Vaccine and Infectious Disease Division

The multitalented milk thistle

Current therapies for chronic hepatitis C liver disease are expensive, have significant side effects, and are frequently ineffective.  As a result, many patients turn to herbal remedies, such as milk thistle extract, to supplement or replace pharmaceutical regimens.  Previous research by VIDD affiliate investigator Dr. Stephen Polyak and colleagues found that silymarin, an extract of milk thistle, inhibits hepatitis C virus infection in cell culture and suppresses T cell proliferation and cytokine production, which may calm inflammation in chronic liver disease and reduce tissue damage.

To further investigate the antiviral properties of silymarin, Polyak and colleagues studied the effects of the extract on various aspects of a cell culture model of hepatitis C virus infection.  Through a series of experiments, the researchers found that silymarin inhibits entry of the virus into liver cells, reduces expression of viral RNA and protein, and inhibits virus production from infected cells.  Interestingly, silymarin also inhibited entry of other types of enveloped viruses into the liver cells, suggesting that it might be useful as a therapeutic agent against multiple types of viral infection.  Although the precise mechanisms of silymarin’s anti-viral action remain unidentified, this study will help guide future research into important therapeutic pathways.

Wagoner J, Negash A, Kane OJ, Martinez LE, Nahmias Y, Bourne N, Owen DM, Grove J, Brimacombe C, McKeating JA, Pécheur EI, Graf TN, Oberlies NH, Lohmann V, Cao F, Tavis JE, Polyak SJ. Multiple effects of silymarin on the hepatitis C virus lifecycle. Hepatology. 2010 Jun;51(6):1912-21.

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