Laboratório de Química Farmacêutica, Departamento de Ciências Farmacêuticas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina-Brasil CEP, 88040-900 Florianópolis, SC, Brazil.
J Agric Food Chem. 2013 Jun 12;61(23):5534-9. doi: 10.1021/jf4002457. Epub 2013 May 31.
Cucurbitacins are secondary metabolites that mediate insect plant interactions not only as allomones against generalists but also as kairomones for specialist herbivores. This study was undertaken to identify the potential of cucurbitacin derivatives as insect antifeedant agents. The antifeedant capacity against a Cucurbitaceae specialist [ Epilachna paenulata (Coleoptera: Coccinellidae)] and a polyphagous insect [ Pseudaletia adultera (Lepidoptera: Noctuidae)] was evaluated in preference tests in which the insects were given a choice between food plants either treated with the cucurbitacin derivatives or treated with the solvent. The activity was found not to be related to the basic cucurbitacin skeleton, as only 15 of the 28 tested cucurbitacin derivatives were active. Only one of the tested compounds was phagostimulant to the specialist insect (the hemissuccinate of 16-oxo-dihydrocucurbitacin B derivative), while all other active derivatives were deterrent against one of the insects (13 compounds) or both of them (3 compounds). Changes in ring A of the cucurbitacins, as well as in the side chain, modified the activity. As a general trend, when chemical modifications of the basic structure produced a change in activity, the response was opposite in both insects used as biodetectors, indicating that a selective variation in the activity may be achieved by chemical modifications of the cucurbitacin skeleton.
葫芦素是介导昆虫与植物相互作用的次生代谢物，不仅作为针对广食性昆虫的化感物质，还作为专食性昆虫的信息素。本研究旨在确定葫芦素衍生物作为昆虫拒食剂的潜力。通过偏好测试评估了葫芦素衍生物对葫芦科专食性昆虫[Epilachna paenulata（鞘翅目：瓢虫科）]和多食性昆虫[Pseudaletia adultera（鳞翅目：夜蛾科）]的拒食能力，昆虫可以在处理过葫芦素衍生物或处理过溶剂的食物植物之间做出选择。研究发现，这种活性与基本的葫芦素骨架无关，因为在测试的 28 种葫芦素衍生物中只有 15 种具有活性。在测试的化合物中，只有一种对专食性昆虫具有取食刺激作用（16-氧代二氢葫芦素 B 衍生物的半琥珀酸酯），而其他所有具有活性的衍生物对其中一种昆虫（13 种化合物）或两种昆虫（3 种化合物）均具有驱避作用。葫芦素中环 A 的变化以及侧链的变化都改变了其活性。一般来说，当基本结构的化学修饰导致活性发生变化时，两种作为生物探测器的昆虫的反应相反，这表明通过葫芦素骨架的化学修饰可以实现活性的选择性变化。
