Stelleroids A–C, Three Rearranged Guaiane Sesquiterpenoids with Caged Ring Systems from <i>Stellera chamaejasme</i>
Xue Gong, Xiaotian Zhang, Taotao Yuan, Xing Sun, Zhengxi Hu, Jun‐Cheng Su, Weiguang Sun, Luo-Sheng Wan
Abstract
Three highly modified sesquiterpenoids, stelleroids A–C ( 1 – 3, respectively), were isolated from the roots of Stellera chamaejasme . Biosynthetically, these molecules are derived from the 5/7-fused bicyclic guaiane, involving a series of skeletal rearrangements, leading to the formation of an adamantane-like 12-oxa-tetracyclo[6.2.1.1 3,10 .0 3,7 ]dodecane scaffold for 1, a tricyclo[6.2.1.0 2,6 ]undecane backbone for 2, and a tetracyclo[6.2.2.0 1,7 .0 5,11 ]dodecane backbone for 3 . The structures of 1 – 3 were elucidated through a combination of HR-ESI-MS, NMR, quantum chemical calculations, and X-ray diffraction. In the bioassay, compound 1 was identified as the most potent antipulmonary fibrosis lead structure because it significantly inhibited fibroblast proliferation and migration while downregulating the expression of fibrotic markers such as COL1A1 and α-SMA.