A laboratory study suggests that silymarin—an extract from the milk thistle plant—has multiple effects against the lifecycle of the hepatitis C virus. Hepatitis C is a chronic (long lasting) disease that primarily affects the liver and is often difficult to cure. The laboratory study examined the antiviral properties and mechanisms of silymarin on cultured (grown in a lab) human liver cells infected with the virus. The study, funded in part by NCCAM, was published in the journal Hepatology.
The researchers grew human liver cells and infected them in vitro with the hepatitis C virus. The cells were then exposed to either standard hepatitis C drug treatment or to a diluted dose of silymarin. By analyzing the interactions between silymarin and the virus, the researchers observed that silymarin prevented the entry and fusion of the hepatitis C virus into the target liver cells. They also found that silymarin inhibited the ability of the virus to produce RNA (a chemical that plays an important role in protein synthesis and other chemical activities of the cell), interfering with a portion of the virus's lifecycle. When measured against untreated cells, silymarin also significantly decreased viral load (the amount of virus in the cells), although to a lesser degree than treatment with interferon did. The researchers also found that silymarin prevented the cell-to-cell spread of the virus.
These findings build on previous research of silymarin's antiviral and anti-inflammatory properties and provide more information about the potential mechanisms involved in silymarin's antiviral actions. Further research, particularly in clinical trials, is needed to determine if silymarin could be a safe and effective supplement for treating hepatitis C in humans.
Wagoner J, Negash A, Kane OJ, et al. Multiple effects of silymarin on the hepatitis C virus lifecycle. Hepatology.;51(6):1912–1921.2010