METHODS AND RESULTS: An unusual proaporphine alkaloid bearing an isopropanenitrile group at isoquinoline nitrogen, named epiganine A (1) and a new aporphine alkaloid, epiganine B (2), together with eight known alkaloids, pronuciferine (3), dehydrodicentrine (4), romerine (5), romeline (6), N-methylcalycinine (7), phanostenine (8), dicentrine (9), and N-methyllaurotetanine (10), were isolated from the roots of Stephania epigaea. The absolute configuration of 1 was determined by calculating electronic circular dichroism (ECD) and comparing with experimental data.
CONCLUSIONS:
Compounds 2 and 4 showed strong acetylcholinesterase (AChE) inhibitory effects with the IC50 values of 4.36 and 2.98μM, respectively. Compounds 5-9 also exhibited potent AChE inhibitory activities. |