Multifunctional tacrine-trolox hybrids for the treatment of Alzheimer's disease with cholinergic, antioxidant, neuroprotective and hepatoprotective properties.

Combining tacrine with trolox in a single molecule, novel multifunctional hybrids have been designed and synthesized. All these hybrids showed ChE inhibitory activity in nanomolar range and strong antioxidant activity close to the parent compound trolox. Among them, compound 6d was the most potent inhibitor against AChE (IC50 value of 9.8 nM for eeAChE and 23.5 nM for hAChE), and it was also a strong inhibitor to BuChE (IC50 value of 22.2 nM for eqBuChE and 20.5 nM for hBuChE). Molecular modeling and kinetic studies suggested that 6d was a mixed-type inhibitor, binding simultaneously to CAS and PAS of AChE. In vivo hepatotoxicity assays indicated that 6d was much less toxic than tacrine. In addition, it showed neuroprotective effect and good ability to penetrate the BBB. Overall, all these results highlighted 6d a promising multifunctional agent for AD treatment.