Chronic hepatitis C is a slowly progressive liver disease that may evolve into cirrhosis with its potential complications of liver failure or hepatocellular carcinoma. Current therapy with α-interferon is directed at viral clearance, but sustained response is only achieved in 20–40% of patients without cirrhosis, and less than 20% in patients with cirrhosis who have the greatest need for therapy. Treatment for those who do not respond to anti-viral therapy is highly desirable.
In Japan glycyrrhizin has been used for more than 20 years as treatment for chronic hepatitis. In randomized controlled trials, glycyrrhizin induced a significant reduction of serum aminotransferases and an improvement in liver histology compared to placebo. Recently, these short-term effects have been amplified by a well-conducted retrospective study suggesting that long-term usage of glycyrrhizin prevents development of hepatocellular carcinoma in chronic hepatitis C.
The mechanism by which glycyrrhizin improves liver biochemistry and histology are undefined. Metabolism, pharmacokinetics, side-effects, and anti-viral and hepatoprotective effects of glycyrrhizin are discussed.