Metabolites of diallyl disulfide and diallyl sulfide in primary rat hepatocytes

The objectives of this study were to analyse and identify the metabolites of diallyl disulfide (DADS) and diallyl sulfide (DAS) in primary rat hepatocytes prepared by collagenase perfusion. According to the results, allyl mercaptan (AM) and allyl methyl sulfide (AMS) were the metabolites of DADS. The highest amount of AMS (0.93 +/- 0.08 mu g/ml at 90 min) was much less than that of AM (46.2 +/- 6.6 mu g/ml at 60 min). Combined with the Purge and Trap using a gas chromatography-mass spectrometry (GC-MS) system, it is very useful to detect the trace amounts of metabolites in primary rat hepatocytes. Results also showed that AMS was a metabolite of DAS. The highest amount of AMS in the extracellular fluid of hepatocytes was 0.63 +/- 0.16 mu g/ml at 30 min of incubation. (C) 2000 Elsevier Science Ltd. All rights reserved

Effect of diallyl sulfide and diallyl disulfide, the active principles of garlic, on the aflatoxin B-1-induced DNA damage in primary rat hepatocytes

The objective of this study was to investigate the effect of the active principles in garlic-diallyl sulfide (DAS) and diallyl disulfide (DADS)-on aflatoxin B-1 (AFB(1))-induced DNA damage in primary rat hepatocytes. Primary rat hepatocytes, induced with DNA damage using 10 muM AFB(1) were used as an experimental model. According to the results of LDH leakage, 0.5 and 2 mM of DAS or 0.5 and 1 mM of DADS significantly increased the viability of hepatocytes compared with the AFB(1) controls after 4, 8 and 24 h treatment (P <0.05). According to the results of unscheduled DNA synthesis (UDS) test. 0.5 and 2 mM of DAS or 0.5 acid 1 mM of DADS could significantly decrease the DNA damage induced by AFB(1) (P<0.05). Furthermore, 0.5 and 2 mM DAS or 0.5 and 1 mM DADS could increase the glutathione S-transferase (GST) and glutathione peroxidase (GPx) activities as compared with the AFB(1) controls after 24 h treatment (P<0.05). Results of immunoblot analysis of cytosolic GST isoenzyme indicate that the levels of GST isoform Ya, Yb2 and Yc were markly increased after treatment with 0.5 and 2 mM DAS or 0.5 and 1 mM DADS compared with the AFB(1) control. These results indicate that 0.5 and 2 mM DAS or 0.5 and 1 mM DADS might protect hepatocytes from AFB(1)-induced DNA damage via increasing the activities of GST and GPx. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved

Diallyl trisulfide modulates cell viability and the antioxidation and detoxification systems of rat primary hepatocytes

This study investigated the effects of various concentrations of diallyl trisulfide (DATS) and incubation times on cell viability, glutathione (GSH) content, and GSH-related enzyme activity in rat primary hepatocytes. Isolated and cultured primary rat hepatocytes were used as an experimental model. Cells were treated with 0 (control), 0.025, 0.05, or 0.25 mmol/L DATS for 0, 4, 8, or 24 h. After 24 h of treatment, some cells were incubated in fresh medium without DATS for an additional 24 h (48-h incubations). Based on lactate dehydrogenase (LDH) leakage and morphological examination, hepatocytes treated with 0.025 mmol/L DATS did not differ from the control cells at 4, 8, 24, and 48 h of incubation. However, LDH leakage was higher than in the control cells (P < 0.05) when the hepatocytes were treated with 0.05 or 0.25 mmol/L DATS for 4 h or more. The intracellular GSH levels of hepatocytes treated with 0.025 or 0.05 mmol/L DATS were higher than those of the control cells (P < 0.05), whereas those treated with 0.25 mmol/L DATS did not differ. The activity of glutathione reductase (GRd) was higher than in the control cells at 24 h (P < 0.05) when the hepatocytes were treated with 0.025 mmol/L DATS. When the hepatocytes were treated with 0.025 mmol/L DATS, the activity of glutathione S-transferase (GST) was higher than in the control cells at 48 h (P < 0.05). In hepatocytes treated with 0.05 mmol/L DATS, the activity of GST and glutathione peroxidase (GPx) was higher than in the control cells (P < 0.05) at 24 and 48 h of incubation. The results indicate that 0.025 or 0.05 mmol/L DATS could enhance antioxidation and detoxification capabilities by increasing the intracellular GSH level and the activity of GPx, GRd, or GST in rat primary hepatocytes. However, 0.05 or 0.25 mmol/L DATS might adversely affect the viability of hepatocytes

Effects of organosulfur compounds from garlic oil on the antioxidation system in rat liver and red blood cells

The modulation of garlic oil (GO) and three allyl compounds, diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS), on the antioxidation system in rat livers and red blood cells was examined. Rats were orally administered GO (200 mg/kg body weight), DAS (20, 80 mg/kg body weight), DADS (80 mg/kg body weight) or DATS (70 mg/kg body weight) three times a week for 6 weeks. Control rats received corn oil (2 ml/kg body weight) alone. GO, DADS and DATS treatment significantly increased the glutathione (GSH) content (48-84%) in red blood cells (P < 0.05). DATS displayed a greater enhancement than GO and DADS (P < 0.05). Hemolysis induced by tert-butyl hydroperoxide was not suppressed by GO or allyl compound treatment although higher GSH content was evident. Hepatic GSH was not influenced by garlic components. In rat livers, DADS and DATS significantly increased the activity of GSH reductase (46 and 54%, respectively) and of GSH S-transferase (GST) (63 and 103%, respectively), but decreased the GSH peroxidase activity (27 and 28%, respectively). In contrast, GSH reductase and GST activities in the DAS group, either 20 or 80 mg/kg body weight, were similar to the control group. A decrease of GSH peroxidase activity was observed in rats dosed with 80 mg/kg body weight (P < 0.05). An increase in GST activity and a decrease in GSH peroxidase activities were also noted in GO-treated rats (P < 0.05). In red blood cells, three GSH-related antioxidant enzyme activities were not affected by garlic oil and its organosulfur components. Immunoblot assay showed that, accompanying the increase in hepatic GST activity, GO, DADS, DAS (80 mg/kg body weight) and DATS increased the expression of GST Ya, Yb1 and Yc proteins. Results indicate that GO and three allyl compounds play a differential role in modulation of the GSH-related antioxidant system in rat livers and red blood cells. (C) 2001 Elsevier Science Ltd. All rights reserved

Dietary fat and garlic oil independently regulate hepatic cytochrome P(450)2B1 and the placental form of glutathione S-Transferase expression in rats

The individual and combined effects of dietary fat and garlic oil on two drug-metabolizing enzymes, cytochrome P-450 2B1 and the placental form of glutathione (GSH) S-transferase (PGST), in rat liver were examined in this study. Rats were fed a low corn oil, high corn oil or high fish oil diet and received various amount of garlic oil (0, 30, 80, 200 mg/kg body) orally three times per week for 6 wk. The fat energy in the low and high fat diets accounted for 11.6 and 45.7% of total energy, respectively. Final body weights did not differ among the three dietary fat groups and were not affected by garlic oil treatment. The fatty acid profile in hepatic phospholipids revealed higher eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22.6(n-3)] levels in the fish oil-fed group than in the low and high corn oil-fed groups (P < 0.05). In contrast, the corn oil-fed groups had greater hepatic phospholipid arachidonic acid [20:4(n-6)] levels (P < 0.05). Both dietary fat and garlic oil significantly affected hepatic cytochrome 7-pentoxyresorufin O-dealkylase (PROD) activity and GST activity toward ethacrynic acid. Rats fed the high fish oil diet had 85 and 51% higher PROD activity compared with those fed the low or the high corn oil diet, respectively (P < 0.05). The GST activity in the high fish oil and the high corn oil groups was 33 and 18% higher than that in the low corn oil group (P < 0.05), respectively, and the GST activity in rats fed the high fish oil diet was higher than in those fed the high corn oil diet (P < 0.05). Garlic oil dose-dependently increased GST activity. No interaction between dietary fat and garlic oil on PROD or GST activity was noted. Northern and Western blot analysis revealed that dietary fish oil increased both cytochrome P-450 2B1 and PGST mRNA and protein levels. Cytochrome P-450 2B1 and PGST mRNA and protein levels were also dose-dependently increased by garlic oil treatment. The effects of garlic oil and dietary fat on P-450 2B1 and PGST mRNA and protein expression were independent. These results indicate that dietary fat and garlic oil independently modulate P-450 2B1 and PGST expression at transcriptional and/or post-transcriptional stages