Tier 3 — preclinical

Dietary flavonoid fisetin regulates aluminium chloride-induced neuronal apoptosis in cortex and hippocampus of mice brain

Prakash D, Sudhandiran G

The Journal of Nutritional Biochemistry 2015 26(12):1527-39

Bibliography

DOI: 10.1016/j.jnutbio.2015.07.017
PubMed: PMID 26411262
Funding: Not explicitly stated in the reviewed sections of the accepted manuscript; study conducted at the Cell Biology Laboratory, Department of Biochemistry, University of Madras.
Competing interests: Not stated in the reviewed sections.

Study snapshot

Design	Randomised controlled animal study. Five groups: vehicle control; AlCl3 alone (200 mg/kg/day, 8 weeks, oral); fisetin pre-treatment (15 mg/kg, 4 weeks before AlCl3) plus co-treatment during AlCl3 exposure; and fisetin-alone control. Endpoints measured by immunohistochemistry (amyloid-beta, cytochrome c, caspase-9, caspase-3, p53), immunofluorescence (p-JNK, ASK-1), RT-PCR (Bax, Bcl-2, cytochrome c mRNA), TUNEL and fluoro-jade C staining for neurodegeneration.
Model	Male Swiss albino mice, oral AlCl3-induced neurotoxicity model targeting cortex and hippocampus.
Sample	5 experimental groups; institutional ethics approval IAEC No. 01/083/09. Per-group animal count not stated in the reviewed sections.
Intervention	Fisetin 15 mg/kg b.wt. orally, 4 weeks pre-treatment then continued for 8 weeks concurrent with AlCl3 (200 mg/kg/day) induction.
Duration	12 weeks total (4-week fisetin pre-treatment + 8-week concurrent AlCl3/fisetin exposure).
Endpoints	Amyloid-beta (Aβ40-42) aggregation (immunohistochemistry); ASK-1 and phospho-JNK expression (immunofluorescence); p53, cytochrome c, caspase-9 and caspase-3 protein expression (immunohistochemistry); Bax/Bcl-2 mRNA ratio (RT-PCR); TUNEL-positive and fluoro-jade C-positive cell counts (neurodegeneration markers)

What the study showed, in plain terms

Aluminium exposure is one of several environmental factors linked to neurodegeneration, and this study asked whether fisetin could protect mouse brain tissue from aluminium-induced damage.

Researchers at the University of Madras gave mice aluminium chloride for eight weeks to trigger amyloid-beta build-up and neuronal apoptosis in the cortex and hippocampus, with or without fisetin pre-treatment and co-treatment.

Fisetin significantly reduced amyloid-beta aggregation and the apoptosis-signalling proteins ASK-1, phospho-JNK, p53, cytochrome c and caspases 9/3, and shifted the Bax/Bcl-2 balance away from cell death. Markers of neurodegeneration (TUNEL, fluoro-jade C) also dropped.

Bottom line: this is a mouse mechanistic study, not human evidence, but it adds to the case that fisetin can blunt a specific apoptosis pathway (ASK-1/JNK) implicated in Alzheimer's- and Parkinson's-type neurodegeneration.

Key findings

Fisetin (15 mg/kg oral) significantly reduced AlCl3-induced amyloid-beta (Aβ40-42) aggregation and neuronal apoptosis markers (ASK-1, p-JNK, p53, cytochrome c, caspase-9, caspase-3) in mouse cortex and hippocampus, and shifted the Bax/Bcl-2 ratio away from apoptosis, with corresponding reductions in TUNEL-positive and fluoro-jade C-positive neurodegeneration markers.

What this study can and cannot tell us

Rodent-only mechanistic study; no human or higher-primate data. Fisetin dose (15 mg/kg) and AlCl3 dose (200 mg/kg/day, one-quarter of LD50) are model-specific and not directly translatable to human aluminium exposure or supplement dosing. Single-lab result not yet independently replicated in this exact model.