Cyclolobatriene, a novel prenylated germacrene diterpene, from the soft coral Lobophytum pauciflorum
Cyclolobatriene, a novel prenylated germacrene diterpene, from the soft coral Lobophytum pauciflorum
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DOI：
10.1016/j.bmc.2011.12.012
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发表时间：
2012-01-15
影响因子：
3.5
通讯作者：
Ojika, Makoto
中科院分区：
文献类型：
--
作者：
Govindam, Sudhakar V. S.;Yoshioka, Yukio;Ojika, Makoto
从少花Lobophytum pauciflorum中分离得到一个新的10元环二萜化合物cyclolobatriene（1），沿着3个已知的二萜化合物lobatriene（2），eunicol（3），fuscol（4）。它们的结构通过广泛的NMR光谱分析确定。环己三烯（1）是稀有异戊二烯化大根香叶烯的另一个例子。虽然1，由于一个10元环结构，作为三个构象的平衡混合物存在，在CDCl（3）在7摄氏度的NMR测量使我们能够分配的NMR信号的三个，这是第一个完整的NMR分配的所有现有的大根香叶烯型化合物的构象的例子。环己三烯（1）是热不稳定的，在70 ℃加热时通过科普重排转化为2。Eunicol（3）也具有与1相同的异戊二烯化大根香叶烯结构，显示出与1相似的物理化学性质。所有四个化合物1-4对人表皮样癌A431细胞均显示出细胞毒作用，IC（50）分别为0.64、0.41、0.35和0.52 μ M。(C)2011爱思唯尔有限公司保留所有权利。
A new 10-membered-ring diterpene, cyclolobatriene (1), along with three other known diterpenes, lobatriene (2), eunicol (3), and fuscol (4), were isolated from the Okinawan soft coral Lobophytum pauciflorum. Their structures were established by extensive NMR spectroscopic analyses. Cyclolobatriene (1) is an additional example of rare prenylated germacrenes. Although 1, due to a 10-membered-ring structure, exists as an equilibrium mixture of three conformers, the NMR measurement in CDCl(3) at 7 degrees C enabled us to assign the NMR signals of the three, which is the first example of the complete NMR assignment of all the existing conformers of germacrene-type compounds. Cyclolobatriene (1) was thermally unstable and converted into 2 through Cope rearrangement upon heating at 70 degrees C. Eunicol (3) also possesses the same prenylated germacrene structure as 1, showing similar physico-chemical properties to 1. All four compounds 1-4 showed cytotoxic effect with IC(50)'s of 0.64, 0.41, 0.35 and 0.52 mu M, respectively, against human epidermoid carcinoma A431 cells. (C) 2011 Elsevier Ltd. All rights reserved.