Nuclear Factor Erythroid 2-Related Factor 2 (NRF2) is a master transcription factor regulating expression of approximately 300 genes involved in antioxidant defense, detoxification, mitochondrial biogenesis, and anti-inflammatory responses. NRF2 is activated by electrophilic stress and hormetic signals.
Under basal conditions, NRF2 is sequestered in cytoplasm by KEAP1 (Kelch-like ECH-associated protein 1) and targeted for proteasomal degradation. Oxidative stress, electrophilic compounds, or xenobiotics modify KEAP1 cysteine residues, releasing NRF2 to translocate to nucleus and bind antioxidant response elements (ARE). This induces expression of glutathione synthesis enzymes (GCLC, GCLM), phase II detoxification enzymes (GSTs, NQO1), heme oxygenase-1 (HO-1), and mitochondrial proteins. NRF2 activation follows hormetic dose-response—low-dose stressors activate it, but chronic high-dose oxidative stress can overwhelm the system.
NRF2 is the primary hormetic pathway targeted by phytochemicals (polyphenols, isothiocyanates, curcumin). However, continuous NRF2 activation leads to adaptation and downregulation, explaining why single antioxidant supplements or continuous use of one phytochemical becomes ineffective. Rotation of plant-based interventions prevents adaptation while maintaining hormetic benefits.
- Regulates approximately 300 genes involved in cytoprotection
- Activated by cruciferous vegetables (sulforaphane), curcumin, resveratrol, EGCG, quercetin
- Induces glutathione synthesis (GCLC, GCLM genes)
- Upregulates phase II detoxification enzymes (GST, NQO1, UGT)
- Promotes mitochondrial biogenesis and function
- Chronic activation leads to compensatory downregulation—requires cycling
- Involved in longevity research and healthspan extension
- Dysregulation implicated in cancer (can promote tumor survival if constitutively active)
- All active plant substances converge on NRF2 pathway
- glutathione — NRF2 upregulates glutathione synthesis enzymes (GCLC, GCLM)
- hormesis — NRF2 is the primary molecular mechanism of hormetic adaptation
- polyphenols — Plant polyphenols activate NRF2 via KEAP1 modification
- curcumin — Potent NRF2 activator through electrophilic modification of KEAP1
- sulforaphane — Isothiocyanate from cruciferous vegetables, strong NRF2 inducer
- quercetin — Flavonoid activating NRF2 and providing antioxidant effects
- EGCG — Green tea catechin activating NRF2 pathway
- mitochondrial biogenesis — NRF2 promotes mitochondrial biogenesis via PGC-1α interaction
- oxidative stress — Mild oxidative stress activates NRF2; severe stress overwhelms it
- inflammation — NRF2 suppresses NF-κB and reduces inflammatory gene expression
- NF-κB — NRF2 and NF-κB are reciprocally regulated—NRF2 inhibits inflammation
- detoxification — NRF2 induces phase II detoxification enzymes
- aging — NRF2 activity declines with age; activation associated with longevity
- cancer — Dual role—protective in prevention, but constitutive activation promotes tumor survival
- gut barrier — NRF2 protects intestinal epithelium from oxidative damage
- HO-1 — Heme oxygenase-1 is a key NRF2 target gene with anti-inflammatory effects
- KEAP1 — Cytoplasmic repressor of NRF2; modified by electrophiles to release NRF2
- exercise — Exercise-induced ROS transiently activates NRF2
- fasting — Fasting activates NRF2 as part of metabolic stress response
- microbiome — Microbial metabolites (like urolithins) can activate NRF2