Harpertrioate A, an A,B,D--Limonoid with Promising Biological Activity against Alzheimer's Disease from Twigs of (Blanco) Merr.

Harpertrioate A (), an A,B,D--limonoid with a rearranged ring B incorporating exocyclic C-30, was isolated from the EtOAc extract of twigs. Its structure, including absolute configurations, was determined on the basis of spectroscopic data and X-ray crystallography. This compound exhibited biological activities against Alzheimer's disease by reducing Aβ42 and Aβ40 production and shifting APP processing toward nonamyloidogenic pathway. The effect of on the Aβ production was comparable to that of gemfibrozil.