The first phytochemical examination of extracts from leaves and stem bark of Palicourea luxurians (Rusby) Borhidi yielded two undescribed and one known alstrostine derivative together with the oxindole alkaloid javaniside as well as with 5α-carboxystrictosidine. Additionally, five iridoids and four secologanin derived isolation artifacts have been isolated. Lack of strictosidine and its follow-up metabolization products suggested that the Pictet-Spenglerase in P. luxurians does barely or not catalyze the formation of strictosidine. Against this background the biosynthesis of javaniside and 5α-carboxystrictosidine is discussed with regard to possible reaction mechanisms. Similarly, P. luxurians used an independent biosynthetic pathway to produce alstrostine type structures from secologanin and tryptamine in a 2:1 ratio. The structure of isoalstrostine A, which was isolated for the first time, allowed the refinement of a previously reported pathway to the alstrostine type carbon skeleton as well as to some follow-up metabolization products. In spite of various biosynthetic pathways incorporating secologanin to gain different types of tryptophan- and tryptamine-iridoid alkaloids, P. luxurians accumulates this compound as well a couple of further metabolized iridoids deriving from loganin and secologanin.

中文翻译：

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Palicourea luxurians（茜草科：Palicoureeae）的生物碱和环烯醚萜苷表明色胺和色氨酸环烯醚萜生物碱的形成与胡豆苷途径不同

Palicourea luxurians (Rusby) Borhidi 的叶子和茎皮提取物的第一次植物化学检查产生了两种未描述的和一种已知的 alstrostine 衍生物以及 oxindole 生物碱 javaniside 以及 5α-carboxystrictosidine。此外，还分离了 5 个环烯醚萜类化合物和 4 个 secologanin 衍生的分离工件。胡桃苷及其后续代谢产物的缺乏表明 P. luxurians 中的 Pictet-Spenglerase 几乎不催化或不催化胡豆苷的形成。在此背景下，关于可能的反应机制讨论了鸦胆碱苷和 5α-羧基豆蔻苷的生物合成。类似地，P. luxurians 使用独立的生物合成途径，以 2:1 的比例从 secologanin 和色胺中产生 alsstromtine 型结构。首次分离出的异奥斯汀 A 的结构允许改进先前报道的通往阿尔斯特斯汀型碳骨架以及一些后续代谢产物的途径。尽管各种生物合成途径结合了赛洛加宁来获得不同类型的色氨酸和色胺环烯醚萜生物碱，但 P. luxurians 积累了这种化合物以及一些源自马钱苷和赛洛加宁的进一步代谢的环烯醚萜。