Kuwanon U is a potent cholinesterase inhibitor with IC 50 s of 19.69, 10.11 µM and K i s of 6.48, 9.59 µM for acetylcholinesterase ( AChE ) and butyrylcholinesterase ( BChE ), respectively. Kuwanon U has the potential for the research of Alzheimer’s disease (AD).