Acetylcholinesterase (AChE) is distributed throughout the body in both neuronal and non-neuronal tissues and plays an important role in the regulation of physiological events. Caffeic acid is a phenolic compound that has anti-inflammatory and neuroprotective properties. The aim of this study was to investigate in vitro and in vivo whether caffeic acid alters the AChE activity and behavioral parameters in rats. In the in vitro study, the concentrations of 0, 0.1, 0.5, 1.0, 1.5, and 2 mM of caffeic acid were used. For the in vivo study, five groups were evaluated: group I (control); group II (canola oil), group III (10 mg/kg of caffeic acid); group IV (50 mg/kg of caffeic acid) and group V (100 mg/kg of caffeic acid). Caffeic acid was diluted in canola oil and administered for 30 days. In vitro, the caffeic acid increased the AChE activity in the cerebral cortex, cerebellum, hypothalamus, whole blood, and lymphocytes at different concentrations. In muscle, this compound caused an inhibition in the AChE activity at concentrations of 0.5, 1.0, 1.5, and 2 mM when compared to the control (P < 0.05). In vivo, 50 and 100 mg/kg of caffeic acid decreased the AChE activity in the cerebral cortex and striatum and increased the activity of this enzyme in the cerebellum, hippocampus, hypothalamus, pons, lymphocytes, and muscles when compared to the control group (P < 0.05). The amount of 100 mg/kg of caffeic acid improved the step-down latencies in the inhibitory avoidance. Our results demonstrated that caffeic acid improved memory and interfered with the cholinergic signaling. As a natural and promising compound caffeic acid should be considered potentially therapeutic in disorders that involve the cholinergic system.Highlights
▸ Caffeic acid increased the AChE activity in brain and lymphocytes in vitro. ▸ In muscle, caffeic acid caused an inhibition in the AChE activity in vitro. ▸ Caffeic acid (10, 50, and 100 mg/kg) decreased the AChE activity in cortex and striatum. ▸ Caffeic acid (10, 50, and 100 mg/kg) increased the AChE activity in hippocampus. ▸ Caffeic acid at 100 mg/kg improved the step-down latencies in inhibitory avoidance.