Pinus halepensis essential oil attenuates the toxic Alzheimer's amyloid beta (1-42)-induced memory impairment and oxidative stress in the rat hippocampus.

The most prevalent neurodegenerative disease is Alzheimer's dementia. It is determined by the deposits of amyloid-beta peptide which leads to memory impairment, oxidative stress, and neurodegeneration. Aromatherapy by using essential oils could represent a natural treatment option for Alzheimer's dementia. Therefore, this study aimed to identify the neuroprotective and nootropic effects of Pinus halepensis essential oil (PNO, 1% and 3%, administered for three weeks) in a rat model of acute amyloid beta (1-42) (Aβ1-42) toxicity. Rats were behaviorally tested (radial arm maze and Y-maze activities being used). Rats were divided into five groups (n = 5 / group): first group - vehicle, second group - Aβ1-42, the third and fourth group - PNO treatment groups (1% and 3%), and fifth group - donepezil group (as positive control, 5 mg/kg injected in Aβ1-42-treated rats). Antioxidant activity of the investigated essential oil was assessed using radical scavenging assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) tests. Also, biochemical estimations of the brain homogenates for acetylcholinesterase and oxidative stress biomarkers were carried out. The essential oil reversed the amyloid beta (1-42)-induced decreasing of the spontaneous alternation in the Y-maze test and the amyloid beta (1-42)-induced increasing of the working and reference memory errors in the radial arm maze test. The amyloid beta (1-42)-induced modification of the balance oxidant-antioxidant and acetylcholinesterase action in the hippocampus of the rat has been ameliorated using the essential oil. These findings suggested that Pinus halepensis essential oil has nootropic and neuroprotective activities and may be regarded as a therapeutic tool for attenuation of Aβ toxicity and neuronal dysfunction.