Acetylcholinesterase and butyrylcholinesterase inhibitory compounds from Corydalis cava Schweigg. & Kort

In the course of screening plants used in Danish folk medicine as memory enhancers, a crude methanolic extract of tubers from Corydalis cava showed significant acetylcholinesterase inhibitory activity in a dose-dependent manner. Activity guided fractionation of the methanolic extract resulted in the isolation of three alkaloids, bulbocapnine (1), corydaline (2) and corydine (3) as active constituents. Bulbocapnine inhibited acetylcholinesterase as well as butyrylcholinesterase in a dose-dependent manner with IC50 values of 40 ± 2 μM and 83 ± 3 μM, respectively. Corydaline inhibited acetylcholinesterase in a dose-dependent manner with an IC50 value of 15 ± 3 μM and corydine inhibited butyrylcholinesterase in a dose-dependent manner with an IC50 value of 52 ± 4 μM. Corydaline was considered inactive against butyrylcholinesterase and corydine against acetylcholinesterase, due to IC50 > 100 μM.