Targeting microbiota-gut-brain axis with phytochemicals: a mechanistic roadmap for dementia

Area of Science:

• Neuroscience
• Microbiology
• Pharmacology

Background:

• Dementia is a major global health issue with few treatments.
• The gut microbiota significantly influences brain function via the gut-brain axis (GBA).
• Gut microbes are implicated in the pathophysiology of neurological disorders, including dementia.

Purpose of the Study:

• To review the role and application of phytochemicals in dementia treatment by modulating the GBA.
• To explore the link between dementia, microbial dysbiosis, and GBA pathways.
• To highlight the potential of phytochemicals and synergistic approaches for dementia therapy.

Main Methods:

• Literature review focusing on phytochemicals, gut microbiota, and dementia.
• Analysis of mechanisms including tryptophan metabolism, SCFA synthesis, BBB integrity, and microglial activation.
• Examination of phytochemicals like flavonoids, alkaloids, terpenoids, and polyphenols.
• Inclusion of studies on specific compounds (berberine, resveratrol, curcumin) and probiotic/prebiotic strategies.

Main Results:

• Phytochemicals may enhance neuroprotection, restore microbial balance, and regulate inflammatory signaling.
• Specific compounds and synergistic approaches show potential in preclinical and clinical models.
• Dysbiosis in dementia involves altered metabolism, BBB disruption, and neuroinflammation.
• Phytochemicals can influence pathways like BDNF-CREB and inflammatory signaling (NF-κb, Nrf2, MAPK, TLR4).

Conclusions:

• Phytochemicals offer promising therapeutic potential for dementia by targeting the GBA.
• Further research is needed to overcome challenges like bioavailability and standardization.
• Precision nutrition and microbiome-targeted therapies represent future directions for dementia treatment.