Icacinlactone H and Icacintrichantholide from the Tuber of Icacina trichantha

The
17-norpimarane diterpene is a small group of natural products.
A new member, icacinlactone H (1), and a new rearranged
17-norpimarane with an unprecedented carbon skeleton, icacintrichantholide
(2), were isolated from Icacina trichantha. Their structures including the absolute configuration were elucidated
by spectroscopic analysis, single-crystal X-ray diffraction, and electronic
circular dichroism analysis. A plausible biogenetic pathway for 1 and 2 is proposed. Both 1 and 2 showed no significant activity against herpes simplex viruses
HSV-1 and HSV-2 as well as the Epstein–Barr virus at 50 μM.

17-诺皮马烷二萜烯是一类小型的天然产物。从三裂伊卡宁（Icacina trichantha）中分离得到一种新成员，即伊卡宁内酯H（1），以及一种具有前所未有的碳骨架的重新排列的17-诺皮马烷，即伊卡宁三香叶内酯（2）。通过光谱分析、单晶X射线衍射以及电子圆二色性分析，阐明了它们的结构，包括绝对构型。针对1和2的生物合成途径提出了一个合理的假设。在50 μM的浓度下，1和2对单纯疱疹病毒HSV-1和HSV-2以及爱泼斯坦-巴尔病毒均未表现出显著的活性。