An unusual spirocyclic isopimarane diterpenoid and other isopimarane diterpenoids from fruiting bodies of Xylaria polymorpha

- A new isopimarane diterpene, spiropolin A was isolated from Xylaria polymorpha.
- The structure of spiropolin A was elucidated on the basis of chemical and spectroscopic data and crystal X-ray structural analysis.
- Spiropolin A restored the growth inhibition caused by the hyperactivated Ca2+-signaling.