Biological Activity Research Of Hydronopic Derivatives To Culex Pipiens Pallens

As an insect vector,mosquitoes spread more than 100 kinds of diseases,such as malaria,dengue fever,yellow fever,lymphatic filariasis,Zika virus disease and so on.These mosquito-borne diseases led to about one million people death each year.Currently,mosquito control was mainly depended on the application of chemical insecticides.However,these traditional insecticides had already unable to meet the demand of future mosquito control,because of the increasing resistance of mosquitoes to insecticides,environmental pollution,and pesticide residue.Therefore,the developments of novel insecticides and repellent were of great importance.Previous studies carried out by our group found that hydronopol derivatives had promising insecticidal activity and repellency against mosquitoes.Therefore,in this research,the insecticidal activity and repellency of a series of hydronopol derivatives which derived from natural occurring compound?-pinene were evaluated,and tested with electroantennogram?EAG?in order to find out some derivatives with excellent insecticidal activity and repellency,as well as to provide theoretical guidance for the research and development of novel insecticides and repellents.In the study twenty-five hydronopol derivatives?including acetals,amides,quaternary ammonium salt?were used as tested compounds,and the larvae,pupa and adult of Culex pipiens pallens were used as tested insect.The toxicity of the tested compounds to the larvae and pupa of Culex pipiens pallens were tested via immersion method.The fumigation effects of the tested compounds to the adult of Culex pipiens pallens were tested by fumigation method.The repellency of the tested compounds to the adult of Culex pipiens pallens were tested through mosquito repellent.The electroantennogram?EAG?responses of the antenna of Culex pipiens pallensto the tested compoundswere recorded by electroantennographic detector.The main research results were:1)The results of toxicity evaluation of twenty-five hydronopol derivatives showed that nine derivatives with high lethality were selected.The toxicity of these derivatives was decreased with the growth of larvae,the LC₅₀ of the derivatives against the first instar was the smallest and the LC₅₀ of the derivatives against the pupa was the biggest.After 24 h,four derivatives hydronopic aldehyde glycol acetal?S2a?,hydronopic 1,2-propanediol acetal?S2c?,hydrogenated nopaldehyde 1,3-propanediol acetal?S2b?exhibited good toxicity against the 4th instar larvae,Their LC₅₀0 were 80.056,90.112,103.610 and 111.600mg/L,respectively.2)The results of fumigation evaluation of twenty-five hydronopol derivatives showed that at the concentration of 12.8%,seven derivatives?N-o-hydroxyphenyl hydronopic amide?X4i?,N-m-nitrophenyl?X4a?,N-methyl hydronopic amide?X4a?,N-phenylhydronopic amide?X4e?,hydronopic dehyde ethylene glycol acetal?S2a?,hydronopic aldehyde?S2c?,5-propanediol acetal?S2c??exhibited good fumigation activity against adult of Culex pipiens pallens,Their KT₅₀ were less than 10min.Meanwhile,four compounds hydronopic dehyde ethylene glycol acetal?S2a?,hydrogenated nopaldehyde1,3-propanediol acetal?S2c?,hydrogenated nopaldehyde 1,2-propanediol acetal?S2b?,N-methylated hydronopic amide?X4a?exhibited better fumigation activity,their KT₅₀were less than 10minat the concentration of 12.8%,and their LC₅₀were less than 0.5%after 24h.3)The repellency evaluation of twenty-five hydronopol derivatives showed that six derivatives?hydronopic aldehyde acetal?S2a?,hydronopic aldehyde 1,2-propanediol acetal?S2b?,N-i-propyl hydronopic amide?X4d?,hydronopic tri-ethyl ammonium iodide?L4f?,N-hydrogenated nopipyridine ammonium bromide?N4a?,hydronopic tri-n-butyl amine ammonium iodide?L4g?exhibited good repellency against adult of Culex pipiens pallens,the repelling rates of these compounds were greater than 50%.4?The EAG analysis showed that at the concentration of 1000 mg/L,seven derivatives?hydronopic ethylene glycol acetal?S2a?,hydronopic aldehyde 1,3?X4b?,N-n-propyl hydronopic amide?X4c?,N-m-nitrophenyl hydronopic amide?X4j?,hydronopic tri-methyl ammonium chloride?L4a?,N-hydronopic pyridine ammonium bromide?N4a??had significantly induced the responses of the antenna of Culex pipiens pallens.The relative percentages of response to these compounds were all greater than 250.In conclusion,four derivatives of hydronopol(hydronopic aldehyde glycol acetal?S2a?,hydronopic 1,3-propanediol acetal?S2b?,hydronopic 1,2-propanediol acetal?S2c?,hydronopic tri-n-butylamine iodination?L4g?which exhibited good insecticidal activity and repellency were selected in this research.In addition,hydronopic aldehyde glycol acetal?S2a?showed excellent insecticidal activity or repellency against the larvae,pupa and adult of Culex pipiens pallens.Compound S2a was worth further development and utilization.This research might provide theoretical reference to the future study on the insecticidal activity and repellency evaluation of hydronopol derivatives.Meanwhile,this research plays a positive role in promoting the research and development of novel insecticides and repellents.