# GC-MS-based metabolic profiling of essential oils from Citrus paradisi, Lawsonia inermis, and Ruta graveolens and assessment of their acetylcholinesterase inhibitory potential

## TL;DR

This study analyzed essential oils from grapefruit, henna, and sadab for their chemical composition and ability to inhibit acetylcholinesterase, a target for Alzheimer's disease treatments.

## Contribution

The study provides new insights into the AChE inhibitory potential of essential oils from Citrus paradisi and Lawsonia inermis.

## Key findings

- Grapefruit essential oil showed the strongest AChE inhibition with an IC50 of 12.62 μg/mL.
- Henna essential oil had moderate AChE inhibition with an IC50 of 43.90 μg/mL.
- Sadab essential oil exhibited negligible AChE inhibitory activity.

## Abstract

Plant-derived essential oils (EOs) are rich sources of bioactive compounds, some of which exhibit acetylcholinesterase (AChE) inhibitory activity and may offer therapeutic potential for the management of Alzheimer’s disease (AD). This study aimed to evaluate the chemical composition and AChE inhibitory potential of essential oils extracted from Citrus paradisi (grapefruit), Lawsonia inermis (henna), and Ruta graveolens (sadab).

Essential oils were obtained by hydrodistillation and analyzed using gas chromatography–mass spectrometry (GC–MS) to identify their chemical constituents. AChE inhibitory activity was determined using Ellman’s colorimetric assay, and IC50 values were calculated to assess inhibitory potency.

A total of 63 metabolites were identified across the three essential oils, accounting for approximately 90% of their total composition. Grapefruit EO was predominantly composed of limonene (89.94%), henna EO was rich in phytol (41.42%) and limonene (23.02%), while sadab EO was characterized by 1-hexadecanol acetate (26.39%) and phytol (20.54%). Grapefruit EO exhibited the strongest AChE inhibitory activity (IC50 = 12.62 ± 0.48 μg/mL), followed by henna EO (IC50 = 43.90 ± 0.97 μg/mL), whereas sadab EO showed negligible inhibition.

The notable AChE inhibitory activity observed in grapefruit and henna essential oils is likely attributable to their high terpenoid content. These findings suggest that selected plant-derived essential oils may represent promising natural candidates for the prevention or management of neurodegenerative disorders such as Alzheimer’s disease.