Studies On Bio-Activities Of Plant Extracts Against Lipaphis Erysimi Kaltenbach And Chenopodium Album L.Active Components Extraction

In this dissertation,Lipaphis erysimi Kaltenbach was used as the test insect to screen the bioactivity activity of ethanol extracts from five different plants,and Chenopodium album L.,a plant with high bioactivity of radish aphid,was used as the research object to screen the optimum technological conditions for extracting its active ingredients,and to preliminarily isolate and trace its active ingredients.Screening the optimal process conditions for extracting bioactive components.Through screening,it was found that ethanol extracts from five species of plants,Artemisia annua L.?Chenopodium album L.?Setaria viridis?L.?Beauv.?Oxalis corniculata L.?Nymphoides peltatum?Gmel.?O.Kuntze,all showed a certain degree of comprehensive toxicity to aphids.Among them,plant extracts from Artemisia annua and Chenopodium annua showed the highest bioactivity activity.The result showed that extracts from Artemisia annua L.and chenopodium showed high activity against aphid.The contact-corrected mortality of five different plant ethanol extracts against aphids was in the order from high to low,were:Artemisia annua L.>Chenopodium album L.>Setaria viridis?L.?Beauv.>Oxalis corniculata L.>Nymphoides peltatum?Gmel.?O.Kuntze,The corrected mortality of ethanol extracts of Artemisia annua L.and Chenopodium album L.at 72 h at 100 mg/mL reached 70.36%and 70.31%,respectively.The results showed that ethanol extracts of five plants at different concentrations had comprehensive toxic effects on aphids at 48 h and 72 h.In the above treatment,the lowest LC₅₀ value was Chenopodium,40.07 mg/L,corresponding to 95%confidence interval of 34.09-47.08 mg/L,followed by Artemisia annua,with LC₅₀value of 45.62 mg/L,corresponding to 95%confidence interval of 30.78-67.62 mg/L.The order of LC₅₀ values from low to high was:Chenopodium album L.<Artemisia annua L.<Setaria viridis?L.?Beauv.<Oxalis corniculata L.<Nymphoides peltatum?Gmel.?O.Kuntze.Chenopodium was extracted with 95%ethanol by three methods:soakage extraction method,ultrasonic extraction method and Soxhlet extraction method.It was found that the ultrasonic extraction method was the best extraction method for Chenopodium,and the extraction rate was 16.14%.The comprehensive toxicity of four extracts with ethanol,petroleum ether,water and acetone as solvents to aphids was as follows:petroleum ether>ethanol>acetone>water extract.The corrected contact mortality of extracts with ethanol,petroleum ether,water and acetone as solvents to aphids was as follows.The plant Chenopodium extract with petroleum ether as the extraction solvent had the highest acaricidal activity,and the corrected mortality rate at 72 h at 100 mg/mL was 82.53%.It was found that the extracts of Chenopodium with petroleum ether and ethanol as solvent showed extremely high contact toxicity.The corrected mortality at 72 h at150 mg/mL was 97.69%and 93.82%,respectively.The corresponding LC50 values were 22.43 mg/mL and 34.70 mg/mL,respectively.Moreover,it was found that the extract of Chenopodium with petroleum ether as solvent showed a certain antifeedant effect on Lipaphis erysimi,and the average refusal rate at 72 h at 150 mg/mL was73.33%.The anti-feeding medium concentration AFC50=61.73 mg/mL,corresponding to the 95%confidence interval of 43.04⁸8.55 mg/mL.With the increase of the concentration of the Chenopodium extract,the mortality rate of the mites and the average refusal rate increased.The ethanol extract was subjected to preliminary extraction and separation,and petroleum ether phase,chloroform phase,ethyl acetate phase,butyl alcohol phase and water phase were obtained in sequence.The corresponding extraction rate was:n-butyl alcohol phase>ethyl acetate phase>chloroform phase>petroleum ether phase>water phase.The extracts of each phase were tested for comprehensive poisoning.It can be seen that the highest insecticidal activity is the petroleum ether phase,and the butyl alcohol phase also exhibits higher insecticidal activity.The corresponding mortality for 72 h at 50 mg/mL insecticidal correction was:petroleum ether phase>n-butyl alcohol phase>ethyl acetate phase>chloroform phase>water phase.It was found that petroleum ether phase had the highest insecticidal activity and corrected mortality was 78.82%.At the same time,n-butanol phase also showed high insecticidal activity,and corrected mortality was 71.99%.In order to further study the active constituents of Chenopodium,the plant extracts of petroleum ether phase were subjected to column chromatography to obtain19 fractions,which were detected by thin layer chromatography?TLC?and combined into 7 fractions for killing activity test.It can be seen that the petroleum ether phase extract column chromatography No.?and No.?fractions exhibit high acaricidal activity.The corrected mortality after 72 h at 50 mg/mL was 62.28%and 60.70%respectively.