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Milk thistle

Milk thistle (Silybum marianum), which is also commonly known as Marian thistle, St. Mary's thistle, is a native to the Mediterranean region, but has been naturalized in California and the eastern United States. This tall herb with prickly variegated leaves and milky sap has been used as a folk remedy for liver and biliary complaints for many years and recent research has supported such medicinal use. The extract of the milk thistle plant, Silybum marianum, which belongs to the aster family (Asteraceae or Compositae), comprises silymarin as the active constituent. Silymarin consists of a mixture of three bioflavinoids (flavonolignans), silybin, silydianin, and silychristine, found in the fruit, seeds, and leaves of the milk thistle plant. Silybin is the main component of silymarin, amounting to 60-70% by weight, and is thought to have the most biological activity. The active principles of this plant are flavonolignans, including silibine, silicristine and silidianine and isosilibinin collectively known as sylimarin. This compound has the highest grade of hepato-protective, hepato-generating, and anti-inflammatory activity. The mechanisms which explain its hepato-protector characteristics are diverse and include anti-oxidation, lipid anti-peroxidation, detoxification increase through a competitive inhibition with toxic substances, as well as protection against the depletion of glutathione. Silymarin is made up of three parts: silibinin, silidianin, and silicristin. Silibinin is the most active and is largely responsible for the benefits attributed to silymarin. As with other bioflavonoids, silymarin is a powerful antioxidant. Milk thistle extract is useful to protect or reverse damage to liver cells from toxins (e.g., alcohol, drugs, pesticides, poisons), to promote the regeneration of liver cells, to prevent or treat liver disease (e.g., liver cirrhosis, chronic hepatitis, and diabetes due to cirrhosis), indigestion, and cancer. Silymarin has been shown to have utility in many liver disorders including hepatitis, alcoholic liver disease, and hepatitis. It has also been shown to be useful for the treatment of toxin-induced liver toxicity including poisoning from death cap mushroom (Amanita phalloides). Silymarin's effect in preventing liver destruction and enhancing liver function relates largely to its ability to inhibit the factors that are responsible for hepatic damage, i.e., free radicals and leukotrienes, coupled with an ability to stimulate liver protein synthesis.

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