Silybin A

March 17, 2025
I鈥檓 from a thistle and can help your liver.
What molecule am I?
Image of Silybin A 3D Image of Silybin A

Silybin A, aka silibinin A, is a natural product produced in the fruits of the two species of milk thistle: Silybum eburneum, which grows in Spain and northern Africa, and the more common S. marianum, which is native to many countries around the world. The molecule has a diastereomer, silybin B1, that is formed in equal amounts by the plants; the combination of the two is simply called 鈥渟ilybin鈥�. The isomers are contained in silymarin2, the fruit extract that also contains other flavonolignans.

In 1965, H. Wagner, L. H枚rhammer, and R. M眉nster at the University of Munich (West Germany) reported the structure of what they called 鈥溾� from the fruit of S. marianum, one of which was silybin A. They also isolated the flavonolignan鈥檚 pentaacetate3. Three years later, Andrew Pelter at the University of Manchester (UK) and R. H盲nsel at the Free University Berlin used NMR to and called it 鈥渢he first flavonolignan鈥�.

Silymarin has been used in traditional medicine for centuries; it is even alluded to in the Old Testament (Genesis 3:18). Ancient physicians used it to treat gallbladder disorders and liver dysfunction. In the 1970s, the World Health Organization classified silymarin as an official medicine for protecting the liver.

Since its discovery, researchers have investigated silybin for medicinal properties. In 2017, Michal Bijak at the University of 艁贸d藕 (Poland) wrote an extensive review of the of silybin. The author concluded that 鈥渟ilybin is a very interesting chemical compound, the use of which as a dietary supplement is increasing all around the world, and this explains the recent studies aimed at increasing its oral bioavailability.鈥�

It is noteworthy that Bijak referred to silybin as a supplement and not a pharmaceutical. The US Food and Drug Administration has not approved it for any medical use, but it has registered silymarin as a dietary supplement. Silybin and its more bioavailable derivatives are approved in Europe for treating liver poisoning, such as that caused by eating toxic mushrooms.

In 2022, Anton Gillessen at Herz-Jesu-Hospital (M眉nster, Germany), Xiaoyuan Xu at Peking University Health Science Center (Beijing), and 11 colleagues at multiple institutions summarized the for using silymarin to treat toxic liver disease (TLD). The authors found that 鈥渟ilymarin as an antioxidant and hepatoprotective agent is safe and has reasonable clinical efficacy in TLD.鈥�

1. CAS Reg. No. 142797-34-0.
2. CAS Reg. No. 65666-07-1.
3. CAS Reg. No. 36804-18-9.

Silybin A hazard information

Hazard class*GHS code and hazard statement
Acute toxicity, oral, category 4H302鈥擧armful if swallowedChemical Safety Warning
Skin corrosion/irritation, category 2H315鈥擟auses skin irritationChemical Safety Warning
Serious eye damage/eye irritation, category 2AH319鈥擟auses serious eye irritationChemical Safety Warning
Specific target organ toxicity, single exposure, respiratory tract irritation, category 3H335鈥擬ay cause respiratory irritationChemical Safety Warning

*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. .

Molecule of the Future

BAY 26666051 is a phosphodiesterase 3 (PDE3) inhibitor that is being developed to combat melanoma. It is active against cancer cells that express the genes PDE3A and Schlafen family member 12 (SLFN12).聽

Molecule of the Future:  BAY 2666605

Researchers at the Broad Institute of MIT and Harvard (Cambridge, MA), Bayer AG (Berlin and Wuppertal, Germany), and Dana-Farber Cancer Institute (Boston) began their development of PDE3 inhibitors by examining the molecule (S)-DNMDP2, which preferentially kills two well-characterized lung cancer cell lines. This work led to an improved compound, BRD95003 with potency against several tumor models in vivo. From there, the researchers, led by Timothy A. Lewis at the Broad Institute, discovered BAY 2666605, which is optimized for clinical testing. The authors describe it as a .

1. CAS Reg. No. 2275774-60-0.
2. CAS Reg. No. 1630761-14-6.
3. CAS Reg. No. 1630760-75-6.

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Silybin A fast facts

CAS Reg. No.22888-70-6
SciFindern nameSee
Empirical
formula
C25H22O10
Molar mass482.44 g/mol
AppearanceWhite to pale yellow crystals
Melting point158 潞C
Water
solubility
鈮�50 mg/L
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