Constituents of glandular trichomes of Tithonia diversifolia:: Relationships to herbivory and antifeedant activity
Constituents of glandular trichomes of Tithonia diversifolia:: Relationships to herbivory and antifeedant activity
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DOI：
10.1016/j.phytochem.2008.03.019
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发表时间：
2008-07-01
期刊：
影响因子：
3.8
通讯作者：
Da Costa, Fernando Batista
中科院分区：
文献类型：
--
作者：
Ambrsio, Srgio Ricardo;Oki, Yumi;Da Costa, Fernando Batista
本文研究了巴西宽叶甲（Tithonia diversifolia）叶片上的斑缘幼虫（Chlosyne lacinia，鳞翅目）的取食活性及其叶洗液提取物的拒食作用。毛虫只在腺毛密度很低的近轴面取食，而避开含有高水平腺毛的远轴面。在用浓度为鲜叶重量的1-5%的叶冲洗提取物处理的叶圆片中观察到对幼虫的忌避活性。高效液相色谱（HPLC）分析表明，倍半萜内酯是腺毛的主要成分。对叶和花序的二氯甲烷提取物进行了化学研究，分离鉴定了16种化合物：14种倍半萜内酯类、1种黄酮类和1种二萜类。在这项研究中，五个倍半萜内酯是首次在该属，包括两个内酯，其中一个具有不寻常的断愈创木内酯骨架。我们的研究结果表明，毛虫避免倍半内酯丰富的腺毛，并提供证据的二氯甲烷叶冲洗提取物的拒食活性。此外，一个研究的主要成分从叶表面的季节性变化，全年表明，一个非常低的质量，但非常高的数量变化发生。主要代谢产物tagitinin C的最高水平在9月至10月之间，最低水平在3月至6月，后者对应于幼虫最高侵染期。(C)2008爱思唯尔有限公司版权所有。
The herbivory activity of the bordered patch larvae (Chlosyne lacinia, Lepidoptera) on leaves of a Brazilian population of Tithonia diversifolia and the antifeedant potential of its leaf rinse extract were investigated. The caterpillars fed only on the adaxial face, where the density of glandular trichomes is very low, and avoided the abaxial face, which contains high levels of trichomes. Deterrent activity against the larvae was observed in leaf discs treated with leaf rinse extract at concentrations of 1-5% of fresh leaf weight. High-performance liquid chromatography (HPLC) analysis indicated that sesquiterpene lactones are the main constituents of the glandular trichomes. Dichloromethane rinse extracts of the leaves and inflorescences were chemically investigated, and 16 compounds were isolated and identified: 14 sesquiterpene lactones, a flavonoid and a diterpenoid. In this study, five sesquiterpene lactones are described for the first time in the genus, including two lactones, one of which has an unusual seco-guaianolide skeleton. Our findings indicate that the caterpillars avoid the sesquiterpene-lactone-rich glandular trichomes, and provide evidence for the antifeedant activity of the dichloromethane leaf rinse extract. In addition, a study of the seasonal variation of the main constituents from the leaf surface throughout a year demonstrated that a very low qualitative but a very high quantitative variation occurs. The highest level of the main metabolite tagitinin C was observed between September and October and the lowest was from March to June, the later corresponding to the period of highest infestation by the larvae. (C) 2008 Elsevier Ltd. All rights reserved.