Therapeutic administration of an ingredient of aged-garlic extracts, S-allyl cysteine resolves liver fibrosis established by carbon tetrachloride in rats

S-allyl cysteine (SAC) is the most abundant compound in aged garlic extracts (AGEs). AGE has been reported to ameliorate the oxidative damage implicated in a variety of diseases. However, the effects of SAC have not been established in liver cirrhosis. The aim of this study was to examine the effect of therapeutic administration of SAC in liver cirrhosis by chronic carbon tetrachloride (CCl4) administration in rats. SAC or other cysteine compounds were administered from 4 weeks when liver fibrosis was confirmed to be in process. CCl4 administration elevated plasma alanine aminotransferase, plasma lipid peroxidation, liver hydroxyproline, and liver transforming growth factor (TGF)-β at 12 weeks. SAC prevented these changes induced by CCl4. Furthermore, SAC improved survival in a dose-dependent manner following consecutive CCl4 administration. The inhibitory mechanisms may be associated with a decrease in the profibrogenic cytokine, TGF-β as well as the antioxidative properties of SAC.