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 IC