Acetylcholinesterase inhibitors from the roots of Angelica dahurica.

In the course of finding Korean natural products for acetylcholinesterase (AChE) inhibitory activity, we found that a methanolic extract of the roots of Angelica dahurica showed significant inhibitory effects on AChE. Bioassay-guided fractionation of the methanolic extract resulted in the isolation of three furanocoumarins, isoimperatorin (1), imperatorin (2) and oxypeucedanin (3), as active principles. These compounds inhibited AChE activity in a dose-dependent manner, and the IC50 values of compounds 1-3 were 74.6, 63.7 and 89.1 microM, respectively.