Selective Pseudo-irreversible Butyrylcholinesterase Inhibitors Transferring Antioxidant Moieties to the Enzyme Show Pronounced Neuroprotective Efficacy In Vitro and In Vivo in an Alzheimer’s Disease Mouse Model

A series
of multitarget-directed ligands (MTDLs) was designed by
functionalizing a pseudo-irreversible butyrylcholinesterase (BChE)
inhibitor. The obtained hybrids were investigated in vitro regarding
their hBChE and hAChE inhibition,
their enzyme kinetics, and their antioxidant physicochemical properties
(DPPH, ORAC, metal chelating). In addition, in vitro assays were applied
to investigate antioxidant effects using murine hippocampal HT22 cells
and immunomodulatory effects on the murine microglial N9 cell line.
The MTDLs retained their antioxidative properties compared to the
parent antioxidant-moieties in vitro and the inhibition of hBChE was maintained in the submicromolar range. Representative
compounds were tested in a pharmacological Alzheimer’s disease
(AD) mouse model and demonstrated very high efficacy at doses as low
as 0.1 mg/kg. The most promising compound was also tested in BChE–/– mice and showed reduced efficacy. In vivo
neuroprotection by BChE inhibition can be effectively enhanced by
incorporation of structurally diverse antioxidant moieties.