Beta-secretase (BACE1) inhibitors from Perilla frutescens var. acuta.

In the course of screening for anti-dementia agents from natural products, two beta-secretase (BACE1) inhibitors were isolated from the methanolic extract of Perilla frutescens var. acuta and identified as luteolin (1) and rosmarinic acid (2) with IC50 values of 5.0 x 10(-7) M and 2.1 x 10(-5) M, respectively. They inhibited BACE1 in a non-competitive manner with a substrate in Dixon plots, suggesting that they might bind to either beta-secretase subsite or to another regulatory site. Kivalues of 1 and 2 were 6.2 x 10(-5) M and 3.9 x 10(-5) M, respectively. They were less inhibitory against other enzymes such as alpha-secretase (TACE), acetylcholine esterase (AchE), chymotrypsin, and elastase, indicating that they were relatively specific inhibitors of BACE1.