Ways to enhance the bioavailability of polyphenols in the brain: A journey through the blood-brain barrier

Bioactive molecules such as polyphenols were identified to play crucial roles in preventing the central nervous system (CNS) diseases. In addition to the poor stability, the blood-brain barrier (BBB), may act as an obstacle for the transport of polyphenols. To improve the bioavailability of polyphenols, nano-encapsulation by polymeric nanoparticles or liposomes was used to improve the bioavailability. Furthermore, to achieve targeted delivery, polyphenols have been conjugated with receptors indirectly to improve the polyphenol delivery through BBB. Roles of polyphenols in preventing CNS disease and the related measures were discussed in this review, which will pave the way for the application of bioactive molecules or drugs in the future.