Milk
thistle (Silybum marianum) is one of many alternative and complementary
therapies that have been proposed for the treatment of hepatitis
C virus (HCV) infection and resulting liver fibrosis. While some such agents
have long been used in traditional (e.g., Chinese) medicine, most have not been
studied in Western clinical trials.
In
the May 2007 issue of Gastroenterology, researchers from the University
of Washington in Seattle reported on a laboratory study of the anti-inflammatory
and antiviral properties of a standardized milk thistle silymarin extract known
as MK-001.
Results
•
MK-001
inhibited expression of tumor necrosis factor-alpha in anti-CD3 stimulated human
peripheral blood mononuclear cells.
•
MK-001
also inhibited nuclear factor kappa B-dependent transcription in human hepatoma
Huh7 cells.
•
MK-001
inhibited infection of Huh7 and Huh7.5.1 cells by JFH-1 virus (a strain of HCV
commonly used in laboratory studies) in a dose-dependent manner.
•
MK-001
displayed both prophylactic and therapeutic effects against HCV infection.
•
When
combined with interferon alpha, MK-001 inhibited HCV replication more than interferon
alone.
•
Commercially
available preparations of silymarin also displayed antiviral activity, but the
effects were not as potent as those of MK-001.
•
The
antiviral effects of MK-001 were attributable in part to induction of Stat-1 phosphorylation.
•
Interferon-independent
mechanisms were suggested when the extract was biochemically fractionated by high-performance
liquid chromatography.
•
The
compounds silybin A, silybin B, isosilybin A, and isosilybin B produced the strongest
anti-NF-kappa B and anti-HCV action.
•
These
effects were independent of cytotoxicity induced by MK-001.
Conclusion
In
conclusion, the authors wrote, "The data indicate that silymarin exerts anti-inflammatory
and antiviral effects, and suggest that complementary and alternative medicine-based
approaches may assist in the management of patients with chronic hepatitis C."
06/15/07
Reference SJ
Polyak, C Morishima, MC Shuhart, and others. Inhibition of T-cell inflammatory
cytokines, hepatocyte NF-kappa B signaling, and HCV infection by standardized
silymarin. Gastroenterology 132(5): 1925-1936. May 2007.
Milk
thistle (Silybum marianum) is one of many alternative and complementary
therapies that have been proposed for the treatment of 
