The (R)-enantiomer of alkannin is known as shikonin, and the racemic mixture of the two is known as shikalkin.
Shikonin is a naphthoquinone derivative primarily isolated from the roots of plants in the Boraginaceae family (e.g., Lithospermum erythrorhizon).
Shikonin is the main active component of a Chinese medicinal plant 'Zi Cao'
-Shikonin is a major component of zicao (purple gromwell, the dried root of Lithospermum erythrorhizon), a Chinese herbal medicine with anti-inflammatory properties
-Quinone methides (QMs) are highly reactive intermediates formed from natural compounds like shikonin
-ic50 cancer cells 1-10uM, normal cells >10uM
-known as Glycolysis inhibitor: ( inhibit pyruvate kinase M2 (PKM2*******), a key enzyme in the glycolytic pathway)
Available from mcsformulas.com
Shikonin Pro Liposomal, 30 mg
Also In Glycolysis Inhibithree(100 mg PHLORIZIN,10 mg TANSHINONE IIA, 8 mg Shikonin)
-Note half-life15-30mins or 8hr?.
BioAv low, poor water solubility
Pathways:
- usually induce
ROS production in cancer cells, and reduce ROS in normal cells.
- ROS↑ related:
MMP↓(ΔΨm),
ER Stress↑,
GRP78↑,
Ca+2↑,
Cyt‑c↑,
Caspases↑,
DNA damage↑,
cl-PARP↑,
HSP↓,
- Lowers AntiOxidant defense in Cancer Cells:
NRF2↓,
TrxR↓**,
SOD↓,
GSH↓
Catalase↓
GPx4↓
- Raises
AntiOxidant
defense in Normal Cells:
ROS↓,
NRF2↑,
SOD↑,
GSH↑,
Catalase↑,
- lowers
Inflammation :
NF-kB↓">NF-kB↓,
COX2↓,
p38↓, Pro-Inflammatory Cytokines :
NLRP3↓,
IL-1β↓,
TNF-α↓,
IL-6↓,
IL-8↓
- inhibit Growth/Metastases :
TumMeta↓,
TumCG↓,
EMT↓,
MMPs↓,
MMP2↓,
MMP9↓,
IGF-1↓,
uPA↓,
VEGF↓,
FAK↓,
NF-κB↓,
TGF-β↓,
ERK↓
- cause Cell cycle arrest :
TumCCA↑,
cyclin D1↓,
cyclin E↓,
CDK2↓,
CDK4↓,
- inhibits Migration/Invasion :
TumCMig↓,
TumCI↓,
FAK↓,
ERK↓,
EMT↓,
- inhibits
glycolysis
/Warburg Effect and
ATP depletion :
HIF-1α↓,
PKM2↓,
cMyc↓,
GLUT1↓,
LDH↓,
LDHA↓,
HK2↓,
PFKs↓,
PDKs↓,
ECAR↓,
OXPHOS↓,
GRP78↑,
GlucoseCon↓
- inhibits
angiogenesis↓ :
VEGF↓,
HIF-1α↓,
EGFR↓,
Integrins↓,
- Others: PI3K↓,
AKT↓,
JAK↓,
STAT↓,
β-catenin↓,
AMPK,
ERK↓,
JNK,
P53↑,
- Synergies:
chemo-sensitization,
chemoProtective,
RadioSensitizer,
Others(review target notes),
Neuroprotective,
Cognitive,
Renoprotection,
Hepatoprotective,
CardioProtective,
- Selectivity:
Cancer Cells vs Normal Cells
| Rank |
Pathway / Target Axis |
Direction |
Primary Effect |
Notes / Cancer Relevance |
| 1 |
PKM2-mediated aerobic glycolysis (Warburg metabolism) |
↓ |
Energy / biomass restriction |
Key, repeatedly reported mechanism: shikonin suppresses PKM2 activity and PKM2-driven glycolysis in multiple tumor models, with downstream growth inhibition and apoptosis |
| 2 |
ROS accumulation / oxidative stress |
↑ ROS |
Redox overload |
Common upstream trigger that drives mitochondrial dysfunction and regulated cell death programs; often precedes necroptosis/apoptosis signaling |
| 3 |
Necroptosis core cascade (RIPK1 → RIPK3 → MLKL) |
↑ |
Programmed necrotic cell death |
Strong evidence across cancers (e.g., leukemia and nasopharyngeal carcinoma): shikonin increases RIPK1/RIPK3/MLKL expression/activation; necroptosis inhibitors can blunt the effect |
| 4 |
Mitochondrial integrity (ΔΨm) |
↓ |
Mitochondrial dysfunction |
ROS-linked depolarization; acts as a pivot into intrinsic apoptosis and other death programs |
| 5 |
Intrinsic apoptosis (BAX/BAK → Caspase-9/3) |
↑ |
Programmed cell death |
Frequently observed; often framed as ROS → mitochondrial damage → caspase-dependent apoptosis |
| 6 |
PKM2/STAT3 signaling axis |
↓ |
Reduced survival & proliferation signaling |
In ESCC and related models, shikonin suppresses PKM2-driven glycolysis and down-modulates STAT3 pathway activity |
| 7 |
NF-κB pathway |
↓ |
Reduced pro-survival transcription |
Reported as part of multi-target suppression of inflammatory/anti-apoptotic programs in several tumor models and reviews |
| 8 |
PI3K–AKT (± mTOR) |
↓ |
Growth & resistance pathway inhibition |
Often described as sensitizing cells to apoptosis/TRAIL; may be secondary to oxidative stress and metabolic collapse |
| 9 |
Stress MAPKs (JNK / p38) |
↑ |
Pro-death stress signaling |
Common downstream response to ROS; can reinforce apoptosis and other death outcomes |
| 10 |
Ferroptosis-related axis (lipid peroxidation; GPX4) |
↑ lipid perox / ↓ GPX4 |
Iron-dependent oxidative death |
Reported prominently for acetylshikonin (a shikonin derivative): ROS-associated lipid peroxidation with reduced GPX4 expression alongside RIPK1/RIPK3/MLKL activation |
| 11 |
Endoplasmic reticulum stress (UPR / ERS) |
↑ |
Proteotoxic stress signaling |
Frequently mentioned in leukemia-focused mechanism summaries and broader reviews as contributory to growth arrest and death |
| 12 |
Multiple regulated death programs (apoptosis / necroptosis / ferroptosis / pyroptosis) |
↑ (context-dependent) |
Broader cell-death engagement |
Recent reviews emphasize that shikonin can engage several programmed cell death modalities depending on cell context and dosing |
| Rank |
Pathway / Target Axis |
Direction |
Primary Effect |
Notes / Cancer Relevance |
Ref |
| 1 |
PKM2-mediated aerobic glycolysis (Warburg metabolism) |
↓ PKM2 activity / ↓ glycolysis |
Energy & biomass restriction |
Demonstrates shikonin (and analogs) inhibit cancer glycolysis, reducing glucose consumption/lactate production via PKM2 targeting |
(ref) |
| 2 |
PKM2 → STAT3 signaling axis |
↓ PKM2-driven signaling / ↓ STAT3 pathway |
Reduced survival & proliferation |
ESCC study: shikonin suppresses PKM2-mediated aerobic glycolysis and regulates PKM2/STAT3 signaling |
(ref) |
| 3 |
Necroptosis (RIPK1 → RIPK3 → MLKL) |
↑ RIPK1/RIPK3/MLKL |
Programmed necrotic cell death |
Nasopharyngeal carcinoma: shikonin induces necroptosis with upregulation of RIPK1/RIPK3/MLKL (with ROS involvement) |
(ref) |
| 4 |
ROS accumulation |
↑ ROS |
Oxidative stress trigger |
Colon cancer model: shikonin increases intracellular ROS; ROS functions upstream of apoptosis |
(ref) |
| 5 |
Mitochondrial apoptosis (Caspase-9/3) |
↑ Caspase-9/3 |
Programmed cell death |
Same colon cancer study shows shikonin increases caspase-3 and caspase-9 activity (mitochondria-mediated apoptosis) |
(ref) |
| 6 |
ER stress / UPR (PERK → eIF2α → CHOP) |
↑ |
Proteotoxic stress apoptosis signaling |
Colon cancer: shikonin-induced apoptosis mediated by PERK/eIF2α/CHOP ER-stress pathway |
(ref) |
| 7 |
Autophagic flux (autophagosome–lysosome completion) |
↓ autophagic flux (blocked) |
ROS + apoptosis amplification |
Colorectal cancer: shikonin induces ROS and apoptosis by inhibiting autophagic flux |
(ref) |
| 8 |
NF-κB signaling |
↓ NF-κB activity |
Reduced pro-survival transcription |
Pancreatic cancer xenograft/mechanistic study: shikonin suppresses NF-κB activity and NF-κB–regulated gene products |
(ref) |
| 9 |
PI3K–AKT–mTOR (stemness / chemoresistance axis) |
↓ PI3K/AKT/mTOR |
Reduced survival & stemness |
Chemoresistant lung cancer CSC context: shikonin attenuates PI3K–Akt–mTOR pathway and reduces cancer stemness |
(ref) |
| 10 |
Cell cycle control (p21; G2/M arrest) |
↑ p21 / ↑ G2/M arrest |
Proliferation block |
Gastric cancer (AGS): shikonin induces cell-cycle arrest linked to p21 regulation |
(ref) |
| 11 |
Invasion / metastasis programs (NF-κB-linked) |
↓ invasion |
Anti-invasive phenotype |
Reports shikonin inhibits tumor invasion via down-regulation of NF-κB–related mechanisms in a high-metastatic tumor model |
(ref) |
| 12 |
Chemosensitization via glycolysis suppression |
↓ glycolysis / ↑ cisplatin sensitivity |
Combination benefit |
NSCLC: shikonin inhibits glycolysis and sensitizes cells to cisplatin (explicitly connecting metabolic suppression to chemosensitization) |
(ref) |
|