Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, D-26129 Oldenburg, Germany.
Phytochemistry. 2012 Mar;75:114-27. doi: 10.1016/j.phytochem.2011.11.019. Epub 2011 Dec 22.
Thevetia cardiac glycosides can lead to intoxication, thus they are important indicators for forensic and pharmacologic surveys. Six thevetia cardiac glycosides, including two with unknown structures, were isolated from the seeds of the Yellow Oleander (Thevetia peruviana (Pers.) K. Shum., Apocynaceae). LC-ESI⁺-MS(/MS) analysis under high-resolution conditions used as a qualitative survey of the primary glycosides did not lead to fragmentation of the aglycones. Acid hydrolysis of the polar and non-volatile thevetia glycosides under severe conditions yielded the aglycones of the thevetia glycosides and made them amenable to GC-MS analysis. Comparison of mass spectral fragmentation patterns of the aglycones, as well as high-resolution mass spectrometric and NMR data of four of the primary thevetia glycosides including the two unknowns, revealed the structures of the complete set of six thevetia glycosides. The identified compounds are termed thevetin C and acetylthevetin C and differ by an 18,20-oxido-20,22-dihydro functionality from thevetin B and acetylthevetin B, respectively. The absence of an unsaturated lactone ring renders the glycosides cardio-inactive. The procedures developed in this study and the sets of analytical data obtained will be useful for screening and structure assessment of other, particularly polar, cardiac glycosides.
黄夹竹桃（Thevetia peruviana (Pers.) K. Shum., Apocynaceae）种子中分离得到了 6 种黄夹竹桃强心苷，包括 2 种未知结构的苷。在高分辨条件下，LC-ESI⁺-MS(/MS)分析作为初级糖苷的定性调查，并没有导致苷元的断裂。在苛刻条件下对极性和非挥发性黄夹竹桃苷进行酸水解，得到了黄夹竹桃苷的苷元，使其能够进行 GC-MS 分析。对苷元的质谱裂解模式进行比较，以及对包括 2 种未知物在内的 4 种初级黄夹竹桃苷的高分辨质谱和 NMR 数据进行比较，揭示了这 6 种黄夹竹桃苷的完整结构。鉴定出的化合物分别被称为黄夹竹桃苷 C 和乙酰黄夹竹桃苷 C，它们分别与黄夹竹桃苷 B 和乙酰黄夹竹桃苷 B 相差 18,20-氧化-20,22-二氢功能基。由于不存在不饱和内酯环，糖苷具有心脏活性。本研究中建立的方法和获得的分析数据集将有助于筛选和评估其他特别是极性的强心苷。
