Abstract

Objectives
The J ordanian ‘M elissa’, (A loysia citrodora ) has been poorly studied both pharmacologically and in the clinic. Essential oils (EO ) derived from leaves of A . citrodora were obtained by hydrodistillation, analysed by gas chromatography‐mass spectrometry (GC‐MS ) and were investigated for a range of neurobiological and pharmacological properties, as a basis for potential future use in drug discovery.

Methods
A selection of central nervous system (CNS) receptor‐binding profiles was carried out. Antioxidant activity and ferrous iron‐chelating assays were adopted, and the neuroprotective properties of A . citrodora  EO assessed using hydrogen peroxide‐induced and β‐amyloid‐induced neurotoxicity with the CAD (C ath.‐a‐differentiated) neuroblastoma cell line.

Key findings
The major chemical components detected in the A . citrodora  EO s, derived from dried and fresh leaves, included limonene, geranial, neral, 1, 8‐cineole, curcumene, spathulenol and caryophyllene oxide, respectively. A . citrodora leaf EO inhibited [3H ] nicotine binding to well washed rat forebrain membranes, and increased iron‐chelation in vitro . A . citrodora  EO displays effective antioxidant, radical‐scavenging activities and significant protective properties vs both hydrogen peroxide‐ and β‐amyloid‐induced neurotoxicity.

Conclusions
A . citrodora  EO displays a range of pharmacological properties worthy of further investigation to isolate the compounds responsible for the observed neuroactivities, to further analyse their mode of action and determine their clinical potential in neurodegenerative diseases.