Four undescribed alkaloids, namely collacyclumines A-D, along with a known analogue, agrocybenine, were isolated from the endophytic fungus Colletotrichum salsolae SCSIO 41021 derived from the mangrove plant Kandelia candel (L.) Druce. Collacyclumine A represents the first case of dimeric pyrrolidine alkaloid in nature. The structures of these compounds were elucidated by a combination of NMR spectra, HRESIMS data, and X-ray diffraction experiment. A proposed biosynthetic pathway of these isolated compounds were also discussed. None of compounds showed cytotoxic effects against ten cell lines.

中文翻译：

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来自红树林 Kandelia candel 分离的内生真菌 Colletotrichum salsolae SCSIO 41021 的 Collacyclumines A-D

四种未描述的生物碱，即 colacyclumines AD，以及一种已知的类似物 agrocybenine，是从内生真菌 Colletotrichum salsolae SCSIO 41021 中分离出来的，该真菌来源于红树林植物 Kandelia candel (L.) Druce。Collacyclumine A 代表了自然界中第一个二聚吡咯烷生物碱的案例。这些化合物的结构通过 NMR 光谱、HRESIMS 数据和 X 射线衍射实验的组合阐明。还讨论了这些分离化合物的拟议生物合成途径。没有一种化合物对十个细胞系显示出细胞毒性作用。