Effects of Graptopetalum paraguayense extract on tert-butylhydroperoxide-induced oxidative stress

BACKGROUND: Graptopetalum paraguayense E. Walther is used in folk medicine to lower blood pressure, protect liver function and relieve pain and infection. The effect and mechanism of its 50% ethanolic extract (GE50) were investigated in tert-butylhydroperoxide (t-BHP)-induced Wistar rats. The serum was analysed for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities while the tissue cytosols were analysed for lipid peroxidation, antioxidant level and enzyme activities. RESULTS: The liver was the primary target organ while the heart appeared to be the least responsive organ for t-BHP treatment among the three tissues investigated. t-BHP treatment increased serum AST and ALT activities, which are indicators of liver toxicity, while GE50 pretreatment reduced t-BHP-induced liver damage. t-BHP treatment induced lipid peroxidation in the liver and brain but not in the heart. GE50 pretreatment prevented t-BHP-induced lipid peroxidation by maintaining superoxide dismutase (SOD) activity as well as glutathione (GSH) and vitamin C levels in the liver and vitamin E level in the brain. Although t-BHP treatment did not induce lipid peroxidation in the heart, it caused a decrease in antioxidant level. GE50 pretreatment prevented the t-BHP-induced decrease in vitamin C level in the heart. CONCLUSION: GE50 pretreatment in rats protects the liver and brain from possible damage by t-BHP-induced lipid peroxidation. (c) 2007 Society of Chemical Industry.