Developmental Study of New Agricultural Drugs Based on Lipoxygenase Activity

关于水稻植物对稻瘟病真菌的抗性，我们已经公开了氧化不饱和脂肪酸在感染的水稻植物中通过脂氧合酶的作用代谢，当水稻植物被病原体感染时，脂氧合酶的活性大大增加。含氧脂肪酸对稻瘟病菌具有较强的活性，为了探讨脂氧合酶活性在感染病菌的高等植物中的普遍性，我们测定了7种感染病菌的高等植物的脂氧合酶活性，发现在几种植物中脂氧合酶活性明显增加，特别是在感染TMV等病菌的番茄叶片中。- 亚麻酸通过由感染的番茄叶制备的脂氧合酶的作用被氧化成相应的烯丙基氢过氧化物（I）。用NaBH_4还原Ⅰ得到9-羟基衍生物（Ⅱ）。通过观察相应苯甲酸酯的圆二色谱中的正Cotton效应，阐明了Ⅱ的9 S绝对构型。几种高度氧化的脂肪酸（III）也被分离的-亚麻酸/脂氧合酶氧化。氢过氧化物（I）对所有检测的病原体都有活性，而氢过氧化物（II）和氢过氧化物（III）对特定病原体有活性。

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.