Studies On Insecticidal Components Of Corydalis Curviflora

The larvicidal activity of the acetone extracts of 125 plants were screened by Research Center of Biopesticide Technology and Engineering,Northwest A&F University.On this foundation,the higher larvicidal activity of acetone extracts of 12 plants were screened in this paper,Corydalis curviflora was chosen for identification of their insecticidal activity constituents by bioassay-guided fractionation the author focused on the extraction,isolation,identification and studied on insecticidal activity of constituents from Corydalis curviflora.Main results are as follows:The LC₅₀ of Zanthoxylum bungeanum?Corydalis curviflora?Haplophyllum dauricum?Corydalis ophiocarpa Hook.f.et Thomson?Belamcanda chinensis?Lindera obtusiloba against Culex pipiens pallens were 1.086?1.414?1.503?1.851?2.444?2.990 g/L,respectively.The larvicidal activities of the extraction fractions,which were obtained by soaking the powder of C.curviflora with 95%ethanol and then treated with petroleum ether,ethyl acetate,n-butanol and aqueous phase,the 4^th instar larvae of Culex pipiens pallens were tested by the method of liquid immerse with 2.5 g/L samples.The adjusted mortality rate of petroleum ether and ethyl acetate were 92.97%?86.45%,respectively.By bioassay-guided fractionation,twenty compounds were isolated from ethyl acetate and petroleum ether extract of C.curviflora by means of silica gel column chromatography,crystallization and recrystallization.Compounds 1² are novel ones named as Curviflorain I?1?,Curviflorain II?2?respectively.Compounds 3,17 and 18 may be novel compounds,and2D-NMR and HR-MS are being supplemented,and the structure needs to be further determined.The other 13 compounds were identified as:9-oxo-ochotensimine?4?,reticuline?5?,9,10-oxo-ochotensimine?6?,3-heptyl-cyclohexanol?7?,3-monyl-cyclohexanol?8?,oeanolic acid?10?,linoleic acid?11?,stearyl alcohol?12?,Kaempferol?13?,kaempferol-3-O-?-D-glucopyranosyl?14?,rutin?15?,saikogenin A?16?.The larvicidal activities of ten compounds against 4^th instar larvae of C.pipiens pallens and A.albopictus were tested.The results showed that the larvicidal activity of9-oxo-ochotensimine?4?was significantly higher than the other compounds,further results showed that LC₅₀?24 h?of 9-oxo-ochotensimine?4?for 4 instar larvae of C.pipiens pallens was 0.073 g/L.The antifeedant activity of 6 compounds for 4^th instar larvae of M.separata Walks were determined,the antifeedant activity of reticuline?5?against M.separata was significantly higher than the other tested compounds.Antifeedant rate of reticuline?5?for 4^th instar larvae of M.separata were 59.70%?24h?and 62%?25h?,respectively,with the concentration of 0.5g/L.The toxicity of 7 compounds on 3^rd instar larvae of Schizaphis graminum was determined,the corrected mortality was higher than 40%with the concentration of 0.8g/L for 24h.The toxicity of 9-oxo-ochotensimine?4?and reticuline?5?were the best,the corrected mortality was86.67%for 24h.Further results showed that LC₅₀ value of 9-oxo-ochotensimine?4?and reticuline?5?against Schizaphis graminum were 0.295 g/L,0.383 g/L,respectively.All the results indicated that the insecticidal constituents of C.curviflora were structural diversity,such as flavonoids,lignans,phenolic acids,alkaloids,and also vary in insecticidal action modes.9-Oxo-ochotensimine?4?and reticuline?5?showed excellent insecticidal activity which were worth further research,the other activity compounds should be tested further separation.