Two new highly oxygenated germacranolides, Carpescernolides A (1) and B (2), were isolated from the whole plant of Carpesium cernuum. Their structures were established by extensive analysis of NMR spectra, as well as HRESIMS data. X-ray diffraction studies were used to confirm the absolute configurations of 1 and 2. Notably, compound 1, with an oxygen bridge unit (C-2–O-C-5) and a 4, 8-ketal system at C-8, resulted in a novel type of germacranolide compound. Compound 1 showed a moderate inhibition against SMMC-7721 cancer cells in vitro.

中文翻译：

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Carpescernolides A和B，来自于Carpesium cernuum的稀有含氧桥的倍半萜内酯

两个新的高度氧化germacranolides，Carpescernolides A（1）和乙（2）中，从全植物中分离天名cernuum。通过对NMR光谱以及HRESIMS数据进行广泛的分析，确定了它们的结构。X射线衍射研究用于确认1和2的绝对构型。值得注意的是，具有氧桥单元（C-2–OC-5）和C-8处的4、8-缩酮系统的化合物1产生了一种新型的germ草内酯化合物。化合物1在体外显示出对SMMC-7721癌细胞的中等抑制作用。