Milk thistle (MT) (Silybum marianum) is an herb with a 2000 year history of use. Silymarin (SIL) is an extract of milk thistle. It consists of flavonoids and lignans. The main flavonoid is silibinin. SIL has no toxicity to the fetus before birth or to the child during breastfeeding.
SIL is used, primarily, in liver disease and bile problems. It improves liver function in alcoholic liver cirrhosis. It improves bile flow in cholestasis, increases bile salt production, and increases bicarbonate production. (Cholestasis is a block in bile flow due to liver disease or a bile duct blockage.) It protects the liver from inflammation and can be used for hepatitis, viral hepatitis and fatty liver.
SIL is an antioxidant and a 5-lipoxygenase inhibitor, which blocks some forms of cancer, such as melanoma. It is effective in reducing the effects of Amanita mushroom poisoning.
SIL blocks vascular endothelial growth factor (VEGF,) an enzyme which promotes the growth of new blood vessels. Blocking this process of angiogenesis is believed to be a good target in treating wet macular degeneration and cancers. The VEGF blocking action of milk thistle may be of benefit in condyloma acuminatum, sometimes called venereal warts.
Skin cancers from chemical or UV light exposure are the most frequent skin cancer. The risk of these cancers is reduced by silymarin. The use of silymarin in a skin cream has been suggested.
The binding of SIL with water-soluble flavonoids makes SIL phytosome, the most absorbable form. The best seems to be SIL with phosphatidylcholine. SIL phytosome improves recovery from alcoholic hepatitis, acute viral hepatitis A and B, and hepatitis of unknown cause. Phosphatidylcholine binding increases the absorption of SIL by 2 to 6 times. Silymarin-phosphatidylcholine 800-1600 mg/day given for up to 120 days reduces liver damage from cirrhosis and hepatitis.
Glutathione enzyme is needed to detoxify the body. The body becomes depleted of glutathione when there is excessive toxicity. Milk thistle increases the liver’s production of glutathione.
SIL use in hepatitis B and hepatitis C improves blood tests of liver function. But, SIL does not improve the viral load or microscopic appearance of the liver structure.
Silibinin reduces cancer in animal models of colorectal, prostate, skin, bladder, and lung cancers. Silibinin reduces colon cancer in people with familial adenoma polyposis, in which people have high rates of colon cancer in colon polyps.
SIL is a good blocker of carbonic anhydrase enzymes. This is considered to be treatment of acid-base imbalance, cancer, edema, glaucoma, obesity, epilepsy, and osteoporosis.
Hepatocellular cancer rates are quite high, perhaps, due to high rates of hepatitis B and of hepatitis C. Silibinin shows anticancer effects against hepatocellular cancer cells by increasing apoptosis in lab tests. Clinical studies are needed.
CONCLUSION: Milk thistle, silymarin and silibinin have numerous properties making them protective against many liver problems. They reduce toxicities of many types and are useful in treating various diseases and cancers by the inhibition of various enzymes. Silymarin phosphatidylcholine is the most effective form.
The following are the references for Milk thistle and silymarin (silibinin.)
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Kidd, PM. Bioavailability and Activity of Phytosome Complexes from Botanical Polyphenols: the Silymarin, Curcumin, Green Tea, and Grape Seed Exracts. Altern Med Rev. 2009 Sep;14(3):226-46. University of California, Berkeley, California, USA. (Summary #425.)
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Senturk, M., et al. In Vitro Inhibition of Human Carbonic Anhydrase I and II Isozymes with Natural Phenolic Compounds. Chem Biol Drug Des. 2011 Feb 19 (Epub ahead of print.) Agri Ibrahim Cecen University, Agri, Turkey, etc. (Summary #482.) PMID: 21332948.
Varghese, L. et al. Cancer Therapy: Silibinin Efficacy Against Human Hepatocellular Carcinoma. Clin. Cancer Res. 2005 Dec. 1;11(23):8441-8. University of Colorado Health Sciences Center, Denver, Colorado, USA. (Summary #245.)
Zakaria, ZA., et al. Hepatoprotective Activity of Dried- and Fermented-processed Virgin Coconut Oil. Evid. Based Complement Alternat med. 2011;2011:142739. Universiti Putra Malaysia, Serdang, Selangor, Malaysia. (Summary #471.)
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