Thirteen undescribed dimeric guaianes were isolated from the leaves of Xylopia vielana Pierre. Their structures were elucidated by NMR spectroscopy and mass spectrometry, and the absolute configurations of vielanins G-Q were determined by a combination of the circular dichroism (CD) exciton chirality method, chemical conversion, and electronic CD (ECD) spectroscopy analysis. Vielaninors A and B are the first examples of trinor-guaiane-dimers. Multidrug resistance reversal activity assay of the isolates was evaluated in doxorubicin-resistant human breast cancer cells. Vielanins H, K-M, P, and Q were noncytotoxic and enhanced the cytotoxicity of doxorubicin by 2.1-41.6-fold at 10 μM.

中文翻译：

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罕见的维拉纳木瓜二聚体愈创木酚二聚体及其多药耐药逆转活性

从 Xylopia vielana Pierre 的叶子中分离出 13 种未描述的二聚愈创木脂。它们的结构通过核磁共振谱和质谱法阐明，维拉宁 GQ 的绝对构型通过圆二色性 (CD) 激子手性方法、化学转化和电子 CD (ECD) 光谱分析的组合确定。Vielaninors A 和 B 是trinor-guaiane-dimers 的第一个例子。在多柔比星抗性人乳腺癌细胞中评估了分离物的多药抗性逆转活性测定。Vielanins H、KM、P 和 Q 是无细胞毒性的，并且在 10 μM 时将阿霉素的细胞毒性提高了 2.1-41.6 倍。