Asperversins A and B, Two Novel Meroterpenoids with an Unusual 5/6/6/6 Ring from the Marine-Derived Fungus Aspergillus versicolor .

Asperversins A ( 1 ) and B ( 2 ), two novel meroterpenoids featuring an uncommon 5/6/6/6 ring system, along with five new analogues ( 3 ⁻ 7 ) and a known compound asperdemin ( 8 ), were obtained from the marine-derived fungus Aspergillus versicolor . Their structures and absolute configurations were confirmed by extensive spectroscopic analyses, single-crystal X-ray diffraction studies, and electronic circular dichroism (ECD) calculation. All new compounds were tested for their acetylcholinesterase enzyme (AChE) inhibitory activities and cytotoxic activities, of which compound 7 displayed moderate inhibitory activity against the AChE with an IC50 value of 13.6 μM.