1H NMR-Guided Isolation of Formyl-Phloroglucinol Meroterpenoids from the Leaves of Eucalyptus robusta
1H NMR-Guided Isolation of Formyl-Phloroglucinol Meroterpenoids from the Leaves of Eucalyptus robusta
复制标题
H-1 NMR 引导下从粗桉叶中分离甲酰基间苯三酚半萜类化合物
DOI：
10.1002/chem.201601732
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发表时间：
2016-08-08
影响因子：
4.3
通讯作者：
Kong, Ling-Yi
中科院分区：
文献类型：
--
作者：
Shang, Zhi-Chun;Yang, Ming-Hua;Kong, Ling-Yi
通过跟踪酚羟基H-1核磁共振峰，从粗大桉叶中分离得到9个甲酰基间苯三酚类化合物，分别为桉树酮A-I(1-9)。采用Snatzke螺旋度规则对扭曲苯环的棉花效应进行了研究，确定了FPM的绝对构型。这些发现，连同核磁共振光谱，圆二色(CD)激子手性方法和CD计算，使完整的结构得以指认。丁香酮A-F(1-6)是间苯三酚环上的甲酰基碳原子与单萜和倍半萜组分形成的新型加合物。Eucalrobusones G-I(7-9)是第一批具有立方烷部分结构的FPM，通过一个不寻常的1-氧杂螺[5.5]十一烷亚单位连接。在这些菌株中，尤卡罗布松C(3)对HepG2、MCF-7和U2OS癌细胞具有明显的细胞毒作用，其IC50值小于10 mM。化合物3可显著抑制MCF-7细胞的增殖，并通过诱导细胞凋亡诱导细胞死亡。
Nine formyl-phloroglucinolmeroterpenoids (FPMs), namely, eucalrobusones A-I (1-9), were isolated from the leaves of Eucalyptus robusta by tracking the phenolic hydroxyl H-1 NMR peaks. The Snatzke helicity rules for the Cotton effects of twisted benzene rings were applied to elucidate the absolute configurations of the FPMs. These findings, along with NMR spectroscopy, the circular dichroism (CD) exciton chirality method, and CD calculations, allowed complete structures for the FPMs to be assigned. Eucalrobusones A-F (1-6) are novel adducts formed between a formyl-derived carbon atom on the phloroglucinol ring and monoterpene and sesquiterpene components. Eucalrobusones G-I (7-9) are the first examples of FPMs with cubebane part structures connected by an unusual 1-oxaspiro[5.5] undecane subunit. Among these isolates, eucalrobusone C (3) showed significant cytotoxicity against HepG2, MCF-7, and U2OS cancer cell lines, with IC50 values less than 10 mm. Compound 3 significantly blocks cell proliferation in MCF-7 cells and induces MCF-7 cell death through apoptosis.