Geraniol / HO-1 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.


HO-1, HMOX1: Click to Expand ⟱
Source:
Type:
(Also known as Hsp32 and HMOX1)
HO-1 is the common abbreviation for the protein (heme oxygenase‑1) produced by the HMOX1 gene.
HO-1 is an enzyme that plays a crucial role in various cellular processes, including the breakdown of heme, a toxic molecule. Research has shown that HO-1 is involved in the development and progression of cancer.
-widely regarded as having antioxidant and cytoprotective effects
-The overall activity of HO‑1 helps to reduce the pro‐oxidant load (by degrading free heme, a pro‑oxidant) and to generate molecules (like bilirubin) that can protect cells from oxidative damage

Studies have found that HO-1 is overexpressed in various types of cancer, including lung, breast, colon, and prostate cancer. The overexpression of HO-1 in cancer cells can contribute to their survival and proliferation by:
  Reducing oxidative stress and inflammation
  Promoting angiogenesis (the formation of new blood vessels)
  Inhibiting apoptosis (programmed cell death)
  Enhancing cell migration and invasion
When HO-1 is at a normal level, it mainly exerts an antioxidant effect, and when it is excessively elevated, it causes an accumulation of iron ions.

A proper cellular level of HMOX1 plays an antioxidative function to protect cells from ROS toxicity. However, its overexpression has pro-oxidant effects to induce ferroptosis of cells, which is dependent on intracellular iron accumulation and increased ROS content upon excessive activation of HMOX1.

-Curcumin   Activates the Nrf2 pathway leading to HO‑1 induction; known for its anti‑inflammatory and antioxidant effects.
-Resveratrol  Induces HO‑1 via activation of SIRT1/Nrf2 signaling; exhibits antioxidant and cardioprotective properties.
-Quercetin   Activates Nrf2 and related antioxidant pathways; contributes to anti‑oxidative and anti‑inflammatory responses.
-EGCG     Promotes HO‑1 expression through activation of the Nrf2/ARE pathway; also exhibits anti‑inflammatory and anticancer properties.
-Sulforaphane One of the most potent natural HO‑1 inducers; triggers Nrf2 nuclear translocation and upregulates a battery of phase II detoxifying enzymes.
-Luteolin    Induces HO‑1 via Nrf2 activation; may also exert anti‑inflammatory and neuroprotective effects in various cell models.
-Apigenin   Has been reported to induce HO‑1 expression partly via the MAPK and Nrf2 pathways; also known for anti‑inflammatory and anticancer activities.
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↓,
6573- Ger,    Systematic elucidation of the mechanism of geraniol via network pharmacology
- Study, Nor, NA - Study, Var, NA
HO-1↝, HRAS↓, *IL8↓, *AChE↓, NF-kB↓, PCNA↓, BAX↑, Bcl-2↓, P53↑, Casp3↑, Casp8↑, Casp9↑,

Showing Research Papers: 1 to 2 of 2

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 2

Pathway results for Effect on Cancer / Diseased Cells:


Redox & Oxidative Stress ⓘ

HO-1↝, 1,   ROS↓, 1,  

Cell Death ⓘ

Apoptosis↑, 1,   BAX↑, 1,   Bcl-2↓, 1,   Casp↝, 1,   Casp3↑, 1,   Casp8↑, 1,   Casp9↑, 1,  

Autophagy & Lysosomes ⓘ

Beclin-1↓, 1,  

DNA Damage & Repair ⓘ

P53↑, 1,   P53↝, 1,   PCNA↓, 1,  

Cell Cycle & Senescence ⓘ

TumCCA↑, 1,  

Proliferation, Differentiation & Cell State ⓘ

HRAS↓, 1,   STAT3↓, 1,   TumCG↑, 1,  

Migration ⓘ

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

Angiogenesis & Vasculature ⓘ

angioG↓, 1,   Hif1a↓, 1,  

Immune & Inflammatory Signaling ⓘ

NF-kB↓, 1,  

Drug Metabolism & Resistance ⓘ

selectivity↑, 1,  
Total Targets: 24

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,   IL8↓, 1,   Inflam↓, 1,   NF-kB↓, 1,  

Synaptic & Neurotransmission ⓘ

AChE↓, 2,  

Protein Aggregation ⓘ

XO↓, 1,  

Functional Outcomes ⓘ

AntiCan↑, 1,   memory↑, 1,   neuroP↑, 1,  
Total Targets: 23

Scientific Paper Hit Count for: HO-1, HMOX1
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#:597  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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