beta-secretase inhibitory effects of furanocoumarins from the root of Angelica dahurica.

In the course of screening antidementia agents from natural products, five beta-secretase (BACE1) inhibitors were isolated from the root extract of Angelica dahurica (Umbelliferae). They were identified as furanocoumarins, isoimperatorin (1), imperatorin (2), (+)-oxypeucedanin (3), (+)-byakangelicol (4) and (+)-byakangelicin (5). Among them, compounds 2 and 4 showed significant inhibitory activity against beta-secretase (BACE1) with IC(50) values of 91.8 +/- 7.5 and 104.9 +/- 2.4 microM, respectively. Compounds 1-5 inhibited BACE1 activity in a dose-dependent manner.