(±)‐Atrachinenins A—C, Three Pairs of Caged <scp>C<sub>27</sub></scp> Meroterpenoids from the Rhizomes of <i>Atractylodes chinensis</i>
Feilong Chen, Dongli Liu, Jing Fu, Ji Yang, Li‐Ping Bai, Wei Zhang, Zhi‐Hong Jiang, Guo‐Yuan Zhu
Abstract
Comprehensive Summary (±)‐Atrachinenins A—C (1—3), three meroterpenoids possessing novel C 27 skeletons, were isolated from the rhizomes of Atractylodes chinensis . (±)‐Atrachinenin A (1) possesses an unprecedented cage‐like skeleton with a fused 6/6/5/5 tetracyclic system (decahy‐dro‐1,5:4a,7‐dimethanobenzo[7]annulene), which may be formed by the intermolecular cyclization of (±)‐atrachinenin C (3). Compared to 1, (±)‐atrachinenin B (2) features an additional unique five‐membered peroxyl bridge ring to form a complex 6/6/5/5/5 cyclic ring system. Their structures and absolute configurations were elucidated by HRESIMS, NMR spectroscopic data, ECD calculation, and X‐ray diffraction. A plausible biogenetic pathway was proposed. Compound 1 exhibited potential TGF‐ β inhibitory activity at 25 μmol/L.