氧肟酸的次生代谢及其对昆虫生理毒性研究

PROGRESS IN STUDIES OF SECONDARY METABOLISM OF HYDROXAMIC ACIDS AND THEIR PHYSIOLOGICAL TOXICITY TO INSECTS

氧肟酸是禾本科植物中与自身化学防御系统有密切关系的重要次生代谢物质。氧肟酸的合成基因位点存在于Bx系统,其生物合成机制与色氨酸相似。通过对植物内生性轮状镰刀霉(Fusarium verticillioides)的研究表明,丁布的生物降解产物主要为HMPMA,AMPO,BOA-X。与亲核试剂的反应、对氨基酸衍生物进行蛋白质修饰的功能等均是氧肟酸的生物学效应原理,如对硫氢基等进行攻击反应。昆虫体内3大营养物质的代谢及呼吸链的电子传递能被丁布所抑制,表现出其对昆虫的生理毒性作用。

Hydroxamic acids, a group of important secondary metabolites, are closely associated with the chemical self-defense system in gramineous plants. The Bx system is responsible for the gene locus for its biosynthesis that is similar to the pathway of tryptophane produc- tion. Studies on the endophytic fungus Fusarium verticillioides show that the major biological products of DIMBOA decomposition are HMPMA, AMPO and BOA-X. Reacting with nucleophile and proteinaceous modification of amino-acid derivatives are the principles of biological activity of DIMBOA. The metabolism of nutrient substances and electron transport of respiratory chain in the insect body will be inactivated by DIMBOA, which is shown as its physiological toxicity to insects.