Caryolane-type sesquiterpenes from Cirsium souliei

- A new caryolane-type sesquiterpene 1 and its isomer 2 at C-12 were reported.
- Their absolute configurations were assigned by comparison of the experimental results with calculated optical rotations for the first time.
- Caryolane-type sesquiterpenes were isolated from the genus Cirsium for the first time.