Acetylcholinesterase Inhibitory Activity of Ethanol Extract of Cinnamon Bark (Cinnamomum burmannii): In Silico and In Vitro Studies

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by decreased acetylcholine (ACh) levels due to elevated acetylcholinesterase (AChE) activity.This shows the need for effective AChE inhibitors such as Cinnamon bark (Cinnamomum burmannii), which contains bioactive compounds with antioxidant and neuroprotective potential.Therefore, this study aimed to evaluate the phenolic, flavonoid, and tannin contents, alongside antioxidant capacity and AChE inhibitory activity of ethanol extract of cinnamon bark as a candidate for supportive AD therapy using in vitro and in silico methods.Phytochemical contents and antioxidant activity were determined using colorimetric assays, while metabolomic profiling was performed using ultra high performance liquid chromatography-quadrupole-orbitrap-high resolution mass spectrometer.AChE inhibition was assessed in vitro through Ellman's method using donepezil, complemented by molecular docking and ADME prediction.The results showed that ethanol extract had strong antioxidant activity, high phenolic, flavonoid, and tannin contents, and 55 identified metabolites.The extract had strong AChE inhibitory activity, with IC50 value of 1.53 ± 0.02 µg/mL.In silico analysis identified five compounds with high binding affinity toward AChE active site.Caffeoylshikimic acid showed the lowest binding energy (-10.39 kcal/mol) but presented limitations in ADMET properties.However, hydroxycinnamaldehyde (HCA; -7.25 kcal/mol) showed favorable pharmacokinetic characteristics, good bioavailability, low predicted toxicity, and effective interactions with both catalytic and peripheral anionic sites of AChE.These results indicated that cinnamon bark ethanol extract, particularly HCA, represented a promising candidate for further investigation as a natural AChE inhibitor for supportive AD therapy.