引种印楝国产种子的印楝素含量及杀虫活性初步研究

应用高效液相色谱法（HPLC）定量分析结果表明,从海南省种植的印楝树（Azodirochta indica A.Juss)上收获的种子中印楝素（Azadirachtin)含量为0．48％,甲醇提取物获得率为16．395,其中含印楝素2．95,国产印楝种子提取物对亚洲玉米螟（Ostrinia furnccalis)和小菜蛾（Ptutella xylostella)幼虫均有强烈的抑制生长发育作用活性,提取物馏分F3－5（含印楝素0．883％）500ppm饲喂亚洲玉米螟4－5龄幼虫造成100％畸形死亡和变成“永久性幼虫”,113ppm时也有显著效果,2％处理小菜蛾四龄幼虫也使之100％畸形死亡,试验还发现不含印楝素的其它馏分对上两种害虫也有不同程度的作用效果,值得进一步研究。

PRELIMINARY STUDIES ON AZADIRACHTIN CONTENT AND INSECTICIDALACTIVITY OF THE SEEDS FROM THE INTRODUCED NEEM TREES Azadirachtaindica A. Juss PLANTED IN CHINA

With High Performence Liquid Chromatograph (HPLC), a quantative analysis of azadirachtin of neem seeds collected from neem trees that were introduced from Togo, Africa, now successfully cultivated in Wannin county, Hainan Province, China, as well as the test of insecticidal activity of the seed extracts have been conducted in the laboratory. The results showed that the air-dried seeds contained azadirachtin up to 0. 48%. The methanol extract with a recovery rate of 16. 39% from the neem seeds contained azadirachtin at 2. 94%. F3-5, a fraction of the methanol extract containing azadirachtin at 0. 883% was significantly effective against the 4 - 5th instar larvae of Asiatic corn borer,Ostrixia furnocalis when administered at a concentration of 113 ppm mixed with an artifical diet,and all the larvae developed malformation and died or became so call "permanent larvae" when treated at a concentration of 500 ppm. Arter eating or coming in contact with leaves trteated with 2%of F3-5, all the 4th instar larvae of the diamondback moth, Plutella xylostella were inhibited in their growth and development, malformation and death following. Besides the F3-5, other fractions of the methanol extract containing no azadirachtin e. g. F1-2, F6-15 and Fm, also showed similar bioactivity against the two insect pests, this is worthy of futher studies.