Isolation And Identification Of Aphidicidal Active Components From Moso Bamboo Leaf Extract

Excessive and unscientific utilization of chemical pesticides threatens the quality of crop products and the safety of agricultural ecological environment,seriously.Searching for insecticidal active ingredients from plants is an important research content in developing environment-friendly botanical pesticides,which is of great significance for reducing and replacing chemical pesticides.Previous studies by our research team found that the Phyllostachys heterocycla leaf extract had good biological activities such as insecticidal activity and bacteriostatic activity,but there were few reports about the active components of P.heterocycla leaf extract against aphids.On the basis of optimizing the preparation method of P.heterocycla leaf extract,the aphidicidal active components in P.heterocycla leaf extract were isolated and identified by biological activity tracing method,and the effects of aphidicidal active components on the 3 neuro-enzymes of M.persicae were evaluated combined with the contact symptoms of M.persicae.The main research results were as follows:1.optimization of preparation method of P.heterocycla leaf extract and determination of its aphidicidal activity.The effects of extraction time,extraction temperature,extraction times and ratio of material to liquid to the extraction yield of P.heterocycla leaves were investigated by orthogonal design test.The preparation method of P.heterocycla.leaf extract was as follows: the extraction solvent was 75% ethanol,the extraction temperature was 75℃,the ratio of raw material to 75% alcohol was 15:1,three times and 4 each time,extraction yield was 9.70±0.31%.At the treatment concentration of 10g/L,the corrected mortality rates of the P.heterocycla.leaf extract to M.persicae were 52.26±1.93%,57.32±1.29% and 67.27±1.48% after treated 24h,48h and 72h,respectively.2.Isolation and identification of main aphidicidal active components from P.heterocycla leaf extract.The aphidicial activity of different polar solvent extracts from P.heterocycla leaf extract showed that the corrected mortality rates of petroleum ether extract,chloroform extract,ethyl acetate extract,n-butanol extract and aqueous extract to M.persicae were 96.21±0.76%,77.03±1.20%,48.00±1.59%,48.20±1.77% and 48.74±0.65% after treated 72h,respectively.At the treatment concentration of 10g/L.Among 5 polar solvent extracts,petroleum ether extract had the best aphidicidal activity,and the LC50 values of contact activity to M.persicae were 4.20g/L,3.60g/L and 3.30g/L after treated 24h,48h and 72h,respectively.11 fractions were separated from petroleum ether extract by silica gel column chromatography.At the treatment concentration of 4g/L,the corrected mortality rates of Fr₁～Fr₁1 fractions to M.persicae were 51.53%～91.12% after treated 24h,51.86%～93.51% after treated 48 h and 55.16%～96.08% after treated 72h.The corrected mortality rates of Fr₁ fraction to M.persicae were 91.12±1.20%,93.51±1.38% and 96.08±0.08% after treated 24h,48h and 72h,which had higher aphidicidal activity than other separated fractions,significantly（P<0.05）.The Fr₁ fraction was separated by gel column chromatography to obtain 18 fractions.At the treatment concentration of 1g/L,the corrected mortality rates of Fr₁.1～Fr₁.18 fractions to M.persicae were 1.78%～59.11% after treated 24 h,3.09%～67.24% after treated 48h and 6.79%～72.74% after treated 72h.Among them,The aphidicidal activity of Fr₁.13 was higher than other fractions,significantly（P<0.05）,and the corrected mortality rates to M.persicae were 59.11±1.43%,67.24±1.20% and 72.74±0.60%,after treated 24h,48h and 72h,respectively.3 compounds were isolated from Fr₁.13 by TLC,which were identified as 2,5-bis（3,7-dimethyloctyloxy）terephthalaldehyde,pallason C and erucamide based on the data of NMR and LC-MS.The bioassay results showed that the LC50 values of 2,5-bis（3,7-dimethyloctyloxy）terephthalaldehyde,pallason c and erucamide were 0.60g/L,0.34g/L and 1.47g/L after treated 24h;0.40g/L,0.23g/L and 1.14g/L after 48 h;0.32g/L,0.18g/L and 0.86g/L after treated 72 h,respectively.Pallason C had the best contact activity against M.persicae,whose contact activity against M.persicae was similar to matrine（LC50 value was 0.17g/L,after treated 72h）.3.The effect of pallason C on the activity of 3 kind enzymes related with M.persicae neuro-systemCombined with the contact symptoms of M.persicae treated with pallason c,the effects of pallason C on the activities of 3 kind enzymes related with M.persicae neuro-system were evaluated,systematically.When the treatment time is 24 hours,at the treatment concentration of 0.1g/L,0.2g/L and 0.3g/L,the inhibition rates to Ach E were 8.27±0.11%,14.64±0.05% and 19.48±0.11%;the inhibition rates to Na+-K+-ATPase were 14.47±0.09%,35.90±0.12% and 48.11±0.08%;the inhibition rates to Ca²⁺-Mg²⁺-ATPase were10.37±0.13%,18.02±0.05% and 18.90±0.05%,respectively.Combined with the contact symptoms to M.persicae,the mechanism of action of pallason C may be related to Na⁺-K⁺-ATPase.