Biphenyl-3-oxo-1,2,4-triazine linked piperazine derivatives as potential cholinesterase inhibitors with anti-oxidant property to improve the learning and memory

A series of novel piperazine tethered biphenyl-3-oxo-1,2,4-triazine derivatives were designed, and synthesized. Amongst the synthesized analogs, compound 6g showed significant non-competitive inhibitory potential against acetylcholinesterase (AChE, IC50; 0.2 +/- 0.01 mu M) compared to standard donepezil (AChE, IC50: 0.1 +/- 0.002 mu M). Compound 6g also exhibited significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE (22.22 +/- 1.11%) and showed good CNS permeability in PAMPA-BBB assay (P-e(exp) , 6.93 +/- 0.46). The in vivo behavioral studies of compound 6g indicated significant improvement in cognitive dysfunctions against scopolamine-induced amnesia mouse models. Further, ex vivo studies showed a significant AChE inhibition and reversal of the scopolamine-induced oxidative stress by compound 6g. Moreover, molecular docking and dynamics simulations of compound 6g showed a consensual binding affinity and active site interactions with the PAS and active catalytic site (CAS) residues of AChE.