Vaccine and Infectious Disease Division

Milk thistle and the ailing liver

Medications for liver disease from chronic hepatitis C are often not effective, so in many cases patients turn to silymarin, an extract from milk thistle seeds.  However, this herbal remedy’s efficacy and mechanism by which it combats disease remain unclear. Now, a group of scientists led by VIDI affiliate investigator Dr. Chihiro Morishima have experimental evidence that silymarin may suppress T cells, thereby calming the inflammation that plagues sufferers of chronic liver disease.

To examine the effects of silymarin on the immune system of hepatitis patients, the scientists extracted T cells and other blood cells from people with and without hepatitis C (HCV) and exposed these cells to silymarin.  They found that the milk thistle extract inhibited the immune cells from secreting signaling molecules such as the cytokines TNFα, IFNγ, and IL-2 when these cells were stimulated with HCV proteins.  Silymarin also prevented the T cells from multiplying.

HCV infection often leads to liver fibrosis, the accumulation of scar tissue in the liver as a result of chronic inflammation, so silymarin’s ability to inhibit immune responses in T cells suggests that it might help fight liver disease.  Past research led by VIDI affiliate investigator Dr. Stephen Polyak indicated that silymarin additionally has antiviral and anti-inflammatory activities against HCV.  Clinical trials will be needed to test the remedy’s effectiveness in hepatitis patients.

Silymarin Inhibits in Vitro T Cell Proliferation and Cytokine Production in Hepatitis C Virus Infection.  Morishima C, Shuhart MC, Wang CC, Paschal DM, Apodaca MC, Liu Y, Sloan DD, Graf TN, Oberlies NH, Lee DY, Jerome KR, Polyak SJ.  Gastroenterology. 2009 Sep 23.