New barrigenol-type triterpenoids with anti-Alzheimer’s disease activity from Koelreuteria paniculata Laxm.

Abstract Koelreuteria paniculata Laxm. has long been cultivated as a traditional ornamental tree in the world, and is developed as a source of natural green food. In this work, five new barrigenol-type triterpenoids, compounds 1–5, were isolated from the seeds of Koelreuteria paniculata Laxm. and elucidated by right of several spectroscopic methods. We studied the impacts of compounds 1–5 on learning and memory impairment induced by okadaic acid (OA) in mice. Notably, compounds 2 and 5 exhibited great effects in the behavioral experiments. Further, the experiments suggested that compounds 2 and 5 may play a considerable role in regulating the level of glycogen synthase kinase-3β (GSK-3β) and protein phosphatase 2A (PP2A), thereby reducing hyperphosphorylation of tau protein. In addition, the molecular docking studies were performed on compounds 2 and 5 to initially explore possible molecular mechanisms.