Description: <p><b>Carnosic acid</b> (CA) is a <b>phenolic diterpene natural product</b> derived primarily from <b>rosemary (Rosmarinus officinalis / Salvia rosmarinus)</b> and sage species.<br>
<b>Primary mechanisms (conceptual rank):</b><br>
1) <b>Electrophilic redox modulation → KEAP1 interaction → NRF2 activation</b> (P→G)<br>
2) <b>Pro-oxidant shift in cancer cells (ROS ↑ beyond threshold)</b> → apoptosis / growth arrest (dose- & context-dependent) (P/R)<br>
3) <b>PI3K/AKT/mTOR and STAT3 pathway suppression</b> (R/G; model-dependent)<br>
<b>Bioavailability / PK:</b> Lipophilic; oral absorption occurs but systemic levels are modest and subject to metabolism (glucuronidation/oxidation). Brain penetration reported in models.<br>
<b>In-vitro vs realistic exposure:</b> Many anti-cancer effects observed at <b>10–50 µM</b> in vitro; achievable human plasma concentrations from dietary rosemary extracts are likely substantially lower.<br>
<b>Clinical evidence status (cancer):</b> Predominantly <b>preclinical</b>; no robust RCT evidence as a stand-alone anti-cancer therapy. More developed as a nutraceutical antioxidant/neuroprotective candidate.</p>
<b>Carnosic acid (CA)</b> natural antioxidant diterpene found in rosemary and sage. <br>
<br>
Pathways:<br>
-Inhibit the PI3K/Akt pathway, which is typically overactivated in many cancers.<br>
-inhibits ERK activation, reducing cell proliferation.<br>
-JNK and p38 MAPK: Activation of these kinases by carnosic acid may contribute to stress responses leading to cell cycle arrest or apoptosis.<br>
-Block the activation of NF-κB,<br>
-Induce apoptosis by disturbing mitochondrial membrane potential, leading to the release of cytochrome c and activation of caspases.<br>
-Dual role: as an antioxidant under normal conditions and, in the context of cancer cells, it can induce ROS production beyond a critical threshold.<br>
-Interfere with STAT3 activation, <br>
-AMPK Activation<br>
-Inhibition of Angiogenesis and Metastasis<br>
-Induction of endoplasmic reticulum (ER) stress<br>
<br>
-At lower concentrations, carnosic acid might exhibit antioxidant activity, protecting cells by scavenging free radicals. However, cancer cells often have altered redox balances which can make them more vulnerable to further ROS increases.<br>
-While carnosic acid has antioxidant properties in some contexts, it is typically observed to have a prooxidant effect in cancer cells under specific conditions, particularly at concentrations that favor ROS accumulation and the subsequent induction of apoptotic cell death<br>
<br>
-10-100uM, or 10–100 mg/kg for achieving anticancer effects.<br>
-Typically available in standardized rosemary extracts.<br>
<br>
<h3>Carnosic Acid (CA) — Pathway / Axis Effects (Cancer vs Normal)</h3>
<table>
<tr>
<th>Rank</th>
<th>Pathway / Axis</th>
<th>Cancer Cells (↑ / ↓ / ↔)</th>
<th>Normal Cells (↑ / ↓ / ↔)</th>
<th>TSF</th>
<th>Primary Effect</th>
<th>Notes / Interpretation</th>
</tr>
<tr>
<td>1</td>
<td><b>NRF2 / KEAP1 axis</b></td>
<td>↔ / ↑ cytoprotection (context-dependent; resistance risk)</td>
<td>↑ antioxidant defense (protective)</td>
<td>P→G</td>
<td>Stress-response activation</td>
<td>Electrophilic quinone form modifies KEAP1 cysteines; protective in normal tissue but may enhance survival in NRF2-driven tumors.</td>
</tr>
<tr>
<td>2</td>
<td><b>ROS</b></td>
<td>↑ ROS (dose-dependent; high concentration) → apoptosis</td>
<td>↓ oxidative damage (low–moderate dose)</td>
<td>P/R</td>
<td>Redox bifunctionality</td>
<td>Acts as antioxidant at low stress; can become pro-oxidant in metabolically stressed cancer cells.</td>
</tr>
<tr>
<td>3</td>
<td><b>PI3K / AKT / mTOR</b></td>
<td>↓ signaling (model-dependent)</td>
<td>↔</td>
<td>R/G</td>
<td>Proliferation suppression</td>
<td>Reported in breast, prostate, leukemia models; downstream cell-cycle arrest.</td>
</tr>
<tr>
<td>4</td>
<td><b>STAT3</b></td>
<td>↓ phosphorylation/activity (model-dependent)</td>
<td>↔</td>
<td>R/G</td>
<td>Growth and survival inhibition</td>
<td>Relevant in inflammation-driven or STAT3-addicted tumors.</td>
</tr>
<tr>
<td>5</td>
<td><b>HIF-1α / Warburg axis</b></td>
<td>↓ HIF-1α (model-dependent)</td>
<td>↔</td>
<td>G</td>
<td>Hypoxia signaling suppression</td>
<td>Reported reduction of glycolytic adaptation under hypoxic conditions in some models.</td>
</tr>
<tr>
<td>6</td>
<td><b>Ca²⁺ (ER stress linkage)</b></td>
<td>↑ ER stress–linked Ca²⁺ signaling (model-dependent)</td>
<td>↔ / protective</td>
<td>P/R</td>
<td>Apoptosis induction (subset)</td>
<td>Often secondary to ROS elevation and mitochondrial perturbation.</td>
</tr>
<tr>
<td>7</td>
<td><b>Ferroptosis</b></td>
<td>↔ / ↑ (model-dependent; lipid ROS context)</td>
<td>↓ lipid peroxidation (low dose)</td>
<td>R/G</td>
<td>Lipid redox modulation</td>
<td>Antioxidant capacity may oppose ferroptosis at low dose; oxidative conversion could promote it under stress.</td>
</tr>
<tr>
<td>8</td>
<td><i>Clinical Translation Constraint</i></td>
<td colspan="2">Most anti-cancer data at 10–50 µM in vitro; systemic exposure from dietary intake likely below these levels. NRF2 activation could theoretically protect tumor cells in certain contexts.</td>
<td>—</td>
<td>PK-limited; preclinical stage</td>
<td>Consider tumor NRF2 status and dose when interpreting translational relevance.</td>
</tr>
</table>
<p><b>TSF legend:</b> P: 0–30 min (primary/rapid effects; direct redox interactions) · R: 30 min–3 hr (acute signaling + stress responses) · G: >3 hr (gene-regulatory adaptation; phenotype outcomes)</p>
<br>
<h3>Carnosic Acid (CA) — Alzheimer’s Disease (AD) / Neuroprotection</h3>
<table>
<tr>
<th>Rank</th>
<th>Pathway / Axis</th>
<th>AD Brain (↑ / ↓ / ↔)</th>
<th>Normal Brain (↑ / ↓ / ↔)</th>
<th>TSF</th>
<th>Primary Effect</th>
<th>Notes / Interpretation</th>
</tr>
<tr>
<td>1</td>
<td><b>NRF2 activation</b></td>
<td>↑ antioxidant gene expression</td>
<td>↑ protective</td>
<td>P→G</td>
<td>Neuroprotection</td>
<td>Well-supported in preclinical models; CA described as a pro-electrophilic NRF2 activator.</td>
</tr>
<tr>
<td>2</td>
<td><b>ROS</b></td>
<td>↓ oxidative stress</td>
<td>↓ oxidative burden</td>
<td>P/R</td>
<td>Mitochondrial protection</td>
<td>Particularly relevant in oxidative neurodegenerative models.</td>
</tr>
<tr>
<td>3</td>
<td><b>Neuroinflammation (NF-κB)</b></td>
<td>↓ inflammatory signaling</td>
<td>↓ inflammatory tone</td>
<td>R/G</td>
<td>Anti-inflammatory</td>
<td>Reported microglial modulation in models.</td>
</tr>
<tr>
<td>4</td>
<td><b>Aβ toxicity modulation</b></td>
<td>↓ Aβ-induced toxicity (model-dependent)</td>
<td>↔</td>
<td>R/G</td>
<td>Neuronal survival support</td>
<td>Preclinical evidence only; no large human RCT confirmation.</td>
</tr>
<tr>
<td>5</td>
<td><i>Clinical Translation Constraint</i></td>
<td colspan="2">Primarily preclinical neuroprotection data; human AD efficacy not yet established in large RCTs.</td>
<td>—</td>
<td>Early translational stage</td>
<td>Mechanistically plausible but clinically unproven.</td>
</tr>
</table>
<p><b>TSF legend:</b> P: 0–30 min · R: 30 min–3 hr · G: >3 hr</p>