A novel synthetic derivative of biaryl guanidine as a potential BACE1 inhibitor, to treat Alzheimer's disease: In-silico, in-vitro and in-vivo evaluation.

BACE1 enzyme has been known a potential target involved in Alzheimer's disease (AD). Present research was focused on the principles of virtually screening, chemical synthesis and protease inhibitory effect of BACE1 enzyme via biaryl guanidine derivatives. In-silico based paradigm (ligand binding interaction within active domain of BACE 1 enzyme i.e., aspartate Asp32 and Asp228) a novel compound was synthesized and subsequently subjected to in-vitro and in-vivo evaluation. 1,3-di(isoquinolin-6-yl) guanidine was synthesized and found potent (IC50 6±0.56 µM) and active to arrest (99 %) ß-secretase enzyme (FRET assay). Furthermore, it was found to improve novel object recognition test (RTI =56.55%) and Morris water maze test (32.26±3.45s) significantly (p<0.05). Enhanced pharmacokinetics and related properties (high iLOGP and Log S =-3.98) along with improved permeation to the blood brain barrier (BBB) (zero Lipinski violation) made it feasible to inhibit BACE1 as a novel therapeutic source to treat AD in future.

Biological Evaluation of Newly Synthesized Biaryl Guanidine Derivatives to Arrest ß-Secretase Enzymatic Activity Involved in Alzheimer's Disease.

Proteases BACE1 (ß-secretases) enzymes have been recognized as a promising target associated with Alzheimer's disease (AD). This study was carried out on the principles of molecular docking, chemical synthesis, and enzymatic inhibition of BACE1 enzymes via biaryl guanidine-based ligands. Based on virtual screening, thirteen different compounds were synthesized and subsequently evaluated via in vitro and in vivo studies. Among them, 1,3-bis(5,6-difluoropyridin-3-yl)guanidine (compound (9)) was found the most potent (IC50 = 97 ± 0.91 nM) and active to arrest (99%) ß-secretase enzymes (FRET assay). Furthermore, it was found to improve the novel object recognition test and Morris water maze test significantly (p < 0.05). Improved pharmacokinetic parameters, viz., Log P o/w (1.76), Log S (-2.73), and better penetration to the brain (BBB permeation) with zero Lipinski violation, made it possible to hit the BACE1 as a potential therapeutic source for AD.