Reactive oxygen species (ROS), produced during metabolism or following environmental exposure to toxic molecules, are known to have both beneficial and harmful effects depending on their dose. Low ROS doses generated during physiological processes have signalling functions, however higher ones (often associated with lesser antioxidant defences) lead to oxidative stress, which contributes to a number of patho-physiological events including aging and neurodegenerative disorders. The brain, likely owing to its high oxygen requirements, seems to be more susceptible to peroxidation and the neurodegenerative diseases associated with oxidative stress onset compared with other organs.

There is a growing research interest in natural molecules exhibiting preventive and protective abilities for neurodegenerative diseases and aging. As the population is becomes older, and these pathologies increase in coming years, additional efforts are needed to find new strategies and novel substances able to prevent neurodegeneration or to improve the quality of life of elderly people. A great number of natural molecules demonstrate the ability to reduce the accumulation of damage and delay the onset of age-related disorders including neurodegenerative ones. However, the main concern for these molecules is their low bioavailability and absorption rate that negatively affects their pharmacological properties. Current strategies to increase the bioavailability of natural products are based on the improvement of gut microbiota activity leading to the production of functional metabolites with pharmacological effects. Other strategies are based on the development of carrier systems aimed at increasing the bioavailability of natural molecules and their efficacy in the target site.

The aim of this Special Issue is to collect original research and review articles underlying recent progress on natural molecules as modulators in aging and neurodegenerative diseases. We welcome submissions that explore aspects of the therapeutic potential of natural compounds, including those reporting antioxidant effects of novel natural molecules, the mechanisms involved in their anti-aging or neuroprotective activity, and recently discovered delivery methods aimed at improving their efficacy by increasing bioavailability.

Potential topics include but are not limited to the following:

• Antioxidant properties of natural molecules in brain
• Molecular and cellular mechanisms of action of natural molecules
• Natural molecules in prevention of the onset of neurodegeneration
• Crosstalk of natural molecules with gut microbiota and brain
• New delivery methods for improvement of natural molecule bioavailability
• Natural molecules and mitochondrial homeostasis in aging and neurodegeneration
• Healing effects of natural molecules on neuroinflammation