Geraniol / NRF2 Cancer Research Results

Ger, Geraniol: Click to Expand ⟱
Features:

Geraniol — an acyclic monoterpene alcohol and fragrance compound found in citronella, palmarosa, rose, lemongrass, rose-geranium, and several other essential oils. It is formally classified as a plant-derived monoterpenoid natural product; Citronella oil is not equivalent to geraniol: it is a variable multi-component essential oil distilled primarily from Cymbopogon winterianus or Cymbopogon nardus, with citronellal, geraniol, citronellol, geranyl acetate, limonene, and other terpenes as principal constituents.

Primary mechanisms (ranked):

  1. Induction of intrinsic and caspase-dependent apoptosis through mitochondrial dysfunction, altered BAX/BCL-2 balance, cytochrome-c release, and caspase activation.
  2. Suppression of PI3K/AKT/mTOR survival and growth signalling.
  3. Disruption of mevalonate and lipid metabolism, including inhibition of HMG-CoA reductase activity and reduced availability of intermediates required for membrane synthesis and protein prenylation.
  4. Suppression of NF-κB, inflammatory cytokine, MAPK, and JAK/STAT3 signalling in responsive cancer models.
  5. Cell-cycle arrest and inhibition of DNA synthesis, proliferation, migration, invasion, and epithelial–mesenchymal transition.
  6. Chemosensitization, particularly enhancement of 5-fluorouracil activity in colorectal-cancer models.
  7. Redox modulation, with pro-oxidant mitochondrial stress reported in some cancer models but antioxidant and NRF2-associated cytoprotection reported in non-cancer and injury models; direction is strongly context-dependent.

Bioavailability / PK relevance: Geraniol is lipophilic and can be absorbed after oral administration, but it is rapidly distributed and extensively converted to geranic acid, dihydrogeranic acid, glucuronide conjugates, and other metabolites. Rat studies indicate a short blood half-life and large formulation-dependent differences in oral bioavailability. Recent mouse studies likewise show rapid metabolism, so free-geraniol exposure is transient. Emulsions, lipid carriers, nanoformulations, and encapsulation may increase exposure, but these delivery systems do not establish clinical anticancer efficacy. Citronella-oil composition and exposure vary substantially with species, chemotype, cultivation, storage, and formulation.

In-vitro vs systemic exposure relevance: Many anticancer experiments use geraniol concentrations in the tens to hundreds of micromolar range, and some use still higher levels. These sustained concentrations may exceed free systemic concentrations achievable through ordinary dietary or flavouring exposure because geraniol is rapidly metabolized and cleared. Direct comparison is difficult because human plasma PK data for therapeutic dosing are limited. Cytotoxic findings from undiluted or concentrated citronella oil should not be attributed solely to geraniol because citronellal, citronellol, methyl isoeugenol, limonene, and minor constituents may contribute independently or interact.

Clinical evidence status: Preclinical. Evidence consists primarily of cancer-cell studies, chemically induced animal-tumour models, and xenograft studies. Geraniol has shown enhancement of 5-fluorouracil in colorectal-cancer models, but there are no established randomized controlled trials demonstrating that isolated oral or systemic geraniol treats cancer. A clinical study of a multi-ingredient topical essential-oil formulation for HPV-related disease cannot establish geraniol-specific efficacy. Neither geraniol nor citronella oil is an approved anticancer treatment or validated oncology adjunct.

Safety / regulatory relevance: Geraniol is widely used as a flavouring and fragrance ingredient, while citronella oil is also used as a flavouring and insect-repellent ingredient. Food-use safety evaluations do not establish safety at pharmacological anticancer doses. Geraniol is a recognized fragrance allergen and can cause allergic contact dermatitis, particularly after oxidation. Concentrated citronella oil can irritate skin, eyes, mucosa, and the gastrointestinal tract and should not be treated as interchangeable with food-grade geraniol. Citronella oil also contains composition-dependent constituents, including methyl isoeugenol in some preparations, that require separate toxicological consideration.

Geraniol Cancer Mechanisms

Rank Pathway / Axis Cancer Cells Normal Cells Primary Effect Notes / Interpretation
1 Mitochondrial apoptosis ↑ BAX/BCL-2 ratio; ↑ cytochrome-c release; ↑ caspase-9 and caspase-3; ↓ mitochondrial membrane potential ↔ or ↓ apoptotic injury in some oxidative-stress models (context-dependent) Apoptosis and reduced tumour-cell survival One of the most consistently reported endpoints, but effective concentrations and upstream triggers vary by cell line.
2 PI3K AKT mTOR signalling ↓ PI3K; ↓ phosphorylated AKT; ↓ mTOR and downstream survival signalling ↔ or ↑ AKT-mediated survival in selected injury models (context-dependent) Reduced proliferation, survival, protein synthesis, and treatment resistance Observed in oral, nasopharyngeal, prostate, and other experimental cancer systems; direct molecular binding has not been established consistently.
3 Mevalonate and lipid metabolism ↓ HMG-CoA reductase activity; ↓ mevalonate-pathway flux; altered fatty-acid and phospholipid metabolism ↓ cholesterol synthesis (dose-dependent) Reduced membrane synthesis, proliferation, and potentially protein prenylation Mechanistically important in hepatocarcinoma and chemically induced colorectal-tumour models. Rescue by mevalonate has not been demonstrated uniformly across models.
4 NF-κB inflammatory survival signalling ↓ NF-κB activation; ↓ inflammatory and anti-apoptotic signalling ↓ NF-κB-driven inflammation in several non-cancer models Reduced survival, inflammation, invasion, and apoptosis resistance NF-κB modulation may be downstream of AKT inhibition or redox changes rather than a single direct target.
5 JAK STAT3 signalling ↓ STAT3 activation; ↓ survival and proliferation signals Insufficient evidence Apoptosis and suppression of tumour-promoting transcription Reported in selected thyroid and other cancer-cell models; breadth across tumour types remains uncertain.
6 MAPK stress and proliferation signalling ↓ or altered ERK, JNK, and p38 signalling (model-dependent) ↔ or protective modulation (context-dependent) Cell-cycle arrest, stress signalling, and apoptosis The direction differs by cell type, concentration, and treatment duration; the MAPK family should not be represented as uniformly inhibited.
7 Cell cycle and DNA synthesis ↓ DNA synthesis; ↓ cyclin-associated progression; ↑ cell-cycle arrest Insufficient evidence at comparable exposure Reduced proliferation Cell-cycle phase varies among studies and may reflect secondary effects of metabolic stress or apoptosis.
8 Migration invasion and EMT ↓ migration; ↓ invasion; ↓ mesenchymal phenotype (model-dependent) Insufficient evidence Reduced metastatic behaviour Predominantly in-vitro evidence; clinically relevant anti-metastatic activity has not been demonstrated.
9 Mitochondrial ROS increase ↑ ROS and oxidative stress in some cytotoxic models (dose-dependent) (high concentration only) ↓ oxidative injury in multiple inflammatory or toxic-injury models (context-dependent) Oxidative mitochondrial damage and apoptosis Geraniol is not uniformly pro-oxidant. Redox direction depends on tissue, baseline stress, concentration, and treatment duration.
10 NRF2 antioxidant response ↔ or uncertain; possible cytoprotection in some contexts NRF2-associated antioxidant enzymes in selected injury models Secondary antioxidant and tissue-protective response NRF2 is not a well-established central anticancer mechanism for geraniol. Persistent NRF2 activation could theoretically protect some tumour cells.
11 5-Fluorouracil chemosensitization ↑ response to 5-fluorouracil; ↓ tumour growth in colorectal xenograft models Insufficient selectivity data Enhanced chemotherapy activity Promising preclinical interaction, but human efficacy, optimal scheduling, toxicity, and pharmacokinetic interactions are unknown.
12 Clinical Translation Constraint Rapid metabolism; transient free-geraniol exposure; many studies use high concentrations Fragrance sensitization and irritation; systemic high-dose safety incompletely characterized Limits direct translation of experimental cytotoxicity Formulation strongly affects bioavailability. Citronella oil is a heterogeneous mixture and cannot be dosed or interpreted as purified geraniol.


NRF2, nuclear factor erythroid 2-related factor 2: Click to Expand ⟱
Source: TCGA
Type: Antiapoptotic
Nrf2 is responsible for regulating an extensive panel of antioxidant enzymes involved in the detoxification and elimination of oxidative stress. Thought of as "Master Regulator" of antioxidant response.
-One way to estimate Nrf2 induction is through the expression of NQO1.
NQO1, the most potent inducer:
SFN 0.2 μM,
quercetin (2.5 μM),
curcumin (2.7 μM),
Silymarin (3.6 μM),
tamoxifen (5.9 μM),
genistein (6.2 μM ),
beta-carotene (7.2μM),
lutein (17 μM),
resveratrol (21 μM),
indol-3-carbinol (50 μM),
chlorophyll (250 μM),
alpha-cryptoxanthin (1.8 mM),
and zeaxanthin (2.2 mM)

1. Raising Nrf2 enhances the cell's antioxidant defenses and ↓ROS. This strategy is used to decrease chemo-radio side effects.
2. Downregulating Nrf2 lowers antioxidant defenses and ↑ROS. In cancer cells this leads to DNA damage, and cell death.
3. However there are some cases where increasing Nrf2 paradoxically causes an increase in ROS (cancer cells). Such as cases of Mitochondial overload, signal crosstalk, reductive stress

-In some cases, Nrf2 is overexpressed in cancer cells, which can lead to the activation of genes involved in cell proliferation, angiogenesis, and metastasis. This can contribute to the development of resistance to chemotherapy and targeted therapies.
-Increased Nrf2 expression: Lung, Breast, Colorectal, Prostrate.
Decreased Nrf2 expression: Skine, Liver, Pancreatic.
-Nrf2 is a cytoprotective transcription factor which demonstrated both a negative effect as well as a positive effect on cancer
- "promotes Nrf2 translocation from the cytoplasm to the nucleus," means facilitates the movement of Nrf2 into the nucleus, thereby enhancing the cell's antioxidant and cytoprotective responses. -Major regulator of Nrf2 activity in cells is the cytosolic inhibitor Keap1.

Nrf2 Inhibitors and Activators
Nrf2 Inhibitors: Brusatol, Luteolin, Trigonelline, VitC, Retinoic acid, Chrysin
Nrf2 Activators: SFN, OPZ EGCG, Resveratrol, DATS, CUR, CDDO, Api
- potent Nrf2 inducers from plants include sulforaphane, curcumin, EGCG, resveratrol, caffeic acid phenethyl ester, wasabi, cafestol and kahweol (coffee), cinnamon, ginger, garlic, lycopene, rosemany

Nrf2 plays dual roles in that it can protect normal tissues against oxidative damage and can act as an oncogenic protein in tumor tissue.
– In healthy tissues, NRF2 activation helps protect cells from oxidative damage and maintains cellular homeostasis.
– In many cancers, constitutive activation of NRF2 (often through mutations in NRF2 itself or loss-of-function mutations in KEAP1) leads to an enhanced antioxidant capacity.
– This upregulation can promote tumor cell survival by enabling cancer cells to thrive under oxidative stress, resist chemotherapeutic agents, and sustain metabolic reprogramming.
– Elevated NRF2 levels have been implicated in promoting tumor growth, metastasis, and resistance to therapy in various malignancies.
– High or sustained NRF2 activity is frequently associated with aggressive tumor phenotypes, poorer prognosis, and decreased overall survival in several cancer types.
– While its activation is essential for protecting normal cells from oxidative stress, aberrant or sustained NRF2 activation in tumor cells can lead to enhanced survival, therapeutic resistance, and tumor progression.

NRF2 inhibitors: (to decrease antioxidant defenses and increase cell death from ROS).
-Brusatol: most cited natural inhibitors of Nrf2.
-Luteolin: luteolin can reduce Nrf2 activity in specific cancer models and may enhance cell sensitivity to chemotherapy. However, luteolin is also known as an antioxidant, and its influence on Nrf2 can sometimes be context dependent.
-Apigenin: certain studies to down‑regulate Nrf2 in cancer cells: Dose and context dependent .
-Oridonin:
-Wogonin: although its effects might be cell‑ and dose‑specific.
- Withaferin A

Scientific Papers found: Click to Expand⟱
6562- Ger,    Potential Effects of Geraniol on Cancer and Inflammation-Related Diseases: A Review of the Recent Research Findings
- Review, Var, NA - Review, AD, NA
*Inflam↓, *AntiCan↑, *AntiBio↑, *antiOx↑, *neuroP↑, ROS↓, Apoptosis↑, TumCCA↑, P53↝, STAT3↓, Casp↝, *Catalase↑, *GSTs↑, *GPx↑, *AChE↓, *GSH↑, *SOD↑, *TBARS↓, *NO↓, *XO↓, *memory↑, *IL1β↓, *iNOS↓, *NF-kB↓, *COX2↓, *NRF2↑, *HO-1↑, *survivin↓, TumCP↓, TumCMig↓, TumCG↑, selectivity↑, TumMeta↓, angioG↓, Hif1a↓, Beclin-1↓,

Showing Research Papers: 1 to 1 of 1

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 1

Pathway results for Effect on Cancer / Diseased Cells:


Redox & Oxidative Stress

ROS↓, 1,  

Cell Death

Apoptosis↑, 1,   Casp↝, 1,  

Autophagy & Lysosomes

Beclin-1↓, 1,  

DNA Damage & Repair

P53↝, 1,  

Cell Cycle & Senescence

TumCCA↑, 1,  

Proliferation, Differentiation & Cell State

STAT3↓, 1,   TumCG↑, 1,  

Migration

TumCMig↓, 1,   TumCP↓, 1,   TumMeta↓, 1,  

Angiogenesis & Vasculature

angioG↓, 1,   Hif1a↓, 1,  

Drug Metabolism & Resistance

selectivity↑, 1,  
Total Targets: 14

Pathway results for Effect on Normal Cells:


NA, unassigned

AntiBio↑, 1,  

Redox & Oxidative Stress

antiOx↑, 1,   Catalase↑, 1,   GPx↑, 1,   GSH↑, 1,   GSTs↑, 1,   HO-1↑, 1,   NRF2↑, 1,   SOD↑, 1,   TBARS↓, 1,  

Cell Death

iNOS↓, 1,   survivin↓, 1,  

Angiogenesis & Vasculature

NO↓, 1,  

Immune & Inflammatory Signaling

COX2↓, 1,   IL1β↓, 1,   Inflam↓, 1,   NF-kB↓, 1,  

Synaptic & Neurotransmission

AChE↓, 1,  

Protein Aggregation

XO↓, 1,  

Functional Outcomes

AntiCan↑, 1,   memory↑, 1,   neuroP↑, 1,  
Total Targets: 22

Scientific Paper Hit Count for: NRF2, nuclear factor erythroid 2-related factor 2
Query results interpretion may depend on "conditions" listed in the research papers.
Such Conditions may include : 
  -low or high Dose
  -format for product, such as nano of lipid formations
  -different cell line effects
  -synergies with other products 
  -if effect was for normal or cancerous cells
Filter Conditions: Pro/AntiFlg:%  IllCat:%  CanType:%  Cells:%  prod#:414  Target#:226  State#:%  Dir#:%
wNotes=0 sortOrder:rid,rpid

 

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