Laboratorio de Ecología Química, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Casilla 54-D, Temuco 4811230, Chile.
Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Universidad de La Frontera, Casilla 54-D, Temuco 4811230, Chile.
Molecules. 2018 May 27;23(6):1282. doi: 10.3390/molecules23061282.
The beetle Marsham (Coleoptera: Curculionidae), endemic to Europe and Northern Africa, is one of the most important red clover pests in Chile. As commercial insecticides are less effective against this pest, plant secondary metabolites have been considered as an alternative for its control. Here, we have investigated the chemical composition of essential oil (EO), petroleum ether extract (PEE), and dichloromethane extract (DCME) from heartwood. Additionally, the effects of EO and extracts on the feeding behavior (% of weight shift) of have been evaluated. The composition of EO, PEE, and DCME were analyzed using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The results showed the presence of a similar mixture of sesquiterpenes in the essential oil and in both of the extracts, which accounted for circa 60% of the total mixture. Sesquiterpenes were further isolated using chromatographic methods and were structurally characterized by optical rotation, GC⁻MS, FTIR, and 1D and 2D NMR experiments. The physicochemical properties of the isolated sesquiterpenes, including lipophilicity and vapor pressure, were also determined. The sesquiterpenes were identified as the following: (-)--calamenene (), cadalene (), (-)-cubenol (), (-)--cubenol (), (-)-torreyol (), and (-)-15-copaenol (). The antifeedant activity of EO, extracts, and isolated sesquiterpenes were evaluated using artificial diets in a non-choice test. Relative to the control, the EO, DCME extract, and the isolated sesquiterpenes, namely, (-)--calamenene (), cadalene (), and () torreyol, were found to be the most effective treatments against . Our study showed that the compounds occurring in heartwood were effective in reducing the adult growth of . The physicochemical properties of the isolated sesquiterpenes might have been associated with antifeedant effects.
欧洲和北非特有的鳃角金龟（鞘翅目：象甲科）是智利最重要的红三叶草害虫之一。由于商业杀虫剂对这种害虫的效果较差，因此人们认为植物次生代谢物是其防治的一种替代方法。在这里，我们研究了心材的精油（EO）、石油醚提取物（PEE）和二氯甲烷提取物（DCME）的化学成分。此外，还评估了 EO 和提取物对 的摄食行为（体重转移百分比）的影响。使用气相色谱（GC）和气相色谱/质谱（GC/MS）分析了 EO、PEE 和 DCME 的成分。结果表明，在精油和两种提取物中存在类似的倍半萜混合物，占总混合物的约 60%。使用色谱方法进一步分离倍半萜，并通过旋光度、GC-MS、FTIR 以及 1D 和 2D NMR 实验对其结构进行了表征。还确定了分离出的倍半萜的物理化学性质，包括脂溶性和蒸气压。分离出的倍半萜被鉴定为以下物质：(-)--calamenene ()、cadalene ()、(-)-cubenol ()、(-)--cubenol ()、(-)-torreyol () 和 (-)-15-copaenol ()。在非选择试验中，使用人工饲料评估了 EO、提取物和分离出的倍半萜对 的抗食作用。与对照相比，EO、DCME 提取物和分离出的倍半萜，即(-)--calamenene ()、cadalene ()和() torreyol，对 最有效。我们的研究表明，存在于心材中的化合物可有效降低 的成虫生长。分离出的倍半萜的物理化学性质可能与其抗食作用有关。
