Effect of iridoid glycoside content on oviposition host plant choice and parasitism in a specialist herbivore

The Glanville fritillary butterfly Melitaea cinxia feeds upon two host plant species in Å land, Finland, Plantago lanceolataand Veronica spicata, both of which produce iridoid glycosides. Iridoids are known to deter feeding or decrease the growth rate of many generalist insect herbivores, but they often act as oviposition cues to specialist butterflies and are feeding stimulants to their larvae. In this study, two iridoid glycosides (aucubin and catalpol) were analyzed by micellar electrokinetic capillary chromatography. We measured the spatial and temporal variation of iridoid glycosides in natural populations of the host plants of M. cinxia. We also analyzed the aucubin and catalpol content in plants in relation to their use by ovipositing females, and in relation to the incidence of parasitism of M. cinxia larvae in natural populations. The mean concentrations of aucubin and catalpol were higher in P. lanceolata than in V. spicata, and catalpol concentrations were higher than aucubin concentrations in both host species. Plantago lanceolata individuals that were used for oviposition by M. cinxia had higher aucubin concentrations than random plants and neighboring plants. Additionally, oviposition and random plants had higher catalpol concentrations than neighboring plants, indicating that ovipositing females select for high iridoid glycoside plants or that oviposition induces iridoid glycoside production in P. lanceolata. Parasitism by the specialist parasitoid wasp Cotesia melitaearum occurred most frequently in larval groups that were feeding on plants with low concentrations of catalpol, irrespective of year, population, and host plant species. Therefore, parasitoids appear to avoid or perform poorly in host larvae with high catalpol content.     

Patterns of Iridoid Glycoside Production and Induction in Plantago lanceolata and the Importance of Plant Age

Induction of allelochemicals is one way that plants efficiently deploy defenses against herbivory. In two separate experiments we investigated the time course of this inductive response and the importance of the timing of herbivory for Plantago lanceolata (Plantaginaceae). We found a localized induced response of catalpol and the ratio of catalpol to total iridoid glycosides in damaged leaves that was evident at d 6 after caterpillars of the specialist Junonia coenia were put onto the plants. On the whole plant level, we detected small, but significant changes in the iridoid glycoside metabolism of P. lanceolata on several different days following herbivory. We also found considerable change in the amounts of allelochemicals produced during P. lanceolata's ontogeny. This ontogenetic effect might help to explain some of the reasons why induction may be difficult to detect in P. lanceolata. We also investigated the importance of the timing of herbivory on P. lanceolata's inductive response, but neither herbivory after 5 wk of growth nor after 6 or 7 wk of growth induced an increase in aucubin or catalpol.     

杜仲翅果桃叶珊瑚甙抗氧化活性的研究

[目的]研究杜仲翅果桃叶珊瑚甙体外抗氧化活性。[方法]以抗坏血酸为对照,采用分光光度法测定杜仲翅果桃叶珊瑚甙对羟自由基、超氧阴离子自由基、过氧化氢自由基的清除作用。[结果]杜仲翅果桃叶珊瑚甙对上述自由基均有清除作用,过氧化氢自由基清除效果比抗坏血酸好,清除羟自由基和超氧阴离子自由基能力弱于抗坏血酸。[结论]杜仲翅果桃叶珊瑚甙具有一定的清除自由基的作用。     

硅胶柱层析法分离纯化杜仲粕中桃叶珊瑚苷

探讨使用硅胶柱层析法从杜仲粕中分离纯化桃叶珊瑚苷(Au),优化柱层析吸脱附条件,用薄层色谱法(TLC)和高效液相色谱法(HPLC)对产品进行定性定量分析。结果表明：优化的硅胶用量为生药质量的2 倍,使用V(甲醇):V(氯仿):V(石油醚):V(乙酸乙酯)为7:1:0.5:1.5 的混合溶剂在1.0mL/min 流速下进行洗脱,通过收集含Au高的组分,经减压浓缩、结晶、过滤、重结晶等过程,可获纯度为96.56% 的桃叶珊瑚苷产品。     

醇洗法提取杜仲籽仁粕中桃叶珊瑚苷及制取浓缩蛋白

以杜仲籽仁粕为原料,利用醇洗工艺提取桃叶珊瑚苷同时制备浓缩蛋白,并采用高效液相色谱法(HPLC-UV)检测杜仲籽仁及其粕、浓缩蛋白中桃叶珊瑚苷含量。结果表明:不同产地杜仲籽仁及其粕中桃叶珊瑚苷含量分别为6.86%~15.44%、5.25%~16.60%。利用含水乙醇对杜仲籽仁粕进行醇洗时,浓缩蛋白和提取液均会变黑,且基本检测不出桃叶珊瑚苷。只有用无水乙醇作为醇洗溶剂时,才能得到乳白色的浓缩蛋白和富含桃叶珊瑚苷的提取液,此时浓缩蛋白的蛋白质含量达到51.78%,较杜仲籽仁粕中提高16.54个百分点。以无水乙醇为溶剂提取杜仲籽仁粕中的桃叶珊瑚苷,最佳提取条件为提取温度80℃、提取时间20 min、液料比8∶1、提取次数2次。在最佳提取条件下,桃叶珊瑚苷的提取率达到94.82%。     

Iridoid glycosides as oviposition stimulants for the buckeye butterfly,Junonia coenia (Nymphalidae)

Females ofJunonia coenia (Nymphalidae), a specialist on plants that contain iridoid glycosides, were found to use aucubin and catalpol, iridoid glycosides typical of a host plant,Plantago lanceolata (Plantaginaceae), as oviposition cues. Incorporating dried ground leaf material or pure iridoid glycosides into agar disks proved to be a very effective method of testing. In no-choice tests and choice tests, females laid more eggs on disks withP. lanceolata leaf material or iridoid glycosides, compared to agar controls. There was variation among individual females in preference for disks withP. lanceolata leaf material versus disks with iridoid glycosides. Females given a choice of three different concentrations of iridoid glycoside (0.2, 0.5, 1.0%) in the agar disks and a control laid more eggs on the disk with the highest concentration of iridoid glycoside.     

正交实验优化杜仲叶中桃叶珊瑚甙提取工艺

以杜仲叶为原料,丙酮-水体系作溶剂对桃叶珊瑚甙提取工艺进行了研究,采用单因素试验和正交试验法对桃叶珊瑚甙的提取工艺条件进行优化.研究表明,桃叶珊瑚甙提取的最佳工艺条件为:丙酮浓度50%,提取温度65℃,提取时间1 h,料液比1∶16,在中性条件下提取两次.在最佳工艺条件下,桃叶珊瑚甙提取率1.86%,提取物得率16.93%,纯度为11.0%.     

车前草中桃叶珊瑚苷提取工艺的优化

对车前草中桃叶珊瑚苷的提取工艺进行了优化。通过单因素实验就提取溶剂甲醇体积分数、料液比、提取温度、提取时间、提取次数对桃叶珊瑚苷提取效果的影响进行了研究,在此基础上通过正交实验确定桃叶珊瑚苷最佳提取条件为：甲醇体积分数80％、料液比1：20（g：mL）、提取温度70℃、提取时间1．5h,在此条件下,桃叶珊瑚苷得率为0．80％。     

杜仲翅果桃叶珊瑚甙抗氧化稳定性研究

以杜仲翅果桃叶珊瑚甙还原力的活性变化为指标,研究了温度和光线对杜仲翅果桃叶珊瑚甙抗氧化稳定性的影响。结果表明:高温和光照对抗氧化活性影响很大,平时应该在低温、避光环境中保存。     

超声波辅助提取杜仲翅果桃叶珊瑚甙工艺优化

目的：研究超声波辅助提取杜仲翅果中桃叶珊瑚甙的较佳工艺条件,为杜仲翅果资源的综合开发利用提供参考。方法：在单因素试验的基础上,通过Box-Behnken试验设计确定乙醇体积分数、超声波功率、提取时间及液料比等因素的最佳工艺条件。结果：超声波辅助提取杜仲翅果中桃叶珊瑚甙的最佳提取工艺条件为乙醇体积分数72.1%、超声波功率300W,提取时间20.5min、液料比12.3:1(mL/g),在该条件下杜仲翅果桃叶珊瑚甙的实际提取率为5.91%。在试验范围内各因素对桃叶珊瑚甙得率影响大小依次为乙醇体积分数＞料液比＞提取时间。结论：超声波辅助提取法能够较好地提取杜仲翅果桃叶珊瑚甙。