第58屆Intel ISEF中國參賽項目：夾竹桃葉提取物對菜青蟲的殺蟲成分分析及機理研究
盧灣高級中學 高三 楊立青
華師大二附中 高二 顧宇洲
上外浦東附中 高一 王肇欣
學科：植物學
論文對夾竹桃（Nerium indicum Mill.）和白花夾竹桃（Nerium indicum cv.Paihua ）葉的提取物對菜青蟲的作用效果進行了初步研究。結果表明，夾竹桃葉的酒精提取物對菜青蟲具有較強的觸殺和拒食作用。
通過萃取，得到了含有殺蟲成份的乙酸乙酯提取液，經過進一步濃縮干燥，獲得了含有殺蟲活性成分的褐色固體。用甲醇溶解此固體后，采用硅膠薄層層析法進行分離，確定殺蟲活性成分的Rf值為0.75。
通過HPLC分析發(fā)現(xiàn)其中14.311分出峰的組分具有殺蟲活性。用安捷倫的LC/MS分析確定殺蟲活性組分的分子量為598。
論文對夾竹桃葉提取物的殺蟲機理作初步的探討。
Insecticidal Activity of Oleander Leaf Extract against Diamondback Moth and Identification of Its Active Constituent
Plant Sciences
Yang Liqing 18, Luwan Senior High School
Gu Yuzhou 17, No.2 Secondary School attached to East China Normal University
Wang Zhaoxin 16, Pudong Foreign Languages School, SISU
The study is to investigate a common plant in China, oleander, and its effect on diamondback moth (P. Xyloslella). Excessive chem-pesticides spraying leads to pests’ insecticide resistance and human’s health problems. Our study aims at identification, isolation and purification of insecticidal constituent of oleander biological activities of the two species of oleanders existed in Shanghai, Nerium indicum Mill (red flowers) and Nerium indicum cv. Paihua (white flowers), to isolate the active component. The insecticidal activity of ethanol extract from the 2 kinds of oleanders against the moth was tested. Our results indicated only Nerium indicum Mill leaf extract has potent repellent and contact-kill activity. Then, the ethanol extract was separated via various solvents. The active constituent was found dissolved in ethyl acetate. Thin-layer chromatography (silica gel TLC), via a comparison for the 2 species oleanders’ results, shown the component located at zone of Rf=0.75, which was fluorescent under UV. We utilized high performance liquid chromatography (HPLC) to further purify the active component. The LC combined mass spectrometry (LC-MS) determined constituent’s molecular weight is 576D. The nuclear magnetic resonance (NMR) demonstrated the molecular formula is C32H48O9. The mechanisms related to neurotoxic effect were also evaluated via polymerase chain reaction (PCR) of AchE. Finally the research institution evaluated its toxicity to mice, indicated it safe to vertebrate under the efficient pest-killing concentration of 94.2μg/10g. The result shows the active component of oleander leaves has a potential of becoming a novel class of bio-pesticides which is propitious to environmental protection. Future studies will focus on its long-term effect on eco-system, and its killing activity for other pests such as cabbage caterpillars.
