ABSTRACT
The Chinese herbal medicine Sho-saiko-to, a mixture of seven herbal preparations, is an officially approved prescription drug in Japan and is widely administered in Japan to patients with chronic hepatitis C virus (HCV) infection. The most common cause of hepatic fibrosis is chronic HCV infection, the characteristic feature of which is hepatic steatosis. Hepatic steatosis leads to an increase in lipid peroxidation in hepatocytes, which in turn leads to the activation of hepatic stellate cells (HSCs). HSCs are also thought to be the primary target cells of inflammatory stimuli, and produce collagen. Tests indicate that Sho-saiko-to improves liver function, and a prospective study reported a reduced incidence of hepatocellular carcinoma in patients with HCV-related cirrhosis. However, little information is available concerning the mechanism by which Sho-saikoto protects against hepatic fibrosis and carcinoma. Several laboratories, including ours, have demonstrated the preventive and therapeutic effects of Sho-saiko-to on experimental hepatic fibrosis, as well as its inhibitory effect on the activation of HSCs. We provided evidence that Sho-saiko-to functions as a potent fibrosuppressant via the inhibition of oxidative stress in hepatocytes and HSCs, and that its active components are baicalin and baicalein. In addition, Sho-saiko-to has anticarcinogenic properties in that it inhibits chemical hepatocarcinogenesis in animals, inhibits the proliferation of hepatoma cells by inducing apoptosis, and arrests the cell cycle. Among the active components of Shosaiko-to, baicalin, baicalein, and saikosaponin-a have the ability to inhibit cell proliferation. It should be noted that baicalin and baicalein are flavonoids, the chemical structures of which are very similar to those of silybinin and quercetin, which show antifibrogenic activities. This may provide valuable information on the search for novel antifibrogenic agents.
