Proaporphine and aporphine alkaloids with acetylcholinesterase inhibitory activity from Stephania epigaea

摘要

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 Stephanie epigaea. The absolute configuration of 1 was determined by calculating electronic circular dichroism (ECD) and comparing with experimental data. Compounds 2 and 4 showed strong acetylcholinesterase (AChE) inhibitory effects with the IC50 values of 436 and 2.98 mu M, respectively. Compounds 5-9 also exhibited potent AChE inhibitory activities. (C) 2015 Elsevier B.V. All rights reserved.