Phytochemical Characterization and Neuroprotective Potential of Ruta chalepensis Essential Oil via Cholinesterase Inhibition

Neurodegenerative diseases, including Alzheimer's disease, are an increasing global health issue, with cholinesterase inhibition serving as an important therapeutic approach to improve cholinergic neurotransmission. The current study aims to examine the chemical composition and cholinesterase inhibitory ability of the essential oil isolated from the aerial parts of Ruta chalepensis. . The anticholinesterase activity of the essential oil was evaluated using a colorimetric assay against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at concentrations of 200, 100, 50, 12.5, and 6.25 μg/mL, with galantamine serving as the positive control. The essential oil was extracted using a hydro-distillation and analyzed by gas chromatography–mass spectrometry, identifying twenty-six components that comprised 92.99% of the total oil content. Ketones constituted the primary chemical class (43.45%), with 2-nonanone (34.20%) being the principal component. Fatty acids, aldehydes, and monoterpenes were identified. The evaluated essential oil exhibited moderate inhibitory effects relative to galantamine (reference drug), with IC₅₀ values of 47.71 ± 0.95 µg/mL (p<0.0001) for AChE and 56.28 ± 1.92 µg/mL (p<0.0001) for BChE. The findings indicate that Ruta chalepensis essential oil contains bioactive compounds with potential anticholinesterase activity, requiring an in vivo investigation for future therapeutic applications in neurological disorders such as Alzheimer's disease.