Royal Botanic Gardens, Kew, Richmond, Surrey TW93AB, UK.
J Chem Ecol. 2011 Mar;37(3):301-10. doi: 10.1007/s10886-011-9918-3. Epub 2011 Feb 18.
Observational studies on foliage avoidance by the polyphagous thrips species Frankliniella occidentalis (Pergande) and Heliothrips haemorrhoidalis (Bouché) (Thysanoptera: Thripidae) identified six non-host species (Allagopappus dichotomus (Asteraceae), Gardenia posoquerioides (Rubiaceae), Plectranthus aff. barbatus, Plectranthus strigosus, Plectranthus zuluensis (Lamiaceae), and Sclerochiton harveyanus (Acanthaceae) among plants growing within a major glasshouse botanical collection. The effects of sequentially obtained acetone and aqueous methanol leaf extracts on mortality in first instar Frankliniella occidentalis were assessed. The acetone leaf extract of Sclerochiton harveyanus, which had the highest activity against the thrips, yielded four new iridoids, sclerochitonosides A-C, and sclerochitonoside B 4'-methyl ether. Mortality of F. occidentalis was increased on exposure to all four iridoids, and the most active iridoid was sclerochitonoside A (8-epiloganic acid 4'-hydroxyphenylethyl ester). Choice experiments demonstrated that this compound did not significantly deter H. haemorrhoidalis from treated leaf surfaces. The significance of iridoids in the defense mechanism of plants against thrips is discussed.
观察多食性蓟马物种西方花蓟马（Pergande）和血红蓟马（Bouché）（缨翅目：蓟马科）避免叶片的研究确定了六种非寄主植物（Allagopappus dichotomus（菊科）、Gardenia posoquerioides（茜草科）、Plectranthus aff. barbatus、Plectranthus strigosus、Plectranthus zuluensis（唇形科）和 Sclerochiton harveyanus（爵床科）），这些植物生长在一个主要的温室植物收藏中。评估了从植物叶片中依次获得的丙酮和甲醇水溶液提取物对初孵期西方花蓟马死亡率的影响。对蓟马活性最高的 Sclerochiton harveyanus 的丙酮叶提取物中分离出四种新的裂环环烯醚萜类化合物，分别为 sclerochitonosides A-C 和 sclerochitonoside B 4'-methyl ether。接触这四种裂环环烯醚萜类化合物后，西方花蓟马的死亡率增加，最活跃的裂环环烯醚萜类化合物是 sclerochitonoside A（8-表告依春酸 4'-羟基苯乙基酯）。选择实验表明，这种化合物并没有显著阻止血红蓟马从处理过的叶片表面逃离。讨论了裂环环烯醚萜类化合物在植物防御蓟马中的意义。
