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为了研究苦瓜Momordica charantia叶乙酸乙酯萃取物及其活性化合物Momordicin Ⅱ对斜纹夜蛾Spodoptera litura的作用机理,将苦瓜叶乙酸乙酯萃取物及其活性化合物Momordicin Ⅱ添加到人工饲料中饲喂斜纹夜蛾幼虫,分别测定其对斜纹夜蛾幼虫中肠蛋白酶活性和淀粉酶活性的影响。结果表明,斜纹夜蛾幼虫取食了含苦瓜叶乙酸乙酯萃取物的饲料后,其中肠的淀粉酶和蛋白酶活性均比对照明显降低,处理后72h,高浓度(0.08%)对淀粉酶和蛋白酶的抑制率分别为23.0%和40.6%。斜纹夜蛾幼虫取食了含Momordicin Ⅱ的饲料后,对淀粉酶活性无明显的影响,但其中肠的蛋白酶活性比对照明显降低,处理后72h的抑制作用最强,浓度为0.6%时对蛋白酶的抑制率高达75.6%。这些结果说明乙酸乙酯萃取物及其活性化合物Momordicin Ⅱ能够抑制和干扰斜纹夜蛾幼虫中肠的蛋白酶活性和淀粉酶活性,这是中毒斜纹夜蛾幼虫不能正常生长发育的原因之一。
In order to study the mechanism of Momordica charantia leaf ethyl acetate extract and its active compound Momordicin Ⅱ on Spodoptera litura, the ethyl acetate extracts of Momordica charantia and its active compound Momordicin Ⅱ were added into artificial diet to feed twill night Moth larvae, and their effects on midgut protease activity and amylase activity were evaluated respectively. The results showed that the amylose and protease activity of midgut decreased significantly after fed on the ethyl acetate extract containing Momordica charantia leaves. After 72h, the concentration of amylase and protease Protease inhibition rates were 23.0% and 40.6%, respectively. After infestation with Momordicin Ⅱ, the larvae of Spodoptera litura had no significant effect on the amylase activity, but the activity of protease in the intestine was significantly lower than that of the control, and the inhibition was the strongest at 72h after treatment. The protease The inhibition rate was as high as 75.6%. These results indicate that ethyl acetate extract and its active compound Momordicin II can inhibit and interfere with the protease activity and amylase activity in the midgut of the Spodoptera litura larvae, which is one of the reasons why the poisoned Spodoptera litura larvae can not grow normally.