Proliferacorins A-M: Thirteen undescribed acorane sesquiterpenoids isolated from the fungus Fusarium proliferatum.

In this study, 13 previously undescribed acorane sesquiterpenoids, namely, proliferacorins A-M, were isolated from the solid fermentation of Fusarium proliferatum. Their structures and absolute configurations were confirmed via spectroscopic analyses, quantum-chemical NMR calculations with DP4+ probability analyses, ECD calculations and comparisons, and single-crystal X-ray diffraction techniques. Proliferacorins A-E (1-5) have a 7-oxa-tricyclo[6.3.1.01,5 ]tridecane decorated with a rare ether bridge between C-7 and C-11, while proliferacorin F (6) possesses a 7-oxa-tricyclic[6.4.0.01,5 ]dodecane skeleton with an unusual ether bond between C-6 and C-11. Proliferacorins C and D (3 and 4) are a pair of isomers at the carbon bridge between C-5 and C-7, whereas proliferacorins H and I (8 and 9) are a pair of spiro carbon isomers. All isolates were tested for their cytotoxic, anti-inflammatory, and immunosuppressive activities.