Anti-BACE1 and anti-AchE activities of undescribed spiro-dioxolane-containing meroterpenoids from the endophytic fungus Aspergillus terreus Thom

Abstract Spiroterreusnoids A–F, six undescribed spiro-dioxolane-containing adducts bearing 3,5-dimethylorsellinic acid-based meroterpenoid and 2,3-butanediol moieties were isolated from the endophytic fungus Aspergillus terreus Thom from Tripterygium wilfordii Hook. f. (Celastraceae). The structures of these adducts were established by spectroscopy, single-crystal X-ray diffraction, and experimental electronic circular dichroism (ECD) measurements. Spiroterreusnoids A–F represent the first examples of adducts composed of 3,5-dimethylorsellinic acid-based meroterpenoids. It is noteworthy that spiroterreusnoids A–F possessing a spiro-dioxolane moiety exhibited potential abilities in inhibiting BACE1 (IC 50 values ranging from 5.86 to 27.16  μ M) and AchE (IC 50 values ranging from 22.18 to 32.51  μ M), while the other analogues without this fragment displayed no such activities. Taken together, spiroterreusnoids A–F represent the first multitargeted natural adducts that could inhibit BACE1 and AchE, and might provide a new template for the development of new anti-Alzheimer's disease drugs.