Effects on Lipid Peroxidation and Antioxidative Enzymes of Euonymus alatus in Cultured Rat Hepatocytes

Abstract: The Euonymus alatus (Thunb.) Sieb. has long been used as a crude drug. In this paper, we investigate the effects of E. alatus on cultured hepatocyte cell system and lipid peroxidation in hydrogen peroxide (H₂O₂) treatment conditions. The study covers the physiological activity (the antioxidative activity and the nitrite‐scavenging effect) of E. alatus. H₂O₂ that can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. Treatment of E. alatus attenuated in cell killing enhanced by increasing concentrations of H₂O₂. The increased malondialdehyde level induced by H₂O₂ treatment was reduced by pre‐treatment of E. alatus. Furthermore, addition of E. alatus in cell culture medium significantly reduced cell killing and content of intracellular antioxidants. Changes in nitrite‐scavenging effect of E. alatus at various concentrations (5–25 mg/ml) and various pH levels (pH 1.2, 4.2 and 6.0) were also observed. The present study was also done to investigate the effects of E. alatus on cultured hepatocyte cell system, H₂O₂‐induced cytotoxicity and antioxidative enzyme activities, including catalase, superoxide dismutase, glutathione peroxidase and glutathione S‐transferase in H₂O₂ treatment conditions. E. alatus treatment had significant protective or elevating activities on these antioxidative enzyme activities compared to a normal group. The results indicate that E. alatus provides a strong antioxidant protection of cells against H₂O₂‐induced oxidative stress.