Developmental Study of New Agricultural Drugs Based on Lipoxygenase Activity

关于水稻植株对稻瘟病菌的抗性，我们已经揭示了氧化不饱和脂肪酸是通过脂氧合酶的作用在水稻植株中代谢的，当水稻植株受到病原菌侵染时，脂氧合酶的活性大大增加。含氧脂肪酸对稻瘟病菌表现出较强的抑制活性。为了寻找受侵染的高等植物体内脂氧合酶活性升高的共性，我们对7种受侵染的高等植物体内的脂氧合酶活性进行了检测，并观察到几种植物的脂氧合酶活性都有较强的增强，特别是在感染TMV和其他病原菌的番茄叶片中。-亚麻酸通过从受感染的番茄叶片制备的脂氧合酶的作用被氧化为相应的烯丙基过氧化氢(I)。经NaBH_4.9S处理后，I被还原为9-羟基衍生物(II)。通过观察相应苯甲酸酯CD谱中的正Cotton效应，阐明了II的绝对构型。还从亚麻酸/脂肪氧合酶氧化反应中分离出几种高氧脂肪酸(III)。过氧化氢(I)显示对所有供试病原菌的活性，而II和III对特定病原菌具有活性。

Concerning the resistancy of rice plants against rice blast fungus, we have already disclosed that oxygenated unsaturated fatty acids are metabolized in the infected rice plant by the action of lipoxygenase, the activity of which increases largely when the rice plants are infected by the pathogen. The oxygenated fatty acids show the strong activity toward the rice blast fungus.In order to find the generality of increments of lipoxygenase activity in the infected higher plants, we examined the activity of lipoxygenase in seven kinds of infected higher plants and observed the strong increase of lipoxygenase activity in several plants, particularly in tomato leaves infected with TMV and other pathogens. -Linolenic acid is oxidized to the corresponding allylic hydroperoxide (I) by the action of lipoxygenase prepared from infected tomato leaves. I was reduced to 9-hydroxy derivative (II) by treatment with NaBH_4.9S absolute configuration of II was elaborated by observation of positive Cotton effect in the CD spectrum of the corresponding benzoate. Several kinds of highly oxygenated fatty acids (III) were also isolated from the -linolenic acid/lipoxygenase oxidation. The hydroperoxide (I) shows the activity to all the pothogens examined while II and III are active to the specific pathogens.