Tacripyrines, the First Tacrine-Dihydropyridine Hybrids, as Multitarget-Directed Ligands for the Treatment of Alzheimer's Disease

Tacripyrines (1-14) have been designed by combining an ACNE inhibitor (tacrine) with a calcium antagonist such as nimodipine and are targeted to develop a multitarget therapeutic strategy to confront AD. Tacripyrines are selective and potent ACNE inhibitors in the nanomolar range. The mixed type inhibition of hAChE activity of compound 11 (IC50 105 +/- 15 nM) is associated to a 30.7 +/- 8.6% inhibition of the proaggregating action of ACNE on the A beta and a moderate inhibition of A beta self-aggregation (34.9 +/- 5.4%). Molecular modeling indicates that binding of compound 11 to the ACNE PAS mainly involves the (R)-11 enantiomer, which also agrees with the noncompetitive inhibition mechanism exhibited by p-methoxytacripyrine 11. Tacripyrines are neuroprotective agents, show moderate Ca2+ channel blocking effect, and cross the blood-brain barrier, emerging as lead candidates for treating AD.