Effect of the active principle of garlic-diallyl sulfide-on cell viability, detoxification capability and the antioxidation system of primary rat hepatocytes

The objectives of this study were to investigate the effects of various concentrations and incubation time intervals of diallyl sulfide (DAS), an active principle of garlic, on cell viability, and glutathione (GSH) concentration and its related enzymes activities in rat hepatocytes. According to the results of lactate dehydrogenase (LDH) leakage and microscopic examination, 0.5 or 1 mM DAS treatment did not have any adverse effects on the viability of hepatocytes. Intracellular GSH contents of cells treated with 0.5 and 1 mM DAS (58.6 and 66.4 nmol GSH/mg protein, respectively) were higher than in the controls (54.2 nmol GSH/mg protein), around 8-23%, at 24 hr of incubation; a significant difference (P < 0.05) was observed for 1 mM DAS treatment at 48 hr. This phenomenon is beneficial to the detoxification and antioxidation capabilities of hepatocytes. Further, when the hepatocytes were treated with 0.5 or 1 mM DAS, the activities of glutathione S-transferase (GST), glutathione peroxidase (GPx) and glutathione reductase (GRd) were almost the same as those of the controls. On the other hand, treatment with 5 mM DAS was associated with a significant decrease (P < 0.05) in cell viability, namely in increased LDH leakage (50% at 24-hr treatment), significant changes in the morphology of the hepatocytes, low intracellular GSH level (45% lower than in the controls at 24-hr treatment), and low activities of GST, GPx and Grd.