A beta-secretase (BACE1) inhibitor hispidin from the mycelial cultures of Phellinus linteus.

In the course of screening for anti-dementia agents from natural products, a beta-secretase (BACE1) inhibitor was isolated from the culture broth of Phellinus linteus and identified as hispidin. It showed an IC (50) value of 4.9 x 10 (-6) M and a Ki value of 8.4 x 10 (-6) M. The compound was a non-competitive inhibitor. Hispidin also inhibited a prolyl endopeptidase (IC (50) = 1.6 x 10 (-5) M, Ki = 2.4 x 10 (-5) M), but it was less inhibitory to alpha-secretase (TACE) and other serine proteases such as chymotrypsin, trypsin, and elastase.