Design, Synthesis, Antibacterial Activity And Mechanism Of Action Of Crotonic Acid Lactones Containing Amide Structure

A series of butenolides compounds containing an amide moiety were designed and synthesized.Evaluate its antibacterial activity against Xanthomonas oryzae pv.oryzae(Xoo)and Xanthomonas oryzae pv.oryzicola(Xoc).The mechanism of action of the highly active target compound has been preliminarily studied.Conclusion as below:Actively splicing the amide structure have a wide range of biological activities with the natural product bunetolides ring.29 butenolides compounds containing an amide moiety were designed and synthesized,and characterized the structure of the target compounds by¹H NMR,¹³C NMR,¹⁹F NMR and HRMS.The turbidity method was used to test the in vivo antibacterial activity of the compound against Xoo and Xoc at 100?g/mL and 50?g/mL.The test results shows that the antibacterial activity of the compound against Xoo was better than against Xoc.Among them,the Ec₅₀value of compound 19 against Xoo was 35.8?g/mL,which were better than bismerthiazol(73.5?g/mL),and equivalent to thiodiazole copper(42.2?g/mL).In vivo experimental tests show that,the protective and curiative activities of compound 19 were48.9%and 40.9%at 100?g/mL,respectively,which were better than bismerthiazol(31.4%and 31.2%),and equivalent to thiodiazole copper(45.5%and 36.1%).The effect of compound 19 on the surface morphology of Xanthomonas oryzae pv.oryzae was observed by scanning electron microscope,and it was found that as the concentration increased,the deformation of the bacteria became more serious.At the same time,enzyme activity experiments showed that the SOD enzyme and CAT enzyme activities treated with compound 19 were significantly enhanced.Preliminary studies on the mechanism of action indicate that the effect of compound 19 on rice bacterial leaf blight in rice plants was closely related to the enhancement of defensive enzyme activity and the up-regulation of oxidative phosphorylation protein.Research on the mechanism of compound 19 against Xanthomonas oryzae pv.oryzae.Observed by scanning electron microscopy,the cell membrane of Xoo treated with compound 19 showed varying degrees of deformation.By comparing the changes in enzyme activity of compound 19,CK,thiodiazole copper and bismerthiazol in different times,the changes of SOD enzyme and CAT enzyme treated with compound 19 are more significant.The mechanism of action studies shown that the protective activity of compound 19 against rice bacterial leaf blight are closely related to improvement of activities defense-related enzymes,and up-regulating proteins involved in oxidative phosphorylation.