Acetylcholinesterase inhibitory activity of chemical constituents isolated from Miliusa thorelii

Two new dihydrooxoprotoberberine alkaloids; miliusathorines A (1) and B (2), a new natural flavone, miliusathorone (3), together with twenty-two known compounds (4-25) were isolated from the combined stem and root extract and the leaf extract of Miliusa thorelii. The structures of all isolated compounds were elucidated by spectroscopic methods and mass spectrometry. All compounds were evaluated for their acetylcholinesterase activities. Miliusathorine A (1) and norushisunine had the best AChE inhibitory activities, however these were weak inhibitors when compared to the standard galantamine.