# Linalool vs linalool-loaded chitosan nanoparticles in an Aβ-induced rat model of Alzheimer’s disease: A molecular, biochemical, histological, and behavioral study

## TL;DR

This study compares linalool and linalool-loaded chitosan nanoparticles in a rat model of Alzheimer's, showing that the nanoparticle form is more effective in reducing disease markers.

## Contribution

The study demonstrates that encapsulating linalool in chitosan nanoparticles enhances its therapeutic potential in Alzheimer’s disease models.

## Key findings

- Both linalool and nano-linalool reduced oxidative stress and neuroinflammation in the hippocampus.
- Nano-linalool was more effective than linalool in reducing amyloid plaque deposition and neuronal death.
- Nano-linalool improved learning and spatial memory more significantly than linalool.

## Abstract

Recent studies have increasingly focused on applying nanotechnology to treat neurodegenerative diseases. In this study, we compared the effects of the monoterpene linalool and linalool-loaded chitosan nanoparticles on key pathological features of Alzheimer’s disease (AD), including oxidative stress, neuroinflammation, neuronal death, amyloid plaque deposition, alterations in tryptophan metabolism, and memory deficit in a rat model of AD.

An intracerebroventricular injection of Aβ42 (10 µg) was used to induce the AD model. Linalool (25 mg/kg) and nano-linalool (25 mg/kg) were administered orally once daily for 30 consecutive days.

Both linalool and nano-linalool significantly reduced malondialdehyde levels and enhanced superoxide dismutase activity in the hippocampus. They also decreased the mRNA levels of monocyte chemoattractant protein-1, inhibited the up-regulation of beta-secretase, reduced amyloid plaque deposition, and attenuated pyramidal neuron death in the CA1 region. Additionally, treatment with both compounds down-regulated indoleamine 2,3-dioxygenase, lowered kynurenine levels, and increased serotonin concentrations in the hippocampus. Although both treatments improved learning and spatial memory in Aβ-injected rats, nano-linalool’s effectiveness was more significant than that of linalool in modulating the molecular, biochemical, and histological parameters.

Encapsulating linalool in chitosan nanoparticles enhances its effectiveness in improving molecular, biochemical, and histological changes in the hippocampus of rat models of AD.