From two species of Sutera (S. foetida and S. cordata) (Scrophulariaceae tribe Limoselleae) were isolated three known secoiridoid glucosides (12-14) as well as four iridoid congeners (8-11), all biosynthetically derived from iridodial glucoside (and/or deoxyloganic acid). In addition, two previously unknown compounds were found, namely a terpenoid glucoside lactone (suterolide, 21) and the phenylethanoid glycoside 2''''-O-acetyl-angoroside A (19) as well as verbascoside, echinacoside and tubuloside A(15-17, respectively). Two other species, Jamesbrittenia dissecta and Lyperia antirrhinoides, previously considered to belong to the same genus (Sutera) were shown to be members of two different genera, respectively. Significantly, these two species contained iridoids derived from 8-epi-iridodial (and 8-epideoxyloganic acid), namely aucubin (2), melittoside (3) and acetylharpagide (4). In addition we investigated Melanospermum transvaalense, Lyperia tristis and Microdon dubius likewise from Limoselleae and all of these contained iridoid glucosides from the 8-epi-pathway. Thus, secoiridoid distribution confirms the DNA-based circumscription of Sutera and its sister-group relationship with Manulea. In addition, the results show that the clade including these two genera has a biosynthetic pathway to iridoids fundamentally different from the rest of the tribe and from the whole family Scrophulariaceae.

中文翻译：

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Sutera 属（玄参科）中的环烯醚萜苷作为 Limoselleae 部落的化学分类标记

从两种 Sutera（S. foetida 和 S. cordata）（玄参科 Limoselleae）中分离出三种已知的环环烯醚萜苷 (12-14) 以及四种环环烯醚萜类同系物 (8-11)，所有这些都是生物合成衍生自环烯醚萜苷（和/或脱氧原酸）。此外，还发现了两种以前未知的化合物，即萜类糖苷内酯（suterolide，21）和苯乙醇苷 2''''-O-乙酰-安哥罗苷 A（19）以及毛蕊花苷、松果菊苷和管苷 A（15） -17，分别）。之前被认为属于同一属（Sutera）的另外两个物种 Jamesbrittenia dissecta 和 Lyperia antirrhinoides 分别被证明是两个不同属的成员。值得注意的是，这两个物种含有衍生自 8-epi-iridodial（和 8-epideoxyloganic acid）的环烯醚萜，即 aucubin (2)、melittoside (3) 和 acetylharpagide (4)。此外，我们还研究了来自 Limoselleae 的 Melanospermum transvaalense、Lyperia tristis 和 Microdon dubius，并且所有这些都含有来自 8-epi-pathway 的环烯醚萜苷。因此，secoiridoid 分布证实了基于 DNA 的 Sutera 范围及其与 Manulea 的姐妹群关系。此外，结果表明，包括这两个属的进化枝具有与其他部落和整个玄参科完全不同的环烯醚萜生物合成途径。secoiridoid 分布证实了基于 DNA 的 Sutera 范围及其与 Manulea 的姐妹群关系。此外，结果表明，包括这两个属的进化枝具有与其他部落和整个玄参科完全不同的环烯醚萜生物合成途径。secoiridoid 分布证实了基于 DNA 的 Sutera 范围及其与 Manulea 的姐妹群关系。此外，结果表明，包括这两个属的进化枝具有与其他部落和整个玄参科完全不同的环烯醚萜生物合成途径。