Nano-delivery systems for encapsulation of dietary polyphenols: An experimental approach for neurodegenerative diseases and brain tumors.

Neurodegenerative diseases (NDs) and brain tumors are severe, disabling, and incurable disorders that represent a critical problem regarding human suffering and the economic burden on the healthcare system. Because of the lack of effective therapies to treat NDs and brain tumors, the challenge for physicians is to discover new drugs to improve their patients' quality of life. In addition to risk factors such as genetics and environmental influences, increased cellular oxidative stress has been reported as one of the potential common etiologies in both disorders. Given their antioxidant and anti-inflammatory potential, dietary polyphenols are considered to be one of the most bioactive natural agents in chronic disease prevention and treatment. Despite the protective activity of polyphenols, their inefficient delivery systems and poor bioavailability strongly limit their use in medicine and functional food. A potential solution lies in polymeric nanoparticle-based polyphenol delivery systems that are able to enhance their absorption across the gastrointestinal tract, improve their bioavailability, and transport them to target organs. In the present manuscript, we provide an overview of the primary polyphenols used for ND and brain tumor prevention and treatment by focusing on recent findings, the principal factors limiting their application in clinical practice, and a promising delivery strategy to improve their bioavailability.