A new benzyldihydroisoquinoline alkaloid (1) was isolated from the tubers of Corydalis cava and named corylucinine. Additionally, 8-trichloromethyl-7,8- dihydropalmatine (2), an isolation artifact of tetrahydropalmatine, was obtained. The structures were established by spectroscopic (including 2D NMR and optical rotation) and HR-ESI-MS methods. Both compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. In comparison with the used standards, both compounds showed only moderate inhibitory activity against HuAChE (IC 50, HuAChE = 127.6 ± 5.2 μM for 1, and IC 50, HuAChE = 82.9 ± 3.9 μM for 2 ) and none against HuBuChE.