Anticholinesterase and carbonic anhydrase inhibitory activities of natural carnosic acid derivatives: A comprehensive in vitro and in silico study

This study investigates the anticholinesterase (acetylcholinesterase [AChE] and butyrylcholinesterase [BChE]) and carbonic anhydrase (CAI and CAII) inhibitory activities of carnosic acid and its natural derivatives, including carnosol, rosmanol, 7-methoxy-rosmanol, 12-methoxy-carnosic acid, and isorosmanol. Among the tested compounds, rosmanol demonstrated exceptional potency, with IC₅₀ values of 0.73 nM for AChE and 0.75 nM for BChE, significantly outperforming tacrine. Rosmanol also exhibited remarkable inhibition of CA I (IC₅₀ = 0.21 nM), surpassing acetazolamide by over 450-fold, and moderate inhibition of CAII. Molecular docking and molecular mechanics generalized born surface area (MM-GBSA) studies revealed strong binding affinities for rosmanol, with docking scores of -11.757 kcal/mol (AChE) and -11.465 kcal/mol (BChE). The MM-GBSA binding free energy calculations further confirmed stable interactions for CA I (-63.24 kcal/mol) and AChE (-60.09 kcal/mol). Molecular dynamics simulations over 50 ns showed stable enzyme-ligand complexes, particularly for AChE and BChE (root mean square deviation ~1.5 Å), with key residues identified as crucial for stabilization. Other derivatives also displayed significant inhibitory activities, suggesting their potential as secondary leads. The ADMET analysis showed favorable pharmacokinetics and rosmanol emerged as a promising candidate. This comprehensive study highlights rosmanol as a multitarget therapeutic agent with potent anticholinesterase and CA inhibitory properties, offering promise for treating neurodegenerative and metabolic disorders.