Five previously undescribed monoterpenoid indole alkaloids, mappianines A-E, along with twelve known analogues, were isolated from the stems of Mappianthus iodoides Hand.-Mazz. Their structures and absolute configurations were determined by spectroscopic analysis, single-crystal X-ray diffraction, and ECD calculations. The plausible biogenetic pathway of mappianine A was proposed. All the isolated compounds were evaluated for their cytotoxic effects on MGC-803, Bel-7404, A549, NCI-H460, and HepG2 cancer cell lines. Mappianine B, tetrahydroalstonine, β-carbolin-1-one, and 1,2,3,4-tetrahydronorharman-1-one displayed moderate cytotoxicity against all cell lines tested, with IC50 values ranging from 5.19 to 42.86 μM.

中文翻译：

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Mappianines A-E，来自 Mappianthus iodoides 的结构多样的单萜吲哚生物碱

从 Mappianthus iodoides Hand.-Mazz 的茎中分离出五种以前未描述的单萜吲哚生物碱、mappianines AE 以及 12 种已知的类似物。它们的结构和绝对构型是通过光谱分析、单晶 X 射线衍射和 ECD 计算确定的。提出了 mappianine A 的似是而非的生物遗传途径。评估了所有分离的化合物对 MGC-803、Bel-7404、A549、NCI-H460 和 HepG2 癌细胞系的细胞毒性作用。Mappianine B、四氢石氨酸、β-carbolin-1-one 和 1,2,3,4-四氢norharman-1-one 对所有测试的细胞系均显示出中等的细胞毒性，IC50 值范围为 5.19 至 42.86 μM。