Study On Chemical Structure Modified Of Natural Product LC And Its Biological Activity Of Rice Blast Fungus

Natural product LC is a kind of acyclic monoterpeniod and has specific bioactivities. As studies show,LC can effect and eliminate epiphyte perfect.However,rice blast is one of the most diseases which effect rice,and chemical methods are the main way to protect from kinds of virus.But rice blast fungus(Pyricularia oryzae(Hebert) Barr.) has better resistance to some common pesticides such as Isoprothiolane.So novel, effective and low residue pesticides and compounds are need to protect rice blast badly.Based on the former results of our laboratory,three main aspects of this paper's research are below.First,comparing and studying the differences between methods of extracting LC by sodium bisulfite and sodium sulfite.Also we have found the differences of methods of extracting LC by sodium bisulfite under both conditions of microwave and tradition. The results showed that the purity of LC can be reached to 96.23%by the condition of sodium bisulfite.The purity of LC can be reached to 96.74%by the condition of sodium sulfite.Also the content of LC can be reached to 97.28%under the condition of microwaves.In comparison,it has several characteristics such as high selection, short periods of operation,little consumption,high rate of recycle and environmental protection under the condition of microwave.Secondly,in order to seek novel,effective and safe compounds,we used the principle of model natural product LC active material and linking inferior structure to design and synthesize thirteen acetal and Schiff base compounds in total.1.Synthesizing four LC acetal compounds,such as LC dimethyl acetal.Identifying their structures by IR,¹H-NMR and elements analysis.2.Synthesizing six LC Schiff base compounds,such as LC anil Schiff base. Identifying their structures by IR.3.LC was reduced into limo-amine by cyclohexfanone oximation of LC and condensation with salicylaldehyde.Then we got salicylaldehyde limo-amine Schiff base compound.Based on that compound,it was mixed into coordination compound with Cu²⁺ and Zn²⁺.Identifying their structures by IR and discussing the coordination of those compounds.Third,all the purposed compounds and natural product LC were operated into the experiment of inhibiting the mycelial growth of Magnaporthe grisea(Hebert) Barr.1.The inhibitory results of natural product LC(500 mg/L and 31.25 mg/L) were 90.31 and 34.8%respectively.EC₅₀ was 50.43 mg/L。2.All the acetal compounds had certain effective inhibitory results.At the concentration of 500 mg/L,LC butanediol acetal had the best inhibitory result in the acetal compounds.It was 80.27%.3.Schiff base compounds also had sound inhibitory results.They were 32.27%～94.88%.At the concentration of 500 mg/L,LC sulfanilamide had the best inhibitory result in the Schiff base compounds.It was 94.88%.At the concentration of 31.25 mg/L,Salicylaldehyde-lemon amine complexes of copper had the best inhibitory result in the Schiffbase compounds.It was 56.91%.4.Results of research showed that natural product LC had better inhibitory results than that of acetal compounds.Relative toxicity index of compounds were 21.45～25.42.Moreover,the inhibitory results of Schiff base compounds were better than that of natural product LC.And it was improved to eliminate rice blast fungus,when Schiffbasses were mixed with metal ions.