Monday, February 4, 2008

Milk Thistle: Liver Regenerator

Silymarin is the active constituent of the milk thistle seed. It consists of flavonolignans called: silibinin, silicrystin, and silidianin. Silibinin (also known as Silybin) makes up about 70% of Silymarin. Silymarin undergoes enterohepatic recirculation and has higher concentrations in liver cells. It is a potent inhibitor of tumor necrosis factor (TNF). TNF induces cytotoxicity, inflammation and apoptosis (cell death). These are effectively blocked by Silymarin. TNF is involved in the body's normal inflammation response. However, in certain diseases TNF is working overtime, causing cell death and damages healthy cells. This disregulation often occurs in diseases such as, Rheumatoid Arthritis. The way Silymarin works is unclear, it appears to work by facilitating cellular communication (intracellular signaling).

Silybin is an antioxidant, a free radical scavenger, and an inhibitor of lipid peroxidation. When an oxygen atom loses an electron, that electron floats around the body damaging tissues, cells or anything it comes in contact with. When an appliance, like a computer is plugged in and not grounded, and a power surge occurs, your computer is toast. Similarly, these electrons referred to as free radicals, damage cells and cause cell death.

In vitro, Silybin shows affinity for binding to P-glycoprotein. This protein is thought to be involved in the drug resistance of cancer cells. So by binding to this protein, which in essence protects cancer cells from being affected by drugs, it improves the efficacy of these drugs.
With respect to liver disease, Silymarin seems to cause an alteration of the outer hepatocyte (liver cell) cell membrane, preventing toxin penetration. It increases a protein called ribosomal protein synthesis, which stimulates liver regeneration and the formation of new hepatocytes. Silymarin might have antifibrotic, anti-inflammatory, and immunomodulating effects that could also be beneficial in liver disease.

Silymarin might protect against kidney damage. In vitro, it has been shown to protect the kidney cells from nephrotoxic drugs such as, acetaminophen, cisplatin, and vincristin. Silybin and Silicristin also appear to have a regenerative effect on kidney cells, similar to that on hepatic cells. It also seems to decrease insulin resistance, which in turn reduces blood glucose and lipid levels in patients with diabetes. Some research suggests that oxidative stress can contribute to pancreatic beta-cell dysfunction (these cells are responsible for producing insulin), reduced insulin secretion and insulin resistance. Silymarin is thought to reduce this oxidative stress.

Since so many drugs are metabolized by the liver, it has been a concern that this metabolism might be affected by Silymarin. Although it does seem to be an inhibitor of some liver enzymes, this inhibition does not so far seem significant with respect to drug metabolism.
In review, Silymarin is effective for liver disease, diabetes, and dyspepsia (acid reflux/heartburn). Normal dose is ranges from 100mg to 200mg of Silymarin 2-3 times a day.

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