Juglone / NRF2 Cancer Research Results

JG, Juglone: Click to Expand ⟱
Features:
Found in roots, leaves, nut-hulls, bark and wood of walnut trees.
Juglone (5-hydroxy-1,4-naphthoquinone)
Juglans nigra refers to the black walnut tree, which is one of the most well-known sources of juglone
-Research has focused on the hulls (the green outer covering of the walnut) because they have the highest concentrations.
-Fresh hulls can contain juglone levels in the range of approximately 1–5% of the dry weight

-Juglone can redox cycle to generate reactive oxygen species (ROS).
-Increasing Bax, decreasing Bcl‑2, caspase activation, and MMP depolarization.
-Modulation of MAPK pathways (including ERK, JNK, and p38)
-May inhibit NF‑κB signaling
-Cause DNA damage or stress that, in turn, leads to p53 pathway activation— Pin1 Inhibition
–Pin1, a peptidyl-prolyl cis/trans isomerase, is frequently overexpressed in cancer.

-ic50 maybe 5-10uM
-For matching 5uM, crude estimate is 5mg consumption of juglone required which might be 1.5 g of black walnut hull material

Juglone — Juglone (5-hydroxy-1,4-naphthoquinone; JG) is a naturally occurring redox-active naphthoquinone found in plants of the Juglans genus, including black walnut (Juglans nigra), with particularly high concentrations reported in green walnut hulls. It is best classified as a natural small-molecule quinone and experimental anticancer agent rather than an established therapeutic drug. Its anticancer activity is strongly concentration-dependent and reflects electrophilic thiol reactivity, redox cycling, oxidative stress, mitochondrial injury, ferroptosis, apoptosis, and modulation of several oncogenic signaling pathways. Juglone is also widely used experimentally as a Pin1 inhibitor, although this designation should not imply high target selectivity because juglone can covalently modify protein sulfhydryl groups and affect transcription and other cellular proteins.

Primary mechanisms (ranked):

  1. Quinone redox cycling and electrophilic thiol reactivity causing ↑ ROS, ↓ glutathione-dependent antioxidant capacity, oxidative macromolecular injury, and oxidative-stress-driven cell death.
  2. Ferroptosis induction through lipid peroxidation and disruption of antioxidant defenses, including ↓ GPX4 and, in some cancer models, ↓ NRF2 signaling or activation of the FOSL1-HMOX1 axis.
  3. Mitochondrial apoptosis through ↓ mitochondrial membrane potential, ↑ Bax/Bcl-2 ratio, cytochrome-c release, and caspase activation.
  4. Pin1 inhibition contributing to suppression of proliferation, cancer-cell stemness, EMT, migration, angiogenesis, and oncogenic signaling; however, juglone is not a highly selective Pin1 pharmacological probe.
  5. Suppression of PI3K-AKT and related survival signaling, frequently downstream of or amplified by oxidative stress.
  6. Cell-cycle arrest through modulation of cyclins, CDKs, p21, p27, p53, and related checkpoint pathways.
  7. Stress-MAPK modulation, particularly ↑ p38 and ↑ JNK, contributing to apoptosis, ferroptosis, and autophagic responses.
  8. Suppression of EMT, invasion, stem-like phenotype, Wnt/β-catenin signaling, HIF-1α, VEGF, and angiogenic/metastatic programs in selected cancer models.
  9. Autophagy induction as a context-dependent stress response that can interact with apoptosis and oxidative injury.

Bioavailability / PK relevance: Free juglone has unfavorable drug-delivery characteristics, including hydrophobicity, high chemical reactivity, rapid disposition, and substantial renal exposure. In an animal intravenous PK study, free juglone had a plasma half-life of approximately 2 hours and showed prominent kidney localization; sterically stabilized liposomal delivery increased plasma half-life approximately 12-fold, improved tumor localization, and reduced renal toxicity. Robust human oral pharmacokinetic data are lacking. Consequently, dietary or walnut-hull intake cannot presently be converted reliably into a systemic micromolar juglone exposure.

In-vitro vs systemic exposure relevance: Most direct anticancer studies use approximately low-to-tens-of-micromolar juglone, commonly around 5–20 µM. Whether these free-drug concentrations can be maintained safely in human tumors is not established. Recent quantitative work also demonstrates limited intracellular accumulation despite extracellular juglone exposure. Thus, common in-vitro concentrations should not be assumed to be achievable through oral walnut or black-walnut-hull consumption.

Clinical evidence status: Preclinical. Juglone has substantial cell-culture evidence and multiple mouse/xenograft studies showing antitumor activity, including apoptosis, ferroptosis, anti-metastatic, and anti-angiogenic effects. There is no established anticancer dose, regulatory approval, or convincing human clinical efficacy evidence for juglone itself. Translation is limited by nonspecific electrophilic/redox chemistry, systemic toxicity risk, formulation and pharmacokinetic limitations, and the uncertain therapeutic window between cancer and normal tissues.

Juglone Mechanistic Profile

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 Quinone redox cycling and thiol reactivity ↑ ROS; ↑ oxidative stress; ↓ cellular thiol buffering ↑ oxidative injury possible P/R Oxidative-stress overload Central upstream mechanism. Juglone participates in redox cycling and can react with protein and glutathione sulfhydryl groups; this contributes to efficacy but also limits selectivity.
2 Glutathione and antioxidant defense ↓ GSH; ↓ GPX4; ↓ SOD (model-dependent) ↓ antioxidant reserve possible (dose-dependent) R Loss of redox buffering Creates a permissive environment for ROS accumulation, lipid oxidation, apoptosis, and ferroptosis.
3 Ferroptosis and lipid peroxidation ↑ ferroptosis; ↑ lipid peroxidation; ↑ MDA; ↑ labile iron Potential ferroptotic toxicity at sufficient exposure R/G Iron-dependent oxidative cell death Strong recent evidence in hepatocellular carcinoma and glioblastoma; pathway execution is cancer-type dependent.
4 NRF2 GPX4 antioxidant axis ↓ NRF2; ↓ GPX4 (model-dependent) Not established R/G Ferroptosis sensitization Demonstrated particularly in glioblastoma. NRF2 modulation should not be generalized to every tumor model.
5 FOSL1 HMOX1 ferroptosis axis ↑ FOSL1; ↑ HMOX1 Not established G Ferroptosis amplification Recent HCC and pan-cancer evidence identifies this transcriptional axis as an important juglone-responsive ferroptotic mechanism.
6 Mitochondrial membrane integrity ↓ membrane potential; ↑ cytochrome-c release Mitochondrial toxicity possible R Intrinsic apoptosis initiation Observed across breast, gastric, prostate, and other cancer models.
7 BAX BCL2 caspase apoptosis ↑ BAX; ↓ BCL2; ↑ caspase-3/7; ↑ caspase-8/9 Apoptosis possible at cytotoxic exposure R/G Programmed cell death Both intrinsic and extrinsic apoptotic pathways can participate. Recent colorectal cancer data support activation of caspase-8 as well as mitochondrial caspase-9 signaling.
8 Pin1 prolyl isomerase ↓ Pin1 activity/function ↓ Pin1 and other thiol-sensitive proteins possible P/R Reduced oncogenic signaling and stemness Important experimental target associated with ↓ proliferation, ↓ EMT, ↓ stemness, and ↓ angiogenesis. Juglone is not Pin1-selective and can directly modify sulfhydryl-containing proteins.
9 PI3K AKT survival signaling ↓ PI3K; ↓ AKT; ↓ p-AKT Context-dependent R/G Survival pathway suppression ROS scavenging can partially reverse this effect in NSCLC, indicating substantial coupling between oxidative stress and PI3K-AKT inhibition.
10 p38 JNK stress signaling ↑ p38; ↑ JNK Context-dependent R Stress-mediated apoptosis and ferroptosis Activation is frequently associated with ROS production and can contribute to NRF2-GPX4 suppression and programmed cell death.
11 Cell cycle checkpoints ↑ arrest; ↓ CDK2; ↓ CDK4; ↓ cyclins; ↑ p21; ↑ p27 Growth inhibition possible G Proliferation blockade Cell-cycle phase varies by model. Recent colorectal cancer data support G0/G1 arrest with suppression of CCND1, CCNB1, CDK2, and CDK4.
12 p53 DNA damage response ↑ DNA damage; ↑ γH2AX; ↑ p53 (model-dependent) Genotoxicity possible R/G Checkpoint activation and apoptosis May arise partly from quinone-driven ROS and electrophilic stress rather than a specific DNA-targeting interaction.
13 Intracellular calcium and mitochondrial stress ↑ Ca²⁺ (model-dependent) Not established P/R Apoptotic signaling Increased intracellular Ca²⁺ has been demonstrated in MCF-7 cells together with ROS elevation and mitochondrial depolarization.
14 EMT migration and invasion ↓ EMT; ↑ E-cadherin; ↓ N-cadherin; ↓ Snail; ↓ migration; ↓ invasion Not established G Reduced metastatic phenotype Pin1, AKT-GSK3β-Snail, TGF-β-related, and other signaling systems have been implicated depending on tumor model.
15 Cancer stemness ↓ sphere formation; ↓ tumor-initiating phenotype Not established G Reduced self-renewal and metastatic potential Pin1 inhibition appears to contribute. Effects have been demonstrated in colorectal and other tumor-initiating cell models.
16 Wnt beta-catenin signaling ↓ Wnt/β-catenin (model-dependent) Not established G Reduced invasion and angiogenesis Most clearly demonstrated in pancreatic cancer models; not necessarily a universal primary mechanism.
17 HIF-1α VEGF angiogenic signaling ↓ HIF-1α; ↓ VEGF; ↓ angiogenesis Potential vascular effects not well characterized G Reduced tumor vascular support Secondary/contextual anticancer mechanism reported in pancreatic cancer and Pin1-related models.
18 Autophagy stress response ↑ LC3-II; ↑ Beclin-1; ↓ p62 (model-dependent) Context-dependent G Autophagic stress and death crosstalk Autophagy can accompany ROS/MAPK signaling but its contribution to net cytotoxicity varies by cell type and experimental conditions.
19 Chemosensitization ↑ drug cytotoxicity in selected combinations Potential ↑ combination toxicity G Combination-treatment sensitization Juglone can enhance etoposide cytotoxicity through Pin1-related mechanisms, but sequence of administration can substantially alter the interaction.
20 Clinical Translation Constraint Effective concentrations commonly ~5–20 µM in vitro Systemic electrophilic and oxidative toxicity limits selectivity G Uncertain therapeutic window Human bioavailability and therapeutic exposure are not established. Free juglone has short animal plasma persistence, renal accumulation, and nephrotoxicity; formulations such as liposomes materially alter PK and distribution.

P: 0–30 min     R: 30 min–3 hr     G: >3 hr

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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⟱
5099- JG,    Juglone induces ferroptosis in glioblastoma cells by inhibiting the Nrf2-GPX4 axis through the phosphorylation of p38MAPK
- vitro+vivo, GBM, LN229 - vitro+vivo, GBM, T98G
Ferroptosis↑, p‑MAPK↑, NRF2↓, GPx4↓, TumPF↓, Apoptosis↑, ROS↑, GSH↓, lipid-P↑, Ki-67↓, TumCG↓,

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(tgid=1) ⓘ

Ferroptosis↑, 1,   GPx4↓, 1,   GSH↓, 1,   lipid-P↑, 1,   NRF2↓, 1,   ROS↑, 1,  

Cell Death(tgid=5) ⓘ

Apoptosis↑, 1,   Ferroptosis↑, 1,   p‑MAPK↑, 1,  

Proliferation, Differentiation & Cell State(tgid=12) ⓘ

TumCG↓, 1,  

Migration(tgid=13) ⓘ

Ki-67↓, 1,   TumPF↓, 1,  

Clinical Biomarkers(tgid=22) ⓘ

Ki-67↓, 1,  
Total Targets: 13

Pathway results for Effect on Normal Cells:


Total Targets: 0

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#:105  Target#:226  State#:%  Dir#:1
  wNotes=0  sortOrder:rid,rpid

 

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