Study On Toxicology Of Coriaria Lactone On Mythimna Separata

Searching leading compound with insecticidal activity from natural products for artificialand modified synthetic compound of higher activity is the focus of new pesticide productionin recent years.There has been few reports on the toxic effect of Coriaria lactone(CL)inChina.In this paper,pesticidal activity of CL,test insect physiological effect,detoxificationsystem and toxic mechanism were deeply studied.The test insect sensitivity degree was alsocomprehensively analyzed.1.In the activity tracing process,we fund that the sesquiterpene lactones in Coriariasinica had antifeeding and killing activity to armyworm(Mythimna separata Walker).Systematic research of toxic symptom,antifeeding activity and toxic effect were conducted toprove the active components and the difference of action mode,and provide accurate theorybasis for grasping the mechanism.The results showed that the toxic symptom of M.separatatreated by Tutin was significant,characterized by insects' slowly crawling,decrease of foodintake,coma,body soften and losing of surface water after recovery.But the effect was notsignificant treated by Coriatin and Coriania.Treated by Tutin and Coriatin in differentproportion(1:3,1:1,3:1),most larvae in the 4th instar went into coma and recovered at 6thinstar.Treated by Tutin and Coriania,insects going into coma at 3rd and 4th instars decreasedand increased at 5th and 6th instars.The effect of sesquiterpene lactones on M.separata's antifeeding is significantlydifferent.For instance,treated by Tutin larvae of all instars had obvious antifeeding activityand it increased with the growing instars.Treated by Coriatin and Coriania,it also hadantifeeding activity but not as obvious as Tutin.Consulting a great number of data,we know that there was few report of the antifeedingactivity of Coriatin and Coriania in China,just what we did in this paper.The contact toxicity of CL manifested the toxic effect of Tutin at 1.0mg/mL was the best.Different proportion of Tutin and Coriatin,Tutin and Coriania had great effect on the foodintaking and cumulative mortality.With the increasing of Coriatin,the effect on food intakingand cumulative mortality became significant.This paper only set cooperative toxicexperiment of 3 different proportion and preliminarily assert that Coriatin and Corianin had synergism effect on the antifeeding and killing activities of Tutin to M.separata.2.Reagent injection and Leaf-sandwiches method were used to test differentphysiological index changes of M.separata.The results showed the protease activity of M.separata was not obviously affected by treatment of Tutin,which made the protein contentcomparatively steady.Coriatin and Coriania influenced the protease secretion of M.separatatissue,interfered the normal metabolism of protease.and caused the accumulation of protein.Carboxylesterase,acetylcholinesterase,S-GST and PPO are important enzyme in insectcatabolism.The enzyme activity affected the role of reagent directly or indirectly.Tutin hadinhibitory effect on Carboxylesterase,which was less significant than those of Coriatin andCoriania.Acetylcholinesterase,as the target enzyme of some reagents,its activity showedvibration curve affected by Tutin and Cariania and was not sensitive to Coriatin.However itneeds further study to prove whether acetylcholinesterase is the target enzyme of Tutin andCariania.S-GST is also an important catabolism enzyme in insect but was not affected by CLat all.3.Due to its special physiological structure,insect has special decomposition,metabolism and detoxification mechanism of the agent that enters the tissue.So this papertried to study the insect detoxification system-blood physiological index.Reference to the testmethods of human blood,liver function and urine index,automatic biochemistry analyzerwere used to test the blood physiological index of M.separata treated by sesquiterpenelactones.The variation rules of index were systematically summarized.The results showed,the alanine transaminase(ALT),γ-glutamyltranspeptidase,total protein,albumin and urea ofthe protein metabolism index were affected by Tutin insignificantly.The aspartateaminotransferase(AST)and globulin were affected by Tutin,Coriatin and Coriania withsignificant effect.The content of alkaline phosphatase,direct bilirubin(DBIL),amylase,creatine kinase,creatine kinase isoenzyme,a-lactate dehydrogenase,lactate dehydrogenase,creatinine,triglyceride and calcium increased.Glucose,total cholesterol,total bilirubin,totalbile acid were not sensitive to Tutin,but Coriatin and Coriania made them decrease.4.The above results showed the effect of CL on physiological function and the responseof M.separata.To prove the difference of response ability,this paper used comprehensiveindexes to evaluate the antifeeding sensitivity,physiological sensitivity and bloodphysiological and biochemical sensitivity of M.separata treated by CL.The response factorsin the physiological and biological process were selected and evaluated.Insect attributeevolution and simulation were studied with different CL treatment.5.We studied the toxic symptom,antifeedant and toxic activity,physiological functionand responsive ability of M.separata treated by 3 CLs,compared the effect of 3 CLs to different physiological index to determine the toxic component and its mechanism,which canhelp to synthesize or modify structure of CL and offer scientific basis for exploring newbotanical pesticide.Test methods of human blood,liver function and urine index,automaticbiochemistry analyzer were firstly used to detect the toxic mechanism of CL on M.separatain our study.The toxicity of tutin and coriation were report in China for the first time.Weexpolred on the principal component analysis and discriminant analysis to select the avalibaleindex to indicate and evaluate the physiological influnce on M.separata treated by CL.Fuzzymathematics was used to propose and build 2 insect physiological index evaluation models.Different lactone components and treated methods were designed to measure the reseanabilityof the 2 models,which quantitatively reflected the different change process of insectphysiological fuction of diferent CLs.