Extraction, Separation And Effect Patterns Of The Activie Ingredients In Portulaca Oleracea L Extracts Against Aphis Gossypii Glover

Recently more attention has been paid on products of natural plants whichplay a important role on encouraging sdudies of recent to organic synstheticinsecticides which is a serious threat to the environment such as resistance,residue and resurgence. In order to develop new ways and new natural productsfor controlling the vegetable pests and providing possible temples for thesynthetic of new "bioregulators", a primary studies on extration, separation andbioassays of the active ingredient in Portulaca oleracea L extracts againstcotton aphis were made in this paperPortulaca oleracea L belongs to Portulacaceae and is one of Chinesetraditional herbal medicine plants. The wild P. oleracea has very strongbioactivity against fungi and bacteria and had been used to cure many diseasein clinic, but only a few researches focus on P. oleracea against the vegetablepests and especially are not systemic sdudies at the present time. RegardingAphis gossypii Glover as target pest , both the technic of distillment andseparation of the bioactive materials from the plant and the action way of thosebioactive materials to the Aphis gossypii Glover were studied systemically inpresent paper. The study provides the clue and theoretical basis for thedevelopment and utilization of this insecticidal plant in the future. The mainresults are as follows:1.Extracts of P. oleracea have a high contact toxicity to Aphis gossypiiGlover.(1) The contact toxicity to Aphis gossypii Glover of the extracts from thedried P. oleracea are higher than that from the fresh P. oleracea at the sameconcentration. Dried and fresh P. oleracea were extracted by cold-dippingmethod with nine different solvents and the results indicated that acetoneextract from the dried plant showed the highest contact toxicity with 1.88mg/mL (dried powder) of LC50 afer 48h; Ethanol extract from the fresh plant hadthe highest contact toxicity with 8.80mg /mL (fresh tissue) of LC50. (2)The extract distilled from dried P. oleracea by warm-dippingmethod with methanol has the highest contact toxicity(LC50=1.19mg/mL)among all the extracts. 2. Extracts of P. oleracea has a high antifeedant toxicity to Aphisgossypii Glover. (1)The antifeedant toxicity to Aphis gossypii Glover of the extractsfrom the dried P. oleracea are higher than that from the fresh P. oleracea at thesame concentration. dried and fresh P. oleracea were extracted by cold-dippingmethod with nine different solvents and the results indicated that petroleumether extract from the dried plant had antifeeding rate of 81.02% at theconcentration of 25mg/mL. Otherwise , petroleum ether extract from the freshplant only had antifeeding rate of 70.56% at the same concentration. (2)The extract distilled from dried P. oleracea by soxlet's extractionmethod with petroleum ether has the highest antifeedant toxicity(AFC50=3.84mg/mL) among all the extracts. 3.The extract distilled from P. oleracea by warm-dipping method withmethanol had been crudely separated .The results indicated that ethyl acetateextract showed the highest contact toxicity in the four different extracts.Among the three concentration of 20,10 and 5mg/mL,ethyl acetate extract allshowed the highest contact toxicity to Aphis gossypii Glover and it's adjustedmortality rate was 98.21%.Then the Trichloromethane extract and water extract.Petroleum ether extract had the lowest contact toxicity. 4.The extract distilled from P. oleracea by soxlet's extraction methodwith Petroleum ether had been rudely separated .The results indicated thatBenzene extract showed the highest antifeedant toxicity in the four differentextracts. Among the three concentration of 5000, 2500 and 1250μg/mL,Benzene extract all showed the highest antifeedant toxicity to Aphis gossypii...