Silymarin (Milk Thistle) Flowering herb related to daisy and ragweed family.
Silibinin (INN), also known as silybin is the major active constituent of silymarin, a standardized extract of the milk thistle seeds.
-a flavonoid combination of 65–80% of seven flavolignans; the most important of these include silybin, isosilybin, silychristin, isosilychristin, and silydianin. Silybin is the most abundant compound in around 50–70% in isoforms silybin A and silybin B
-Note half-life 6hrs?.
BioAv not soluble in water, low bioAv (1%).
240mg yielded only 0.34ug/ml plasma level. oral administration of SM (equivalent to 120 mg silibinin), total (unconjugated + conjugated) silibinin concentration in plasma was 1.1–1.3 μg/mL, so can not achieve levels used in most in-vitro studies.
Pathways:
- results for both inducing and reducing
ROS in cancer cells. In normal cell seems to consistently lower ROS. Reports show both ROS↑ and ROS↓ in cancer models; systemic pro-oxidant effects may require higher exposures than typical oral dosing, but local or combination contexts may differ. (level in GUT could be much higher (800uM).
- ROS↑ related:
MMP↓(ΔΨm),
Ca+2↑,
Cyt‑c↑,
Caspases↑,
DNA damage↑,
cl-PARP↑,
- Raises
AntiOxidant
defense in Normal Cells:
ROS↓,
NRF2↑,
SOD↑,
GSH↑,
Catalase↑,
- lowers
Inflammation :
NF-kB↓">NF-kB↓,
COX2↓,
p38↓(context-dependent; often stress-activated), Pro-Inflammatory Cytokines :
NLRP3↓,
IL-1β↓,
TNF-α↓,
IL-6↓,
IL-8↓
- inhibit Growth/Metastases :
TumMeta↓,
TumCG↓,
EMT↓,
MMPs↓,
MMP2↓,
MMP9↓,
TIMP2,
uPA↓,
VEGF↓,
FAK↓,
NF-κB↓,
CXCR4↓,
TGF-β↓,
α-SMA↓,
ERK↓
- reactivate genes thereby inhibiting cancer cell growth :
HDAC↓,
DNMTs↓,
P53↑,
HSP↓,
- cause Cell cycle arrest :
TumCCA↑,
cyclin D1↓,
cyclin E↓,
CDK2↓,
CDK4↓,
- inhibits Migration/Invasion :
TumCMig↓,
TumCI↓,
TNF-α↓,
FAK↓,
ERK↓,
EMT↓,
- inhibits
glycolysis
and
ATP depletion :
HIF-1α↓,
PKM2↓,
cMyc↓,
GLUT1↓,
LDH↓,
LDHA↓,
HK2↓,
PFKs↓,
GRP78↑(ER stress),
Glucose↓,
GlucoseCon↓
- inhibits
angiogenesis↓ :
VEGF↓,
HIF-1α↓,
Notch↓,
PDGF↓,
EGFR↓,
- inhibits Cancer Stem Cells :
CSC↓,
Hh↓,
GLi1↓,
β-catenin↓,
Notch2↓,
OCT4↓,
- Others: PI3K↓,
AKT↓,
JAK↓,
STAT↓,
Wnt↓,
β-catenin↓,
AMPK,
ERK↓,
JNK,
- SREBP (related to cholesterol).
- Synergies:
chemo-sensitization,
chemoProtective,
RadioSensitizer,
RadioProtective,
Others(review target notes),
Neuroprotective,
Cognitive,
Renoprotection,
Hepatoprotective,
CardioProtective,
- Selectivity:
Cancer Cells vs Normal Cells
| Rank |
Pathway / Axis |
Cancer Cells |
Normal Cells |
TSF |
Primary Effect |
Notes / Interpretation |
| 1 |
ROS / redox buffering + mitochondrial protection |
Often ↑ stress susceptibility; can support apoptosis when survival signaling is blocked |
↓ oxidative stress; mitochondrial protection |
P, R, G |
Context-selective redox modulation |
Silymarin is classically cytoprotective/antioxidant in normal tissues (notably liver), while in tumors it can weaken pro-survival adaptation and increase vulnerability to stressors and therapy. |
| 2 |
Intrinsic apoptosis (mitochondria → caspases) |
↑ apoptosis signaling; ↑ caspase activation |
↔ minimal activation |
G |
Cell death execution |
Common downstream outcome in cancer models: apoptosis increases after earlier signaling/redox shifts and/or checkpoint disruption. |
| 3 |
Cell-cycle control (cyclins/CDKs; checkpoints) |
↑ arrest (G1/S or G2/M depending on model) |
↔ |
G |
Cytostasis |
Typically observed as reduced proliferation with checkpoint engagement; timing usually later than kinase phosphorylation changes. |
| 4 |
NF-κB inflammatory transcription |
↓ NF-κB activity; ↓ inflammatory/pro-survival tone |
↔ or protective anti-inflammatory effect |
R, G |
Anti-inflammatory / anti-survival transcription |
NF-κB suppression can reduce tumor-promoting inflammation and blunt stress-adaptive survival programs. |
| 5 |
JAK/STAT3 axis (incl. PD-L1 / immune escape programs in some models) |
↓ STAT3 signaling (context); may ↓ PD-L1 in certain tumor contexts |
↔ |
R, G |
Reduced survival + immune-evasion signaling |
Reported to attenuate STAT3-driven tumor programs and, in some contexts, reduce immune-suppressive signaling (model dependent). |
| 6 |
PI3K → AKT → mTOR survival / growth signaling |
↓ PI3K/AKT/mTOR signaling (context) |
↔ |
R, G |
Growth/survival suppression |
Reduced PI3K/AKT/mTOR tone increases sensitivity to apoptosis and can reinforce cell-cycle arrest. |
| 7 |
MAPK re-wiring (ERK/p38/JNK balance) |
Stress-MAPK shifts; ERK tone often reduced or re-patterned |
↔ |
P, R, G |
Signal reprogramming |
Early phosphorylation shifts can precede later gene-expression changes; exact ERK direction is model and dose dependent. |
| 8 |
Angiogenesis (VEGF and angiogenic factors) |
↓ VEGF / angiogenesis outputs |
↔ |
G |
Anti-angiogenic support |
Typically reflected in reduced pro-angiogenic expression/secretion and angiogenesis-related phenotypes over longer windows. |
| 9 |
EMT / invasion / migration programs (incl. TGF-β/Smad-associated EMT in some systems) |
↓ EMT markers; ↓ migration/invasion |
↔ |
G |
Anti-invasive phenotype |
Often presents as restoration of epithelial markers and suppression of migration/invasion assays; commonly a later phenotype-level outcome. |
| 10 |
Xenobiotic handling (Phase I/II enzymes; cytoprotection / chemoprevention framing) |
May alter carcinogen activation/detox balance |
↑ detox / cytoprotection against xenobiotics |
G |
Chemopreventive protection |
A key “dual strategy” theme: protection of normal tissue from toxins/therapy while modulating tumor response pathways. |
| 11 |
Drug resistance / efflux (MDR phenotype; P-gp-related resistance in some models) |
May ↓ functional MDR and ↑ chemo sensitivity (context) |
↔ |
R, G |
Chemo-sensitization support |
Reported synergy with chemotherapy in resistant tumor settings; transporter direction can be context-specific, so present as “reported to reduce functional resistance” rather than a universal single-transporter claim. |
| 12 |
Immune microenvironment signaling (cytokines / macrophage recruitment in some models) |
May ↓ pro-tumor cytokine programs and recruitment signals (context) |
↔ |
G |
Anti-inflammatory tumor microenvironment shift |
Immune-modulatory effects are increasingly discussed, but they are more model-dependent and typically show on longer time scales. |
Time-Scale Flag (TSF): P / R / G
- P: 0–30 min (primary/physical–chemical effects; rapid signaling / phosphorylation shifts)
- R: 30 min–3 hr (redox signaling + acute stress-response signaling)
- G: >3 hr (gene-regulatory adaptation and phenotype-level outcomes)
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