The project was supported by NSFC.

　　Abstracts: Based on our previous research, two plants belonging to family Meliaceae were selected to study on their chemical constituents and insect antifeeding activity. The methnolic extract of Dysoxylum hannanes showed  antifeeding activity against Pieris rapae L, and 32 compounds were isolated from it. Among the 32 isolated compounds, 20 of them were new and 12 compounds exhibit different antifeeding activity against Pieris rapae L. Six scientific articles were published in this investigation. The methnolic extract of Walsura  yunnanesis showed antifeeding activity against Pieris rapae L different degree, and 22 compounds were isolated from it. Among the 22 isolated compounds, 8 of them were new and 9 tetranortriterpenoids exhibit antifeeding activity against Pieris rapae L at different degree. Two scientific articles were published in this investigation. Besides the Phytochemical investigation on two plants, the chemical transformation from azadirachin to azadirachtinin skeleton were also carried out. During the research, we get essential chemical conditions on the rearrangement. The insect antifeeding activity of two types of compounds was completed, which indicated that two types of compounds possess similar activity.