Vaccine and Infectious Disease Division

Dissecting the anti-hepatitis effects of milk thistle

Hepatitis C is a chronic, common infection, causing liver disease that often requires transplantation. While standard treatments with the drugs pegylated IFN-α and ribavirin exist for infection with hepatitis C virus (HCV), they are only effective and tolerated in 55 percent of HCV patients. Alternative treatments to hepatitis liver disease are thus needed, and many patients self-prescribe silymarin, an extract of the milk thistle plant that is available as a supplement. Silymarin has been found to be somewhat effective in slowing hepatitis disease and fighting the virus, but how it works is not clear.

To probe which components of silymarin may be best used as hepatitis treatments, VIDI affiliate investigator Dr. Stephen Polyak and colleagues looked at how the eight compounds present in the extract protect human cells against HCV infection, inflammation, and oxidative stress.

They found that three of the compounds, isosilybin A, taxifolin, and silibinin, performed well in four out of five of these assays, indicating these three may be the most protective against liver disease. All of the compounds were more protective alone than the complete milk thistle extract, so isolating compounds from silymarin may lead to better treatments for hepatitis C down the road.

Identification of hepatoprotective flavonolignans from silymarin. Polyak SJ, Morishima C, Lohmann V, Pal S, Lee DY, Liu Y, Graf TN, Oberlies NH. Proc Natl Acad Sci U S A. 2010 Mar 30;107(13):5995-9.

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