中文摘要：

【目的】探明苍耳Xanthium sibiricum活性物质——环氧苍耳素Ⅰ对菜青虫的作用机理。【方法】采用饲喂法处理4龄菜青虫Pieris rapae,测试从苍耳中分离提纯的环氧苍耳素Ⅰ（为倍半萜内酯类物质）对菜青虫中肠蛋白酶、淀粉酶和羧酸酯酶活性的影响。【结果】环氧苍耳素Ⅰ对蛋白酶活性的抑制最强,处理后12,24和48h,菜青虫中肠蛋白酶抑制率分别为20.95%,29.38%和50.06%;其次为淀粉酶,抑制率分别为11.89%,39.01%和31.92%。同时,中肠羧酸酯酶活性在处理后12h与对照之间无显著变化,24h时活性被显著抑制,而48h时活性却明显高于对照。【结论】环氧苍耳素Ⅰ对昆虫中肠消化酶活性的抑制,可能是引起昆虫表现取食抑制和生长发育不良的重要原因之一。

英文摘要：

[Aim] This study aims to reveal the mechanism of epoxyxanthatin Ⅰ （sesquiterpe lactone from Xanthium sibiricum） on Pieris rapae larvae.[Methods] The activity of midgut protease,amylase and carboxylesterase in P.rapae larvae were investigated by feeding to 4th larvae of P.rapae.[Results] Epoxyxanthatin Ⅰ showed the most obvious inhibition on midgut protease,whose activities were inhibited 20.95%,29.38% and 50.06% at 12 h,24 h and 48 h after treatment respectively,while it showed the less obvious inhibition on midgut amylase,whose activities were inhibited 11.89%,39.01% and 31.92%,respectively.Meanwhile,no significant differences in carboxylesterase activity were detected between the controls and the epoxyxanthatin Ⅰ treated samples at 12 h after treatment,while the activity was obviously inhibited at 24 h after treatment and significantly increased at 48 h after treatment compared with that of the control.[Conclusion] The results suggest that the inhibition effect of epoxyxanthatin Ⅰ on midgut digestive enzymes of insects may be one of the causes to inhibit feeding and growth of insects.