Alkaloids with acetylcholinesterase inhibitory activity from Corydalis racemosa (Thunb.) Pers

Two new isoquinoline alkaloids (1 and 2) along with fourteen known alkaloids (3–16) were isolated from Corydalis racemosa (Thunb.) Pers. Their structures were elucidated by analyzing spectroscopic and spectrometric data (NMR, UV, IR, and MS) and comparing their spectroscopic, spectrometric and physicochemical data with the values archived in the literature. The absolute configurations of new compounds were determined via X-ray crystallographic assay and electronic circular dichroism calculations. Acetylcholinesterase (AChE) inhibitory activity of all compounds was evaluated. Compounds 5, 6, 9, 11, and 12 exhibited inhibitory activity against AChE with IC₅₀ values ranged from 10.2 to 63.4 μM.