Norfriedelins A–C with Acetylcholinesterase Inhibitory Activity from Acerola Tree (Malpighia emarginata)

Abstract

Three novel norfriedelanes, A-C (1-3), were isolated from the branches and roots of Malpighia emarginata . Their structures and absolute configurations were determined by 1D and 2D NMR techniques and X-ray crystallographic analysis. Norfriedelin A (possessing an α-oxo-β-lactone group) and norfriedelin B (with a keto-lactone group) showed acetylcholinesterase inhibitory effects with the IC50 values of 10.3 and 28.7 μM, respectively.