Syntheses and characterization of novel oxoisoaporphine derivatives as dual inhibitors for cholinesterases and amyloid beta aggregation

A series of 3-substituted (5c-5f, 6c-6f) and 4-substituted (10a-10g) oxoisoaporphine derivatives were synthesized. It was found that all these synthetic compounds had IC(50) values at micro or nano molar range for cholinesterase inhibition, and most of them could inhibit amyloid beta (A beta) self-induced aggregation with inhibition ratio from 31.8% to 57.6%. The structure activity relationship studies revealed that the derivatives with higher selectivity on AChE also showed better inhibition on A beta self-induced aggregation. The results from cell toxicity study indicated that most quaternary methiodide salts had higher IC(50) values than the corresponding non-quaternary compounds. This study provided potentially important information for further development of oxoisoaporphine derivatives as lead compounds for the treatment of Alzheimer's disease. (C) 2011 Elsevier Masson SAS. All rights reserved.