Herbal medicines, which have been used in China for thousands of years, are now being manufactured in Japan, in standardized form in terms of quality and quantities of ingredients. The Chinese herbal medicine
Sho-saiko-to is a mixture of seven
herbal preparations, which is widely administered in Japan to patients with
chronic hepatitis and
cirrhosis. In a prospective study, this herbal medicine was found to play a chemopreventive role in the development of
hepatocellular carcinoma in cirrhotic patients. However, little is known about the mechanism by which
Sho-saiko-to protects against hepatic
fibrosis and
carcinoma. Several laboratories, including ours, have clearly demonstrated the preventive and
therapeutic effects of
Sho-saiko-to on experimental hepatic
fibrosis, as well as its inhibitory effect on the activation of hepatic stellate cells, which are the major types of
collagen-producing cells. We provided evidence that
Sho-saiko-to functions as a potent anti-fibrosuppressant via the inhibition of oxidative stress in hepatocytes and hepatic stellate cells and that its active components are
baicalin and
baicalein. In addition,
Sho-saiko-to has anti-carcinogenic properties in that it inhibits chemical hepatocarcinogenesis in animals, acts as a
biological response modifier and suppresses the proliferation of
hepatoma cells by inducing apoptosis and arrests the cell cycle. Among the active components of
Sho-saiko-to,
baicalin,
baicalein and
saikosaponin-a have the ability to inhibit cell proliferation. It should be noted that
baicalin and
baicalein are
flavonoids with chemical structures very similar to
silybinin, which shows anti-fibrogenic activities. This may provide valuable information on the search for novel anti-fibrogenic agents.