Proline-Based Carbamates as Cholinesterase Inhibitors.

Area of Science:

• Medicinal Chemistry
• Neuroscience
• Computational Chemistry

Background:

• Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are key targets for treating neurodegenerative diseases like Alzheimer's.
• Developing selective and non-toxic cholinesterase inhibitors remains a significant challenge in drug discovery.
• Structure-activity relationships of pyrrolidine-based carbamates are not fully understood.

Purpose of the Study:

• To synthesize and characterize a series of novel benzyl (2S)-2-(arylcarbamoyl)pyrrolidine-1-carboxylates.
• To evaluate the in vitro inhibitory activity and selectivity against AChE and BChE.
• To investigate the structure-activity relationships and pharmacophore patterns using in silico methods.

Main Methods:

• Chemical synthesis and characterization of 25 benzyl pyrrolidine carboxylate derivatives.
• In vitro enzyme inhibition assays for AChE and BChE.
• Cytotoxicity screening using a human monocytic leukemia THP-1 cell line.
• In silico analysis including Comparative Molecular Surface Analysis (CoMSA), Principal Component Analysis (PCA), and molecular docking.

Main Results:

• All synthesized compounds exhibited low cytotoxicity.
• Moderate inhibitory effects against AChE were observed, with benzyl (2S)-2-[(2-chlorophenyl)carbamoyl]pyrrolidine-1-carboxylate being the most potent (IC50 = 46.35 μM).
• Benzyl (2S)-2-[(4-bromophenyl)]- and benzyl (2S)-2-[(2-bromophenyl)carbamoyl]pyrrolidine-1-carboxylates showed significant anti-BChE activity (IC50 = 28.21 and 27.38 μM), comparable to rivastigmine.
• Ortho-brominated and ortho-hydroxyphenyl derivatives demonstrated higher selectivity for BChE.
• In silico studies identified key structural and physicochemical features influencing inhibitory potency and selectivity.

Conclusions:

• The synthesized benzyl pyrrolidine carboxylates are non-toxic and possess moderate AChE inhibitory and notable BChE inhibitory activities.
• Specific structural modifications, particularly ortho-bromination and ortho-hydroxylation on the phenyl ring, enhance BChE selectivity.
• The study provides valuable insights into the structure-activity relationships for designing potent and selective cholinesterase inhibitors.