[Rich66]

1: Cancer Lett. 2008 Oct 8;269(2):352-62. Epub 2008 May 9. Links

Multitargeted therapy of cancer by silymarin.

Ramasamy K, Agarwal R.
Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver, 4200 East Ninth Street, Box C238, Denver, CO 80262, USA.
Silymarin, a flavonolignan from milk thistle (Silybum marianum) plant, is used for the protection against various liver conditions in both clinical settings and experimental models. In this review, we summarize the recent investigations and mechanistic studies regarding possible molecular targets of silymarin for cancer prevention. Number of studies has established the cancer chemopreventive role of silymarin in both in vivo and in vitro models. Silymarin modulates imbalance between cell survival and apoptosis through interference with the expressions of cell cycle regulators and proteins involved in apoptosis. In addition, silymarin also showed anti-inflammatory as well as anti-metastatic activity. Further, the protective effects of silymarin and its major active constituent, silibinin, studied in various tissues, suggest a clinical application in cancer patients as an adjunct to established therapies, to prevent or reduce chemotherapy as well as radiotherapy-induced toxicity. This review focuses on the chemistry and analogues of silymarin, multiple possible molecular mechanisms, in vitro as well as in vivo anti-cancer activities, and studies on human clinical trials.

Milk Thistle (from MD Anderson site)

Background and Health Claims
The milk thistle plant, also known as marian thistle, is native to Europe. The ripe fruits, often called seeds, are the medicinal portion of the plant.
Milk thistle is being studied for its liver protecting effects and anticancer activity. Flavolignans (especially silymarin) are the compounds in milk thistle that provide protection against a variety of toxins that may damage the liver, including poisonous mushrooms, ethanol (found in alcoholic beverages) and carbon tetrachloride (a solvent used in pharmaceutacal preparation).
Silymarin and other flavolignans seem to protect undamaged liver cells by acting on the cell membranes to prevent the entry of toxins. Milk thistle also stimulates protein synthesis, which accelerates cell regeneration within the liver. It is believed to have antioxidant properties.
In two studies using mice, topical application of milk thistle after exposure to ultraviolet B sun rays reduced the effects of a carcinogen known to promote skin cancer. A third study found that another component of milk thistle (flavonoid silibinin), given before chemotherapy with the drug cisplatin, significantly decreased toxic effects in the kidneys of rats without inhibiting the therapy’s antitumor activity.
Precautions
At this time, no adverse effects have been associated with milk thistle use. However, occasional mild laxative effects and allergic reactions have been observed. Milk thistle is not recommended for patients with liver damage known as decompensated cirrhosis.
Milk thistle may be useful for patients receiving chemotherapy agents that are especially toxic to the kidney or liver; however, controlled human studies are needed to determine the effects of milk thistle’s long-term use.
Milk thistle tea is considered an ineffective form.
Dose
The reported adult dose of milk thistle is 12-15 g of seeds daily, or an equivalent formulation of 200-400 mg silymarin, calculated as silybin.