Chemical Profiling, Anticholinesterase Inhibitory Activity and Molecular Docking Studies of Essential Oil from Calophyllum canum Hook.f. ex T.Anderson

Medicinal plant essential oils are an important source of bioactive compounds with potential relevance to neurodegenerative disorders, including Alzheimer's disease.In this study, the chemical composition and anticholinesterase activity of the essential oil obtained from Calophyllum canum leaves collected in Malaysia were investigated.Gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analyses identified eleven constituents, representing 99.6% of the total oil composition.The oil was dominated by caryophyllene oxide (41.7%), spathulenol (31.8%), γ-eudesmol (6.0%), and βeudesmol (5.8%).Anticholinesterase activity was assessed using Ellman's method.A moderate inhibitory effect was observed for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes with IC50 values of 88.5 ± 0.22 and 92.2 ± 0.21 μg/mL, respectively.Molecular docking of the two major constituents alongside galantamine (reference inhibitor) showed favorable binding interactions toward AChE and BChE, with predicted binding energies of -5.5 to -7.6 kcal/mol for the plant constituents and -8.5/-8.0kcal/mol (AChE/BChE) for galantamine, supporting their accommodation within the enzyme active sites.This study provides the first report on the chemical profile and anticholinesterase potential of C. canum essential oil, highlighting its promise as a natural source of neuroactive compounds and contributing to the pharmacological characterization of the Calophyllum genus.