(±)-Ganoapplanin, a Pair of Polycyclic Meroterpenoid Enantiomers from <i>Ganoderma applanatum</i>

(±)-Ganoapplanin (1), a pair of novel meroterpenoid enantiomers featuring an unprecedented dioxaspirocyclic skeleton constructed from a 6/6/6/6 tetracyclic system and an unusual tricyclo­[4.3.3.03′,7′]­dodecane motif, were isolated from Ganoderma applanatum. Its structure and absolute configurations were determined by spectroscopic analyses, X-ray crystallography, and ECD (electronic circular dichroism calculations). A plausible biogenetic pathway, involving a key Gomberg–Bachmann reaction, was also proposed for (±)-1. Biological studies showed that (±)-1 and its enantiomers exhibited different inhibitory activities on T-type voltage-gated calcium channels.(±)-Ganoapplanin（化合物1）为一对新型杂萜（meroterpenoid）对映异构体，其拥有前所未有的二氧杂螺环骨架，该骨架由6/6/6/6四环体系与罕见的三环[4.3.3.03′,7′]十二烷母核构建而成，分离自平盖灵芝（Ganoderma applanatum）。其结构与绝对构型通过波谱分析、X射线晶体衍射以及电子圆二色谱（electronic circular dichroism, ECD）计算得以确定。研究还针对(±)-1提出了一条合理的生源合成途径，该途径涉及关键的戈姆伯格-巴克曼（Gomberg–Bachmann）反应。生物学研究表明，(±)-1及其对映异构体对T型电压门控钙通道展现出不同的抑制活性。