Essential Oil Molecules Can Break the Loop of Oxidative Stress in Neurodegenerative Diseases.

Simple Summary: Neurodegenerative diseases (NDs) affect millions of people worldwide. The combination of genes and environment, associated with age, contributes to the risk of developing one of these diseases. NDs occur when neurons in the brain and in the peripheral nervous system lose function over time and ultimately die in some area of the brain. The mechanism of neuronal deaths is specific for each ND and may involve different nervous cell types, but always includes excessive oxidative stress and increased inflammatory responses. Although certain drugs may help relieve some of the physical or mental ND symptoms, sometimes slowing down their progression, no cure exists. This mini review focuses on the possibility to explore the efficacy of selected promising essential oil molecules to effectively counteract the oxidation and inflammation that occurs in NDs. Essential oils (EOs) are mixtures of volatile compounds, extracted from aromatic plants, with multiple activities including antioxidant and anti-inflammatory ones. EOs are complex mixtures easy to find on the market and with low costs. In this mini narrative review, we have collected the results of in vitro and in vivo studies, which tested these EOs on validated models of neurodegeneration and in particular of the two main neurodegenerative diseases (NDs) that afflict humans: Alzheimer's and Parkinson's. Since EO compositions can vary greatly, depending on the environmental conditions, plant cultivar, and extraction methods, we focused our attention to studies involving single EO molecules, and in particular those that have demonstrated the ability to cross the blood–brain barrier. These single EO molecules, alone or in defined mixtures, could be interesting new therapies to prevent or slow down oxidative and inflammatory processes which are common mechanisms that contribute to neuronal death in all NDs. [ABSTRACT FROM AUTHOR]