Aspergoterpenins A⁻D: Four New Antimicrobial Bisabolane Sesquiterpenoid Derivatives from an Endophytic Fungus Aspergillus versicolor

Aspergoterpenins A⁻D ( ⁻ ), four new bisabolane sesquiterpenoid derivatives, were obtained from the endophytic fungus, , together with eight known compounds ( ⁻ ), and their structures were elucidated by a comprehensive analysis of their NMR (Nuclear Magnetic Resonance), MS (Mass Spectrum) and CD (Circular Dichroism) spectra. Aspergoterpenin A ( ) was the first example with a characteristic ketal bridged-ring part in the degraded natural bisabolane-type sesquiterpene structures. The compounds ⁻ displayed no significant activities against four cancer cell lines (A549, Caski, HepG2 and MCF-7). Further, the antimicrobial activities to sub sp. Carotovora were evaluated, and the results showed that compounds ⁻ displayed antimicrobial activities with MIC values ranging from 15.2 to 85.2 μg/mL.