Polyphenols and Neuroprotection in Neurodegenerative Disorders

Polyphenols are a diverse class of plant‐derived compounds that have emerged as promising agents to delay or attenuate the progression of neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. Their multifaceted mechanisms include scavenging reactive oxygen species, chelating redox‐active metals, modulating neuroinflammatory signalling, and promoting endogenous antioxidant defences. Certain polyphenols can influence synaptic plasticity and neurogenesis, regulate mitochondrial function, and cross the blood–brain barrier to reach neural tissue. Increasing evidence suggests that gut microbial metabolism of dietary polyphenols yields bioactive metabolites that further contribute to central nervous system homeostasis. Challenges remain in optimising bioavailability, defining effective dosages, and understanding individual variability. Nonetheless, well designed combinations of flavonoids, phenolic acids and stilbenes hold promise both for preventative dietary strategies and as adjuvants to conventional therapies. This field continues to evolve, with translational studies assessing safety, pharmacokinetics and functional outcomes in ageing populations, thereby underscoring global significance and practical applications.

Research from Nature Portfolio

Recent studies have provided compelling evidence that small phenolic metabolites derived from dietary polyphenols traverse the endothelial monolayer of the blood–brain barrier. In vitro and in silico analyses revealed differential transport rates linked to structural features of phenolic sulfates, and endothelial metabolism produced novel derivatives with further bioactivity. Pre‐conditioning of neural cell models with these metabolites conferred resilience against oxidative insult, excitotoxicity and inflammatory stimuli. Mechanistic investigations demonstrated attenuation of microglia‐mediated inflammation via modulation of the NF-κB signalling pathway, thereby supporting a direct neuroprotective role for diet‐derived phenolic compounds in the context of neurodegeneration.

Polyphenols and Neuroprotection in Neurodegenerative Disorders publication trend

The graph below shows the total number of articles in polyphenols and neuroprotection in neurodegenerative disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Blood–brain barrier (BBB): Selective endothelial interface regulating entry of substances into the central nervous system.

Polyphenols: Diverse group of plant‐derived molecules containing multiple phenolic rings, exhibiting antioxidant, anti‐inflammatory and metal‐chelating properties.

Flavonoids: A class of polyphenolic compounds characterised by a C6–C3–C6 backbone, known for radical‐scavenging and signalling‐modulatory actions.

Neuroinflammation: Activation of glial cells and release of pro‐inflammatory mediators within neural tissue.

Oxidative stress: Imbalance between reactive oxygen species production and antioxidant defence leading to molecular and cellular damage.

Microglia: Resident immune cells of the central nervous system responsible for surveillance and inflammatory responses.

References

1. Designing multi-target-directed flavonoids: a strategic approach to Alzheimer's disease. Chemical Science (2023).
2. Dietary Polyphenols as a Protection against Cognitive Decline: Evidence from Animal Experiments; Mechanisms and Limitations. Antioxidants (2023).
3. The Combined Effect of Green Tea, Saffron, Resveratrol, and Citicoline against Neurodegeneration Induced by Oxidative Stress in an In Vitro Model of Cognitive Decline. Oxidative Medicine and Cellular Longevity (2024).
4. Polyphenols journey through blood-brain barrier towards neuronal protection. Scientific Reports (2017).