Insect pheromone biosynthesis: stereochemical pathway of hydroxydanaidal production from alkaloidal precursors in Creatonotos transiens (Lepidoptera, Arctiidae).

The mechanism by which the moth Creatonotos transiens produces its male pheromone, (7R)-hydroxydanaidal, from heliotrine, an alkaloidal precursor of opposite (7S) stereochemistry, was investigated. Specifically deuteriated samples of heliotrine and epiheliotrine were prepared and fed to C. transiens larvae, and the steps in the biosynthetic process were monitored by gas chromatography/mass spectrometry. These analyses indicate that heliotrine is initially epimerized to (7S)-epiheliotrine by oxidation to the corresponding ketone followed by stereospecific reduction. The order of the subsequent steps is (i) aromatization of the dihydropyrrole ring, (ii) ester hydrolysis, and (iii) oxidation of the resulting primary alcohol to the final aldehyde. The ecological implications of this insect's ability (and the inability of another moth, Utetheisa ornatrix) to use representatives of two stereochemical families of alkaloids as pheromone precursors are discussed.

本研究针对透翅鹿蛾（Creatonotos transiens）从具有相反(7S)立体构型的生物碱前体天芥菜碱（heliotrine）合成雄性信息素(7R)-羟基达纳纳尔((7R)-hydroxydanaidal)的生物合成机制展开了系统探究。研究人员制备了氘代的天芥菜碱与表天芥菜碱（epiheliotrine）样品，并将其饲喂至透翅鹿蛾幼虫体内，随后通过气相色谱-质谱联用法（gas chromatography/mass spectrometry, GC/MS）对生物合成过程中的各步骤进行监测。分析结果显示，天芥菜碱首先经氧化反应生成对应的酮中间体，再通过立体专一性还原作用发生差向异构，转化为(7S)-表天芥菜碱。后续生物合成步骤依次为：(i) 二氢吡咯环的芳构化修饰；(ii) 酯水解反应；(iii) 将生成的伯醇氧化为最终的醛基产物。本研究还探讨了该昆虫具备利用两类立体化学家族生物碱作为信息素前体的能力，而另一种蛾类——饰腹灯蛾（Utetheisa ornatrix）则不具备该能力的生态学意义。