• Nutrition Research and Practice
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• v.9 no.3
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• pp.227-234
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• 2015

BACKGROUND/OBJECTIVES: We investigated the effects of a combination of grape pomace (Vitis labrusca, Campbell Early) and Omija fruit (Schizandra chinensis, Baillon) ethanol extracts on lipid metabolism and antioxidant defense system in diet-induced obese mice. MATERIALS/METHODS: Forty male C57BL/6J mice were divided into four groups and fed high-fat diet (control group, CON) or high-fat diet added 0.5% grape pomace extract (GPE), 0.05% Omija fruit extract (OFE) or 0.5% GPE plus 0.05% OFE (GPE+OFE) for 12 weeks. RESULTS: In contrast to the GPE- or OFE-supplemented groups, the GPE+OFE group showed significantly lower body weight and white adipose tissue weights than the CON group. Moreover, GPE+OFE supplementation significantly decreased plasma total cholesterol and increased the plasma HDL-cholesterol/total-cholesterol ratio (HTR) compared to the control diet. The hepatic triglyceride level was significantly lower in the GPE+OFE and GPE groups by increasing ${\beta}$-oxidation and decreasing lipogenic enzyme compared to the CON group. Furthermore, GPE+OFE supplementation significantly increased antioxidant enzyme activities with a simultaneous decrease in liver $H_2O_2$ content compared to the control diet. CONCLUSIONS: Together our results suggest that supplementation with the GPE+OFE mixture may be more effective in improving adiposity, lipid metabolism and oxidative stress in high-fat diet-fed mice than those with GPE and OFE alone.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.26-32
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• 2016

BACKGROUND/OBJECTIVES: It has been shown that vitamin A supplementation has different effects on skeletal health and the antioxidant system. Deficiency or excess of this vitamin can lead to health problems. Vitamin A can work as either an antioxidant or prooxidant depending on its concentration. The present study was conducted to investigate the effects of different doses of vitamin A supplementation on the antioxidant system in rats. MATERIALS/METHODS: Forty Spargue-Dawley male rats were divided into four groups according to the dose of vitamin A received: 0 (A0), 4,000 (A1), 8,000 (A2), and 20,000 (A3) IU retinyl palmitate/kg diet. After a feeding period of 4 wks, lipid peroxide levels, glutathione concentration, antioxidant enzyme activities, and vitamins A and E concentrations were measured. Histopathological changes were observed in rat liver tissue using an optical microscope and transmission electron microscope. RESULTS: Lipid peroxide levels in plasma were significantly decreased in the A1 and A2 groups compared to the A0 rats. Erythrocyte catalase and hepatic superoxide dismutase activities of the A2 group were significantly higher than those of the A0 group. Hepatic glutathione peroxidase activity was significantly lower in the A3 group compared to the other groups. Total glutathione concentrations were significantly higher in the A1 and A2 groups than in the A0 group. Histological examination of liver tissue showed that excessive supplementation of vitamin A might lead to lipid droplet accumulation and nuclear membrane deformation. CONCLUSIONS: These results indicate that appropriate supplementation of vitamin A might have a beneficial effect on the antioxidant system in rats.

• Toxicological Research
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• v.22 no.1
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.191-195
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• 2009

We assessed the effect of surimi gel, which is prepared from the king oyster mushroom (pleurotus eryngii) and cuttlefish meat paste (KCP) on lipid metabolism and antioxidant activity in high-cholesterol-fed rats. Three groups of 3-week-old male Sprague-Dawley rats were fed on a diet containing 1 g cholesterol/kg for 6 weeks. We administered only a high-cholesterol diet to the control group, one group was fed on surimi gel containing cuttlefish paste and king oyster mushrooms, and another group was fed with general boiled fish meat paste (GFP), which is commonly sold in marketplaces. Plasma and hepatic lipid profiles were measured, and the antioxidant status of the liver was assessed. The plasma triglyceride concentration did not differ significantly among the groups. Supplementation with KCP resulted in lower plasma and hepatic cholesterol concentrations and atherogenic index as compared to the control group and GFP, whereas the plasma high-density lipoprotein-cholesterol concentration was elevated. Moreover, the KCP-supplemented animals evidenced greater bile acid excretion. The KCP groups evidenced significantly lower plasma and hepatic levels of thiobarbituric acidreactive substances as compared to the control group. Besides, hepatic antioxidant enzyme activities, including catalase and superoxide dismutase, were significantly higher in the KCP group. In conclusion, KCP was quite effective in improving the lipid metabolism and reducing oxidative stress by upregulating the hepatic antioxidant enzymes in high-cholesterol-fed rats.

• Journal of Nutrition and Health
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• v.31 no.5
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• pp.906-913
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• 1998

This study an analyzes the effects of the P/S ratio of dietary lipids and antioxidant vitamin supplements on serum lipids level and fatty acid profile, the degree of lipid peroxidation, and the antioxidant enzyme activities in the liver of rats treated with 7,12-dimethylbenz($\alpha$) anthracene(DMBA). P/S ratio of dietary lipids was made into 0.5, 1 and 2 by mixing palm oil, soybean oil, sesame oil and perilla oil at 10%(w/w) fat level and n-6/n-3 ratio was fixed to 4. Antioxidant vitamin of $\alpha$-tocopherol or $\beta$-carotene was supplemented in addition to vitamin mixture which was given at 1 % of the standard diet. female Sprague-Dawley strain rats, about 60 days old, were divided into three groups(LP : low P/S ratio(0.5), MP : medium P/S ratio (1.0), HP , high P/S ratio(2.0)) and each group was sub-divided into three groups(S ; standard, T ; tocopherol supplemented, C : carotene supplemented): Two weeks after feeding experimental diets, all groups were treated with a single dose of DMBA(2mg/100g BW) by gastric intubation and fed experimental diet for 9 week. The results were as follows ; 1) Serum total cholesterol(TC) level was not significantly influenced by diet but tended to be lower in HP groups compared to LP and MP groups. Triglyceride level was the highest in LP groups and the lowest in $\alpha$-tocopherol supplemented groups. 2) Thiobarbituric acid reactive substance(TBARS) level, representing lipid peroxidation in hepatic microsome, tended to be increased as the unsaturation of dietary lipids increases. $\alpha$-Tocopherol supplement significantly decreased TBARS level. 3) The activities of superoxide dismutase(SOD) and glutathione peroxidase(GSHPx) in hepatic cytosol showed the tendency to be high with increasing P/S ratio of dietary lipids. SOD activity was not significantly influenced by antioxidant vitamin, but GSHPx activity was significantly increased in $\alpha$-tocopherol supplemented groups. In summary, high polyunsaturated fat diet was effective on reducing the serum level of total cholesterol and triglyceride, while it increased unsaturation and peroxidizability of serum fatty acid. With increasing P/S ratio of dietary lipids, lipid peroxidation was increased in the liver and antioxidant enzyme system was induced to inhibit lipid peroxidation against oxidative damage. $\alpha$-Tocopherol supplement was effective in lowering lipid peoxidation, but $\beta$-carotene supplement did not exhibit antioxidant effect. (Korean J Nutrition 31(5) 906~913, 1998)

• Journal of Nutrition and Health
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• v.29 no.2
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• pp.232-241
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• 1996

This study was designed to compare the effect of different dietary fats on plasma lipids, the degree of lipid peroxidation and the activity of antioxidant enzymes in RBC and liver rats treated with or wighout 1, 2-dimethylhydrazing (DMH). Male Sprague Dawley rats, at 7 weeks-old, were divided into control and DMH-treated grous, and each group was again subdivided into four were perilla oil (PO), blend fat (BF) containing ten different kinds of dietary oil, beef tallow (BT), corn oil (CO). At the same time, each rat was injected intramusculary with saline(for control) or DMH twice a week for 6 weeks to give total dose of 180 mg/kg body weight. Compared with BT feeding, BF reduced plasma total choesterol level and PO and Co reduced plasma TG levels (p<0.05). DMH injection decreased plasma cholesterol in all dietary groups. However, PO decreased tocopherol levels and increased TBARS levels in RBC compared to BT. The degree of hemolysis in PO group was higher than that of BT group (p<0.05 only in control group. Fatty acid composition of hepatic microsome was reflected by dietary fatty acid profile. The peroxidizability index and TBARS level in hepatic micorsome were significantly increased but tocopherol level was lowered in PO group compared to BT group. Activites of superoxide dismutase and glutathione peroxidase in RBC and hepatic cytosol were not influenced y dietary fats and DMH treatment(p<0.05). Overall, perilla oil rich in $\omega$3 $\alpha$-linolenic acid could be a very important dietary source in reducing plasma lipids and blend fat was also good dietary oil mixture in reducing plasma cholesterol. However, the degree of lipid peroxidation was greater in tissue by perilla oil feeding and it is very difficult to use only perilla oil as oil source for meal preparation, so that it could be suggested to use more perilla oil and fish to give an equal effect of blend fat in order to reduce the risk factors against cardiovascular disease.

• Nutrition Research and Practice
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• v.18 no.1
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• pp.46-61
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• 2024

BACKGROUND/OBJECTIVES: An increasing life expectancy in society has burdened healthcare systems substantially because of the rising prevalence of age-related metabolic diseases. This study compared the effects of animal protein hydrolysate (APH) and casein on metabolic diseases using aged mice. MATERIALS/METHODS: Eight-week-old and 50-week-old C57BL/6J mice were used as the non-aged (YC group) and aged controls (NC group), respectively. The aged mice were divided randomly into 3 groups (NC, low-APH [LP], and high-APH [HP] and fed each experimental diet for 12 weeks. In the LP and HP groups, casein in the AIN-93G diet was substituted with 16 kcal% and 24 kcal% APH, respectively. The mice were sacrificed when they were 63-week-old, and plasma and hepatic lipid, white adipose tissue weight, hepatic glucose, lipid, and antioxidant enzyme activities, immunohistochemistry staining, and mRNA expression related to the glucose metabolism on liver and muscle were analyzed. RESULTS: Supplementation of APH in aging mice resulted in a significant decrease in visceral fat (epididymal, perirenal, retroperitoneal, and mesenteric fat) compared to the negative control (NC) group. The intraperitoneal glucose tolerance test and area under the curve analysis revealed insulin resistance in the NC group, which was alleviated by APH supplementation. APH supplementation reduced hepatic gluconeogenesis and increased glucose utilization in the liver and muscle. Furthermore, APH supplementation improved hepatic steatosis by reducing the hepatic fatty acid and phosphatidate phosphatase activity while increasing the hepatic carnitine palmitoyltransferase activity. Furthermore, in the APH supplementation groups, the red blood cell (RBC) thiobarbituric acid reactive substances and hepatic H₂O₂ levels decreased, and the RBC glutathione, hepatic catalase, and glutathione peroxidase activities increased. CONCLUSIONS: APH supplementation reduced visceral fat accumulation and alleviated obesity-related metabolic diseases, including insulin resistance and hepatic steatosis, in aged mice. Therefore, high-quality animal protein APH that reduces the molecular weight and enhances the protein digestibility-corrected amino acid score has potential as a dietary supplement for healthy aging.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.658-665
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• 2007

Phyllostachys pubescens (Maengiong-Juk), a kind of the bamboo, was reported to have many beneficial pharmacological actions. in this study, of using 70% ethanol extract of Phyllostachys pubescens we investigated its efficacy on angiotensin converting enzyme (ACE) and antioxidant enzyme activities. In addition, vasorelaxant effect was examined in rat aortic rings. The inhibitory effect of ACE activity by Phyllostachys pubescens extract (PPE) was dose-dependently increased by 61.42% at 10mg/ml. PPE relaxed the pre-contracted rat aortic rings with 10$^{-6}$M phenylephrine, showing about 88% at 4.0mg/ml. Sprague Dawley (SD) rats were given different concentrations of PPE mixed in the drinking water for 10 weeks. PPE did not show any difference with control group in blood pressure, body weight (BW) and food intake. However, it revealed the highest total antioxidative effect at dose of 1.0 g/100 g BW in plasma by TEAC assay. Thiobarbituric acid reactive substance (TBARS) and protein carbonyl levels which are markers of tissue peroxidation, were significantly lowed at the same dosage. Furthermore, hepatic antioxidant enzymes such as total superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and catalase activities were also significantly increased by PPE (1.0 g/100 g BW). In conclusion, we suggest that PPE might have antihypertensive effect through increasing antioxidant activities.

• Journal of Ginseng Research
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• v.36 no.3
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• pp.248-255
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• 2012

Potential antioxidant effect of processed ginseng (sun ginseng, SG) on oxidative stress generated by tert-butyl hydroperoxide (t-BHP) was investigated in HepG2 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase (LDH) leakage test demonstrated that SG dose-dependently prevents a loss of cell viability against t-BHP-induced oxidative stress. Also, SG treatment dose-dependently relieved the increment of activities of hepatic enzymes, such as aspartate aminotrasferase and alanine aminotransferase, and lipid peroxidation mediated by t-BHP treatment in HepG2 cells. SG increased the gene expression of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. However, high dose of SG treatment caused decrease in mRNA level of glutathione peroxidase as compared to low dosage of SG-treated cells. The gene expression of glutathione reductase was found to be slightly increased by SG treatment. In addition, SG extract attributed its hepaprotective effect by inducing the mRNA level of bcl-2 and bcl-xL but reducing that of bax. But, the gene expression of bad showed no significant change in SG-treated HepG2 cells. These findings suggest that SG has hepatoprotective effect by showing reduction of LDH release, activities of hepatic enzymes and lipid peroxidation and regulating the gene expression of antioxidant enzymes and apoptosis-related molecules against oxdative stress caused by t-BHP in HepG2 cells.

• Animal Bioscience
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• v.35 no.6
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• pp.938-947
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• 2022

Objective: The beneficial effects of glycine were tested in piglets with diquat-induced hepatic injury. Methods: Thirty-two piglets were assigned by a 2×2 factorial experimental design including glycine supplementation and diquat challenge. After 3 weeks of feeding with a basic diet or a 1% glycine supplemented diet, piglets were challenged with diquat or saline. After 1 week later, the piglets were slaughtered and samples were collected. Results: Our results indicated that glycine alleviated diquat induced morphological hepatic injury, decreased the activities of plasma alanine aminotransferase, aspartate aminotransferase and glutamyl transpeptidase in the piglets under diquat challenge, and increased total antioxidant capacity and antioxidative enzyme activity significantly. Adding glycine enhanced the concentrations of hepatic adenosine triphosphate and adenosine diphosphate. Transmission electron microscope observation showed that diquat induced clear hepatocytes ferroptosis and its effect could be alleviated by glycine to a certain degree. Moreover, glycine significantly affected mRNA and protein expression of ferroptosis-related signals in the liver. Conclusion: These results demonstrated that glycine attenuated liver damage via inhibiting ferroptosis.