Daedalols A-C, fungal-derived BACE1 inhibitors.

Bioassay-guided fractionation of an extract prepared from the fruiting bodies of a Daedalea sp. has led to the isolation of daedalols A-C (1-3). The structures of these new triterpenes were elucidated based on extensive NMR spectroscopic and mass spectrometric measurements. Assignment of the relative configuration of 3 required the preparation of a suitable derivative via a Payne rearrangement. The aspartic protease BACE1, an Alzheimer's drug target, was inhibited by 3 with an IC(50) value of 14.2 μM.