Alternatives in hepatoprotection: cytoprotection--influences on mono-oxidase system--free radical scavengers (a review).

Abstract

Three correlating fields of hepatoprotection have been reviewed: (1) "classic" gastrointestinal cytoprotection: (2) effects via the mixed function mono-oxidase enzyme system: (3) the role of the free radical scavengers and lipid peroxidation inhibiting agents. Gastrointestinal cytoprotection was originally defined in experimentally induced gastric mucosal injuries where several members of the prostaglandin group proved to be effective. Their capacity to increase the stability of biomembranes can be manifested also in hepatocytes, as PGE2 and PGI2 prevent the CCl4-toxicity in experimental animals. Induction of the mono-oxidase system (e.g. with barbiturates or with antioestrogens) may be useful by increasing bilirubin excretion and the biotransformation activity as well as possible by enhancing protein synthesis in liver cells. Inhibition of the mono-oxidases, on the other hand, can prevent the transformation of toxic substances into even more toxic metabolites and the production of free radicals. Free radical scavengers and inhibitors of lipid peroxidation play a central role in hepatoprotection. A flavonoid substance, (+)-cyanidanol-3 possessing many of the mentioned effects may be a promising alternative in the therapy of liver disease.