From an article: Inhibition of Kupffer cell functions as an explanation for the hepatoprotective properties of silibinin. by Dehmlow C; Erhard J; de Groot H;Source: Hepatology Date of Pub: 1996 Apr Issue: 4 Volume: 23 Pagination: 749-54 Address: Institut fÍur Physiologische Chemie, UniversitÍatsklinikum, Essen, Germany.

Silibinin, the main ingredient extracted from the milk thistle Silybum marianum, displays liver-protecting properties in acute and chronic liver injury. To further explain how it acts, this investigator studied the effects of silibinin on different functions of certain rat cells, namely the formation of superoxide anion radical (02-), nitric oxide, tumor necrosis factor alpha (TNF-alpha), prostaglandin and leukotriene. Production of 02- and NO nitric oxide were inhibited (stopped) depending on the dose, with a 50 percent inhibitory concentration value around 80 micro mol/L. No effect on TNF-alpha formation was found. Opposite effects were found on the cyclooxygenase and 5-lipoxygenase pathway of arachidonic acid metabolism. Although no influence on prostaglandin formation was observed with silibinin concentrations up to 100 micro mol/L, a strong inhibitory effect on leukotriene formation was found. The amount of silibinin needed to inhibit the formation of this eicosanoid was determined to be 15 micro mol/L. The strong inhibition of leukotriene, formation by silibinin was confirmed in experiments with phagocytic cells isolated from human liver. Therefore, while rather high amounts of silibinin are necessary to diminish free radical formation by activated Kupffer cells, significant inhibition of the 5-lipoxygenase pathway already occurs at silibinin concentrations which are achieved in vivo. Selective inhibition of leukotriene formation by Kupffer cells can at least partly account for the liver-protective properties of silibinin.

PHYTOGENIC AGENTS IN THE THERAPY OF LIVER DISEASE

Author: THABREW MI, UNIV LONDON KINGS COLL, SCH MED & DENT, INST LIVER STUDIES, BESSEMER RD, LONDON SE5 9PJ, ENGLAND Source: PHYTOTHERAPY RESEARCH 1996 SEP;10(6):461-467

Abstract: Plant extracts have been used by traditional medical practitioners for the treatment of liver disorders for centuries. This article reviews the clinical trials carried out with thirteen plants and their constituents in patients with liver disease, including acute viral hepatitis, chronic viral hepatitis, chronic cholecystitis, alcoholic liver disease and mushroom poisoning, There is considerable scientific evidence that phytogenic agents can have significant beneficial effects on liver dysfunction and the course of liver disease. At present, silymarin has the most proven overall clinical hepatoprotective effects, although glycyrrhizin appears to be more beneficial in chronic viral hepatitis, With the high worldwide incidence of viral hepatitis, further study of isolated phytochemicals is important in relation to their potential antiviral activity against the different hepatitis viruses.