• The Korean Journal of Physiology and Pharmacology
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• v.1 no.2
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• pp.221-224
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• 1997

Effects of melatonin on hepatic glutathione-peroxidase (GSH-Px) and glutathione-reductase (GSH-reductase) activities were studied in Sprague-Dawley (SD) rats administered i.p. (10 mg/kg body weight) with melatonin during 15 days. The activity of cytosolic GSH-reductase in the liver was not changed by melatonin. However, melatonin injection increased significantly the activity of liver cytosolic GSH-Px activity compared with those in saline-treated rats. At the same time, plasma GSH-Px was also increased significantly in melatonin-treated rats. Since GSH-Px, a major antioxidative enzyme, removes $H_2O_2$ and lipid peroxides which are formed during lipid peroxidation from cellular membrane, such elevation of heptatic GSH-Px activity may contribute to the improvement of antioxidative effects under oxidative damage in the liver.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.529-538
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• 1995

It has been believed that the increased release of free oxygen radicals ($O_2^-,H_2O_2$, and $OH^-$) might be a factor in the pathogenesis of periodontal diseases. Antioxidant enzymes such as glutathione peroxidase(GSH-PX) and catalase can protect the tissue damage from the $H_2O_2$. In order to investigate the GSH-PX and catalase activity in the blood plasma and red blood cells(RBCs) of the patients with periodontitis, 19 patients who had good general health, attachment loss more than 6 mm and bone loss were selected as periodontitis group, 7 patients who had severely inflamed gingiva were selected as gingivitis group, and 15 volunteers with good general and periodontal health were selected as normal group. 17 of 26 patients were performed scaling and root planing to reduce the gingival inflammation for gingivitis and periodontitis groups, and were selected as posttreatment group. After blood plasma and RBCs were collected and separated 1 ml of peripheral blood from each subject, GSH-PX activity in blood plasma and RBCs was measured by the same method that Stefan et al. did, and catalase activity in RBCs was measured by the same method that Beers et al. did. The difference of GSH-PX and catalase activity between normal, gingivitis, and periodontitis groups was statistically analyzed by ANOVA with SPSS/PC+ program, and the difference between pretreatment and posttreatment groups was analyzed by Student t-test. The results were as follows : 1. GSH-PX activity in blood plasma was significantly lower in the gingivitis group($0.8683{\pm}0.0658$), periodontitis group($0.7130{\pm}0.1333$) than in the normal group($1.0241{\pm}0.0801$)(p<0.05), and GSH-PX activity in RBCs was significantly lower in the gingivitis groupt. $0.8156{\pm}0.1167$), periodontitis group($0.7533{\pm}0.1185$) than in the normal group($l.1963{\pm}0.2044$)(P<0.05), but there was no statistical significance in the difference of GSH-PX activity in RBCs between the gingivitis group and periodontitis group(p>0.05). 2. Catalase activity in RBCs was siginficantly lower in the periodontitis group($117.34{\pm}35.01$) than in the normal group($l52.38{\pm}32.09$)(p<0.05). 3. GSH-PX activity in blood plasma was significantly increased in the posttreatment groupe $1.0376{\pm}0.2820$) compared to the pretreatment group(0.7608 0.1600) (p<0.05), and GSH-PX activity in RBC was significantly increased in the posttreatment group($1.0421{\pm}0.2330$) compared to the pretreatment group($0.7728{\pm}0.1210$)(p<0.05). 4. There was no statistical significance in the difference of catalase activity in RBCs between the pretreatment group($112.04{\pm}43.65$) and posttreatment group($l33.41{\pm}39.16$)(p>0.05).The results, within the limits of the present experiment, suggest that the lowered activity of GSH-PX and catalase in blood plasma and RBCs may be related with periodontopathogenesis.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.146-152
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• 2005

The objective of present study was to investigate the effect of onion extracts on mercuryinduced cytotoxicity, lipid peroxidation and antioxidant enzyme activities in primary monolayer cultures of rat hepatocytes. Primary cultures of rat hepatocytes were incubated for 6 hr in the presence of various concentrations (0, 1, 5, 10, 30 or 50 ppm) of $HgCl_2$. Cytotoxicity and cell viability were determined by measuring glutamic oxaloacetic transaminase (GOT) activity, lactate dehydrogenase (LDH) activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) value. Lipid peroxidation w as evaluated using thiobarbituric acid reactive substances (TBARS) assay. Effects of onion extract on antioxidant system were determined by measuring catalase, glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rd) activities as well as DPPH free radical scavenging activity. $HgCl_2$ at the concentration of 10 ppm increased GOT activity and TBARS concentration but decreased %MTT reduction, whereas $HgCl_2$ at the concentration of 30 ppm increased LDH activity, representing that $HgCl_2$ caused cytotoxicity and lipid peroxidation in dose-dependent manner, $HgCl_2$ at the concentration of 30 ppm significantly decreased catalase, GSH-Px and GSH-Rd activities. When primary cultures of rat hepatocytes were incubated with various concentrations (0, 0.01, 0.05, 0.1 or 0.3 mg/ml) of onion extract for 6 hr in the presence of 30 ppm of $HgCl_2$, onion extracts at the concentration of 0.05 mg/ml decreased GOT activity, but increased %MTT reduction by 30 ppm of $HgCl_2$. $HgCl_2-induced$ LDH activity and TBARS concentration were decreased by onion extract at the concentration of 0.01 mg/ml. Taken together, onion extract prevented H$HgCl_2-induced$ hepatocyte injury and lipid peroxidation. Onion extracts at the concentration of 0.1 mg/ml almost or completely inhibited $HgCl_2-induced$ catalase and GSB-Px activities. GSH-Rd activity, however, was not affected by onion extract. Free radical scavengjing activity was increased as concentration of onion extract increased. Onion extract at the concentrion of 5 mg/ml possesed mote than 93% scavenging activity comparing to 100% radical scavenging activity by pyrogallol solution as a reference. These results demonstrate that onion extracts suppressed mercury-induced cytoctoxicity and lipid peroxidation by scavenging free radical and increasing catalase and GSH-Px activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1159-1165
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• 2006

Our preliminary study showed that genistein and daidzein improved blood glucose level in type 2 diabetic mice by enhancing the glucose and lipid metabolism. The objective of this study was to evaluate whether genistein and daidzein are associated with alterations in antioxidant defense mechanism of type 2 diabetic mice. Male C57BL/KsJ-db/db (db/db) mice and age-matched non-diabetic littermates (db/+) were used in this study. The db/db mice were divided into control, genistein (0.02%, w/w) and daidzein (0.02%, w/w) groups. The relative weights of liver, epididymal adipose tissue and perirenal adipose tissue were significantly higher in the db/db group than in the db/+ group, whereas heart weight was lower. The genistein and daidzein supplement did not affect the organ weights in db/db mice. The blood glucose level was positively correlated with superoxide dismutase (SOD, r=0.380, p<0.05) and catalase (CAT, r=0.345, p<0.05) activities and negatively correlated with glutathione peroxidase (GSH Px, r= 0.404, p<0.05) activity in erythrocyte. Therefore, the erythrocyte SOD and CAT activities were significantly elevated in the db/db group compared to the db/+ group and the GSH-Px activity was lowered. However, the supplementation of genistein and daidzein reversed erythrocyte CAT and GSH-Px activities in type 2 diabetic mice. In this current study, the SOD activities in liver, kidney and heart were significantly not different between the groups. The CAT and GSH-Px activities in liver and GSH-Px activity in kidney were significantly higher in the db/db group than in the db/+ group, while the CAT activity in kidney, CAT and GSH-Px activities in heart were lowered. The supplementation of genistein and daidzein significantly attenuated the changes of CAT and/or GSH-Px activities in liver and heart. The supplementation of genistein and daidzein elevated GSH levels in kidney and heart compared to the db/db control group. The lipid peroxide levels in liver, kidney and heart were significantly lowered in the genistein and daidzein supplemented groups compared to the db/db control group. These results suggest that genistein and daidzein might be beneficial for the prevention of type 2 diabetic complication via suppressing changes of antioxidant enzymes activities with simultaneous reduction of lipid peroxidation.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1253-1257
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• 2009

Exo-polysaccharide isolated from the culture of Grifola frondosa was modified by sodium periodate ($NaIO_4$) and sodium chlorite ($NaClO_2$) to delete polysaccharide part and phenolic compound, respectively, and was investigated what effect has each part of exo-polysaccharide against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress in porcine kidney epithelial cells (LLC-PK1). Oxidative stress on LLC-PK1 cell was measured by cell viability, lipid peroxidation, superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) activity. Exposure of LLC-PK1 cells to 1 mM AAPH for 24 hr resulted in significant decrease in cell viability, SOD, and GSH-px action, and significant increase in lipid peroxidation. The treatment of exo-polysaccharide and $NaIO_4$ modified sample protected LLC-PK1 cells from AAPH-induced cell damage such as cell viability, lipid peroxidation, SOD, and GSH-px activity in a dose dependant manner (10, 100, and $500{\mu}g/mL$). However, the treatment of $NaClO_2$ modified sample did not affect for cell viability, lipid peroxidation, SOD, and GSH-px activity. The antioxidant activity of exo-polysaccharide was significantly decreased on AAPH-induced LLC-PK1 cell system when phenolic compound was deleted. The antioxidant activity was significantly correlated with the content of phenolic compound of exo-polysaccharide.

• Nutrition Research and Practice
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• v.16 no.4
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• pp.464-475
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• 2022

BACKGROUND/OBJECTIVES: Increased levels of uremic toxins and decreased antioxidant capacity have a significant impact on the progression of chronic kidney disease (CKD). However, it remains unclear whether they interact with each other to mediate the damage of kidney function. The purpose of this study was to investigate whether uremic toxins (i.e., homocysteine and indoxyl sulfate [IS]), as well as glutathione-dependent antioxidant enzyme activities are dependently or independently associated with kidney function during different stages of CKD patients. SUBJECTS/METHODS: One hundred thirty-two patients diagnosed with CKD at stages 1 to 5 participated in this cross-sectional study. RESULTS: Patients who had reached an advanced CKD stage experienced an increase in plasma uremic toxin levels, along with decreased glutathione peroxidase (GSH-Px) activity. Plasma homocysteine, cysteine, and IS concentrations were all positively associated with each other, but negatively correlated to GSH-Px activity levels after adjusting for potential confounders in all CKD patients. Although plasma homocysteine, cysteine, IS, and GSH-Px levels were significantly associated with kidney function, only plasma IS levels still had a significant association with kidney function after these parameters were simultaneously adjusted. In addition, plasma IS could interact with GSH-Px activity to be associated with kidney function. CONCLUSIONS: IS plays a more dominant role than homocysteine and GSH-Px activity in relation to kidney function.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.799-810
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• 2004

This study was conducted to determine effects of spent composts of Se-enriched mushrooms (Se-SMC) as the dietary selenium source on carcass characteristics, plasma glutathione peroxidase(GSH-Px) activity and Se deposition in finishing Hanwoo steers. In combination with both Se-SMC and normal SMC, experimental treatment diets were formulated to contain 0.1, 0.3, 0.6 and 0.9 ppm of Se on a dry matter basis. A total of 20 finishing Hanwoo steers (average BW = 613 kg, average age = 20 to 24 mo) were allotted to treatments in four groups of five steers per pen for 12 wk preceding slaughter. While the experiment is employed, blood samples were taken to analyze Se concentration and GSH-Px activity, and muscle and liver samples were collected for analyses of Se contents in their tissues after slaughter. DMl and BW gain were not affected by dietary Se level and any toxic symptoms in treatments with a higher level of Se were not observed. No differences were noted for carcass characteristics. Se concentration in whole blood and plasma GSH-Px activity were linearly increased with the increasing level of dietary Se (P < 0.01). Se content in the hind leg for Se-SMC supplemented groups significantly increased (P < 0.05) upon dietary Se level, with 0.27, 0.37, 0.40 and 0.46 !1g1g dry, respectively. However, Se content in the loin was not affected by dietary Se levels. Se content in the liver was significantly increased(P < 0.05) as dietary Se increased, with 0.79, 1.40, 2.39 and 3.10 !1g1g dry, respectively. These results suggested that Se in the Se-SMC was highly bioavailable, and Se-SMC might be used not only as an inexpensive way of providing Se for ruminants but also as another way of producing Se-fortified beef.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1254-1262
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• 1998

This study has done to investigate the relationship between the icreased lipid oncentration caused by smoking and plama levels of vitamin A and vitamin E, antiodative enzyme activity, and lipid peroxidation , in 52 male smokers and 32 non-smokers, Dietary vitamin A and vitamin E intake was imilar in both smokers and non-smokers. Absolute plasma concentrations of vitamin A and vitamin E were not significantly different between two groups, whereas vitamin E/cholesterol ration in plasma was low or in smokers than in that of non-smokers(p<0.05). It was considered that this lowered effect was due to the elevated plasma lipid concentration rather than oxidant stress derived from smoking, in view of the fact that smokers had higher cholesterol (15.2%) adn LDL-C(26.6%) levels than non-smokers. In non-smokers, plasma thiobarbiturin acid reactive substances(TBARS) conrrelated positively with total cholesterol(r=0.63466, p<0.001), LDL-C level(r=0.57166, p<0.01) , and LDL-C/HDL-C ratio(r=0.45926, p<0.05) . Activities of glutathione perosidase(GSH-Px) , superoside dismutase(SOD), and catalse made no difference in both groups. However, it was observed in non-smokers that GSH-Px activity had negative correlations with total cholesterol(r=-0.67293, p<0.001), LDL-C level(r=-0.62878, p<0.001), and LDL-C/HDL-C ratio (r=-0.58824, p<0.01), indicating that there was a dependent relationship between lipid perosidation and plasma lipid level. The smokers also showed negative correlations for GSH-Px activity with total cholesterol (r=-0.29946, p<0.05) and LDL-c level (r=0.45914, p<0.001), and LDL-C/HDL-c ratio(r=-0.35438, p<0.05). It seemed that the lipid that the lipid level elevated by sustaines smoking resulted in reducing vitamin E/cholesterol ratio and proportion of antioxidant to oxidant load, and then GSH-Px activity, with insufficient removal of free radicals(TBARS 2.43$\pm$0.51 and 1.81$\pm$0.15nmol/ml in smokers and non-smokers, respectively). These findings suggest that higher plasma lipid levels may play a more important role in perturbing the antioxidant defense system including vitamin E status and GSH-Px activity, at least in circumstances that increase lipid concentration . In addition, in exposure to free radicals like those in cigarette smoke. In those cases the ratio of vitamin E/lipid in plasma can be a more indicator of vitamin E status than plasma levels of vitamin E alone.

• Korean Journal of Environmental Agriculture
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• v.22 no.2
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• pp.94-99
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• 2003

The objective of present study was to investigate the antioxidative and hepatoprotective effects of selenium on cadmium-induced toxicity and lipid peroxidation in rat hepatocyte primary culture. To do this, two separate experiments were conducted. In Experiment 1, primary cultures of rat hepatocytes were incubated for 6 hr in the presence of various concentrations (1, 10, 50, 100, and $500\;{\mu}M$) of cadmium chloride. Cytotoxicity and lipid peroxidation were evaluated using the MTT assay and TBARS assay, respectively. Antioxidative and hepatoprotective effects were determined by measuring the activity of GOT and GSH-Px, respectively. Cell viability was reduced and lipid peroxidation was increased by cadmium in dose-dependent manners. There was significantly negative correlation (r=-0.943, p<0.01) between cell viability and lipid peroxidation GOT activity was increased and GSH-Px activity was decreased by cadmium at the concentration of $50\;{\mu}M$. In Experiment 2, primary cultures of rat hepatocytes were incubated for 6hr in the presence of 100\;{\mu}M$ of cadmium chloride and various concentrations (0.01, 0.1 and 1 ppm) of sodium selenite to assess the effect of selenium on cadmium-induced toxicity and lipid peroxidation. Cell viability and GSH-Px activity were increased by sodium selenite at the concentration of 1 ppm Whereas, lipid peroxidation and GOT activity were reduced by 0.1 ppm of sodium selenite. These results demonstrate that selenium has an antioxidative and hepatoprotective potentials against cadmium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.116-126
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• 1993

The purposes of this study were to investigate the effect of seleniumc (Se) and vitamin E on activity of enzyme relevant to lipid peroxidation in alcohol administrated rats. Seventy two male rats of Sprague-Dawley strain weighing about 58~62g were divided into 12groups. The dietary Se levels were 0, 0.4 and 10mg and the dietary vitamin E levels were 0 and 150mg per kg diet, respectively. Alcohol-administrated groups received drinking water solution containing 10% of ethanol from the 3-weeks of experimental periods. The obtained experimental results are summarized as follow: The ${\gamma}$-GTP activity in plasma was higher in alcohol administrated groups and high selenium group (HSe) and low selenium group (LSe) than in control groups (CSe). The ${\gamma}$-GOT and GPT activities were higher in alcohol groups. The ${\gamma}$-GTP activity was significantly influenced by alcohol in LSe groups than in other groups. The glutathione peroxidase (GSH-Px) activity of plasma was significantly lower in LSe groups than HSe and CSe groups. The GSH-Px activity of microsomal and cytosolic fraction was slightly lower in alcohol groups and was about a half value lower in HSe and LSe groups than CSe groups. There was negative correlation between plasma Se level and GSH-Px activity of cytosolic fraction in HSe groups (r=- 0.662, p<0.001) and positive correlation in LSe groups (r=0.640, p<0.001). The GSH S-transferase activity in microsomal and cytosolic fraction was slightly higher in alcohol administrated but vitamin E nonadministrated groups, and significantly higher in LSe groups than in other groups. The catalase activity in mitochondria was lower in HSe than CSe groups, but rather higher in LSe groups. The superoxide dismutase (SOD) activity in cytosolic fraction of liver was not found any effect in all groups. The cytochrome P-450 was higher in alcohol groups, but significantly lower in HSe groups. In conclusion, the deficiency of Se and vitamin E develops the hyperoxidation of liver lipid through the increase of activity of enzyme related to the lipid peroxidation and alcohol administration appears to further increase of hyperoxidation of liver lipid.