Milk Thistle May Protect Against Liver Cancer

New research from the University of California, Irvine, has found that a component of milk thistle, called silybinin, may prevent liver cancer.¹ Milk thistle (Silybum marianum) is an herb native to Eurasia that is used in a variety of liver problems in traditional medicine. Milk thistle is also commonly eaten as food in Europe, where young leaves are used in salads, young stalks steamed like asparagus, and the thistle heads boiled or roasted like artichokes.

First a little background on milk thistle and it's active components. What is typically called the "active component" in milk thistle, silymarin, is really a mixture of four antioxidant compounds (silybinin, isosilybinin, silychristin, and silidianin) called flavonolignans. Silybinin makes up the majority, about 70%, of the silymarin complex. It is silybinin, that was studied in this in vitro test.

The researchers tested various doses of silybinin, ranging between 10 and 240 micromoles per liter, against four different human liver cancer cell lines, HuH7, HepG2, Hep3B, and PLC/PRF/5. The researchers found a dose-dependent result above 180 micromoles per liter with an IC50 of 240 micromoles per liter. IC50 is the concentration level at which 50% of the cell population growth is inhibited. At 240 micromoles per liter, apoptosis (programmed cell death) increased nine-fold. Silybinin was also found to alter the expression of genes that promote the growth of blood vessels needed by the rapidly growing cancer cells. The researchers concluded "our findings not only indicate silibinin's novel anti-cancer mechanisms, but also provide additional targets for searching new agents for [hepatocellular carcinoma] chemoprevention." Of course, much more work will need to be done before the use of milk thistle or silybinin can be suggested as an adjunct therapy. However, this finding is not the first such finding for a milk thistle compound. A study published in the June 21, 2006 issue of the Journal of the National Cancer Institute found similar results for silybinin on lung cancer in mice.²

Learn more about the many potential benefits of milk thistle and our other liver-supporting products here.

1. Lah, J. J., W. Cui, et al. (2007). "Effects and mechanisms of silibinin on human hepatoma cell lines." World J Gastroenterol 13(40): 5299-305.

2. Singh, R. P., G. Deep, et al. (2006). "Effect of silibinin on the growth and progression of primary lung tumors in mice." J Natl Cancer Inst 98(12): 846-55.