39.5 and 35.4%, respectively, which were higher than those of thiodiazole copper (28.4 and 20.7%, respectively). The antibacterial activity of compound 31 against rice bacterial leaf streak is closely associated with the activity of related defensive enzymes and the increase in glutathione metabolism.