Five monoterpenoid indole alkaloids, namely meloyines A-B (1–2), meloyines II-III (3–4), and 10-O-glucosyl-scandine (5) together with thirty-four known alkaloids were isolated from leaves and twigs of Melodinus yunnanensis. Alkaloid 1 was characterized as an unprecedented skeleton with a 6/5/5/6/6/4 ring system, and alkaloids 3–4 were dimeric monoterpenoid quinolone alkaloids. Their structures were elucidated based on 1D and 2D- NMR, FTIR, UV, and MS spectroscopic data. The cytotoxic activity of new alkaloids were evaluated against three human cancer cell lines.

中文翻译：

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云南Melodinus的新型单萜吲哚生物碱

五个单萜吲哚生物碱，即meloyines AB（1 - 2），meloyines II-III（3 - 4），和10- ö -glucosyl-scandine（5）连同34已知的生物碱是从叶和枝条中分离山橙属云南。生物碱1被表征为具有6/5/5/6/6/4环系统前所未有的骨架，和生物碱3 - 4分别为二聚单萜喹诺酮生物碱。根据1D和2D-NMR，FTIR，UV和MS光谱数据阐明了它们的结构。评价了新生物碱对三种人类癌细胞系的细胞毒活性。