• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.311-318
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• 2022

Salicylic acid (SA), a phenolic compound, plays a pivotal role in regulating a wide range of physiological and metabolic processes in plants such as antioxidant cellular defense, photosynthesis, and biotic and abiotic stress responses during the growth and development. We examined the effect of exogenous SA application (100 mg·L^-1) on the growth, yield, photosynthetic characteristics, lipid peroxidation, and antioxidant enzyme activity of chili pepper plants under high temperature and drought stress conditions. SA treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde and H₂O₂ were significantly lower in the third treatment of SA compared to the control. The activity of ascorbate peroxidase, catalase, peroxidase and superoxide dismutase, increased in treated plants by up to 247, 318, 55 and 54%, respectively compared to the nontreated control. There was no significant difference in the growth characteristics between SA-treated and nontreated plants, while the SA treatment increased marketable yield (kg/10a) by about 15% compared to the nontreated control. Taken together, these results suggest that foliar application of SA alleviates physiological damages caused by the combination of drought and heat stress, and enhances the photosynthetic capacity and antioxidant enzyme activities, thereby improving tolerance to a combination of water deficit and heat stress in chili pepper plants.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1163-1174
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• 2021

Casein-derived antioxidant peptides by using microbial proteases have gained increasing attention. Combination of two microbial proteases, Protin SD-NY10 and Protease A "Amano" 2SD, was employed to hydrolyze casein to obtain potential antioxidant peptides that were identified by LC-MS/MS, chemically synthesized and characterized in a oxidatively damaged HepG2 cell model. Four peptides, YQLD, FSDIPNPIGSEN, FSDIPNPIGSE, YFYP were found to possess high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability. Evaluation with HepG2 cells showed that the 4 peptides at low concentrations (< 1.0 mg/ml) protected the cells against oxidative damage. The 4 peptides exhibited different levels of antioxidant activity by stimulating mRNA and protein expression of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as nuclear factor erythroid-2-related factor 2 (Nrf2), but decreasing the mRNA expression of Kelch-like ECH-associated protein 1 (Keap1). Furthermore, these peptides decreased production of reactive oxygen species (ROS) and malondialdehyde (MDA), but increased glutathione (GSH) production in HepG2 cells. Therefore, the 4 casein-derived peptides obtained by using microbial proteases exhibited different antioxidant activity by activating the Keap1-Nrf2 signaling pathway, and they could serve as potential antioxidant agents in functional foods or pharmaceutic preparation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.570-576
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• 2013

The purpose of this study was to investigate the effect of turmeric on antioxidative systems and oxidative damage in rats fed a high fat and cholesterol diet. A total 40 rats were divided into four experimental groups: a normal diet group (N), a high fat and cholesterol diet group (HF), a high fat and cholesterol diet group supplemented with 2.5% turmeric powder (TPA group) and a high fat and cholesterol diet group supplemented with 5% turmeric powder (TPB group). The serum glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activity of the turmeric supplemented groups were decreased compared to the HF group. The GPT activity of the TPB group was especially and significantly decreased compared to the HF group. Hepatic superoxide dismutase (SOD) of the TPB group was significantly increased compared to the HF group. However, there were no significant differences in the activities of hepatic glutathione peroxidase (GSHpx) and catalase (CAT) among all experimental groups. Hepatic glutathione S-transferase (GST) activity in the TPA and TPB groups were increased compared to the HF group. Hepatic superoxide radical content in mitochondria of the 5% turmeric supplemented group was significantly decreased compared to the HF group. Hepatic hydrogen peroxide content in the cytosol and mitochondria of the turmeric-supplemented groups were decreased compared to the HF group. Hepatic carbonyl values in the mitochondria of the turmeric supplemented groups were significantly decreased compared to the HF group. Thiobarbituric acid reaction substance (TBARS) values in the liver were significantly reduced in turmeric supplemented groups compared to the HF group. These result suggest that turmeric powder may reduce oxidative damage through the activation of antioxidative defense systems in rats fed high fat and cholesterol diets.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1506-1515
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• 2009

This study was performed to investigate the effect of chongkukjang intake on lipid metabolism and liver function in alcoholic fatty liver rats. Thirty-five 7-weeks old Spargue-Dawley male rats were used as experimental animals. After inducing alcoholic fatty liver, rats were divided into two groups and fed ethanol＋casein diet (ECD) or ethanol＋chongkukjang diet (EChD). At 10th, 20th and 30th days of the feeding experimental diet, rats were sacrificed to get blood and liver samples for analysis of blood lipids, lipid peroxides, antioxidative enzymes and biochemical indices of liver function. The mean food intake was not significantly different between ECD and EChD groups. Daily weight again of EChD group was significantly higher than that of ECD group at days 20 and 30. Serum total lipid, triglyceride and total cholesterol of ECD group were significantly higher than those of EChD group, while HDL-cholesterol was significantly higher in EChD group. Liver TBARS level of ECD group was significantly higher than that of EChD group. However, liver conjugated diene level was significantly higher in ECD group only at day 10. SOD, CAT and GPx activities of EChD group were significantly higher than those of ECD group at days 20 and 30. In the indices of liver function, GOT and GPT of ECD group were significantly higher than those of EChD group at day 10. LDH was significantly higher in ECD group. γ-GTP was significantly higher in ECD group only at day 20. Serum alcohol concentration of ECD group was significantly higher than that of EChD group at day 30. ADH and ALDH activities of EChD group were significantly higher than those of ECD group at day 30. Therefore, chongkukjang intake seems to give a beneficial effect on improving lipid metabolism and liver function by increasing HDL-cholesterol level, antioxidative enzyme activites, alcohol enzyme activities and decreasing serum lipids, liver TBARS and conjugated diene.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.384-389
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• 2014

The objective of the present study was to investigate the chemical composition of anthocyanin-enriched extract of radiation-induced blackberry (Rubus fruticosus L.) mutant (${\gamma}$-B201) as well as the protective effect of ${\gamma}$-B201 against oxidative stress in vitro. The cytotoxicity, reactive oxygen species (ROS) scavenging capacity, and DNA damage were assessed by WST-1 assay, flow cytometry, and comet assay, respectively. Lactate dehydrogenase, superoxide dismutase, and catalase activities were determined by using a commercial kit. The in vitro results showed that ${\gamma}$-B201 increased the cell viability, reduction of lactate dehydrogenase release, and intracellular ROS scavenging capacity in hydrogen peroxide ($H_2O_2$)-treated HepG2 cells. Furthermore, treatment with ${\gamma}$-B201 attenuated DNA damage in $H_2O_2$-treated HepG2 cells and treatment with ${\gamma}$-B201 restored the activity of superoxide dismutase and catalase in $H_2O_2$-treated HepG2 cells. In conclusion, the present study suggests that ${\gamma}$-B201 blackberry extract can exert a significant cytoprotective effect against $H_2O_2$-induced cell damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.677-683
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• 2010

This study investigated the effect of young Phragmites communis (Pc) leaves on lipid profiles, lipid metabolism and erythrocyte antioxidant defense system in high-fat diet fed mice. Three groups of mice were fed different diets for 8 weeks: normal diet (Normal), high-fat diet (High-fat; 37% calories from fat) and high-fat diet supplemented with 1% Pc (wt/wt, HF-Pc). Body weight, daily food intake and energy intake tended to decrease by Pc supplement in high-fat fed mice. Pc supplementation significantly lowered plasma triglyceride and total cholesterol concentrations compared to the high-fat control group. Pc also lowered hepatic and heart cholesterol contents, whereas it significantly increased fecal excretion of triglyceride and cholesterol compared to the high-fat control group. Pc significantly inhibited fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and acyl-CoA:cholesterol acyltransferase activities compared to the high-fat control group. Erythrocyte superoxide dismutase and catalase activities were also significantly higher in the high-fat group than in the normal group, however Pc supplementation reversed these changes. The Pc supplementation significantly lowered erythrocyte lipid peroxidation level compared to the high-fat control group. Accordingly, these results suggest that Pc improves lipid metabolism and erythrocyte antioxidant defense system in high-fat diet fed mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1674-1680
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• 2014

The aim of this study was to investigate the protective effects of methanolic extracts of cooked mixed grain rice samples, including grain rice (sorghum, black bean, proso millet, and Job's tears) mixed with fermented brown rice (GR), GR added with 0.5% water extract of Sanghwang mushroom (GRS) or 0.1% curry (GRK), and traditional five grain mixed rice (TMR, Ohgokbap), on $H_2O_2$-induced oxidative injury in LLC-PK1 pig renal epithelial cells. White rice (WR) was used as a positive control. Cells were first exposed to $H_2O_2$ ($250{\mu}M$) for 4 hr, followed by treatment with $100{\mu}g/mL$ of different GR extracts for 24 hr. $H_2O_2$ significantly induced cell damage (P<0.05). Cellular levels of reactive oxygen species (ROS), lipid peroxidation, and antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), were measured. In addition, mRNA levels of antioxidant enzymes were determined by RT-PCR assay. Mixed grain rice, particularly GRS and GRK, were able to reduce cellular levels of ROS, decrease lipid peroxidation, and also increase mRNA expression of antioxidant enzymes compared to other samples. These results suggest that mixed grain rice, specifically GRS and GRK, have strong protective effects against $H_2O_2$-induced oxidative injury in LLC-PK1 cells through inhibition of lipid peroxidation, reduction of ROS levels, and elevation of antioxidant enzyme activities.

• Journal of Nutrition and Health
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• v.48 no.2
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• pp.140-148
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• 2015

Purpose: The purpose of this study was to evaluate the role of coffee in diabetic rats in order to prevent hyperglycemia and hyperlipidemia, and to improve antioxidant enzyme activity in streptozotocin induced diabetic rats. Methods: Thirty two male Sprague-Dawley rats (body weight $200{\pm}5g$) were divided into two groups; diabetic and nondiabetic groups. The groups were each randomly divided into two subgroups; fed control and coffee (5 g coffee powder/kg diet) diets. Diabetes was induced by intramuscular injection of 50 mg streptozotocin/kg body weight. Rats with blood glucose concentrations ${\geq}300mg/dL$ were considered diabetic for these experiments. All rats were fed an experimental diet and deionized water ad libitum for 4 weeks. Results: The results of this study indicate that body weight gain was significantly lower in diabetic groups than in nondiabetic groups regardless of diet. Mean food intake was significantly higher in diabetic groups than in nondiabetic groups, and significantly higher in the coffee group than in the control group in diabetic rats. Food efficiency ratio (FER) was significantly lower in diabetic groups than in nondiabetic groups regardless of diet. The fasting blood glucose of coffee supplemented groups was significantly lower compared with the control group in diabetic and nondiabetic rats. The levels of serum LDL-cholesterol and atherogenic index were significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats, and serum HDL-cholesterol was significantly higher in the coffee group than in control groups. The contents of hepatic triglyceride were significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats. The lipid peroxidation of malondialdehyde (MDA) contents was significantly lower in the coffee group than in the control group in diabetic and nondiabetic rats. Activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase in liver was not significantly different by experimental diets among all groups. Conclusion: In conclusion, effects of 0.5% coffee powder supplemented diet were beneficial on blood glucose and lipids in diabetic rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1716-1726
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• 2012

This study was undertaken to evaluate the antihyperglycemic, antilipid peroxidative, and antioxidant effects of the ethanol extracts of Artemisia iwayomogi (Ai) in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in Sprague-Dawley rats with a single intravenous injection (45 mg/kg b.w.) of STZ. The diabetic rats were then randomized to the diabetic and Ai extract therapy groups which were treated with Ai extract at doses of 1, 2, and 3 g/kg b.w./day, respectively, for 14 days. Oral administration of Ai (2 g/kg b.w.) significantly decreased their intake of food. Dosage of 2 g/kg of the extract significantly decreased blood glucose levels in the glucose level in diabetic rats after 4 day, there was no significant difference observed at 1 and 3 g/kg. A dose of 2 or 3 g/kg of the Ai extract significantly reduced plasma glucose levels in STZ-induced hyperglycemic rats at 7 days. The hypoglycemic effect of Ai at a dose of 2 g/kg was significantly more effective than that of STZ-control. The effect was more pronounced in 2 g/kg than 1 g and 3 g/kg. A significant reduction in triglycerides (TG) and free fatty acids (FFA), and a significant increase in liver glycogen were observed in treated diabetic rats at doses of 2 g/kg after 14 days of treatment. Administration of Ai extracts to diabetic rats showed a significant decrease in liver malondialdehyde (MDA) levels. The activity of superoxide dismutase (SOD) was significantly increased in the 3 g extract-supplemented groups. The activities of glutathione peroxidase (GSH-px) and catalase (CAT) were significantly increased in the 1 g and 3 g extract-supplemented groups. Ai extract significantly increased glutathione-S transferase (GST) activity in a dose-dependent manner compared with treatment in STZ-control rats. Our result supports the fact that the administration of Ai extract is able to reduce hyperglycemia and hyperlipidemia risk, and also reduce the oxidative stress in diabetic rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.161-167
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• 2013

The aim of this study was to investigate the protective effects of methanolic extract from perilla (Perilla frutescens Britt var. japonica) leaves (PLME) on oxidative injury from hydrogen peroxide ($H_2O_2$) in human HaCaT keratinoctyes. Cells were co-incubated with various concentrations (0~200 ${\mu}g/mL$) of PLME for 24 hr, and then exposed to $H_2O_2$ (500 ${\mu}M$) for 4 hr. $H_2O_2$ significantly decreased cell viability (p<0.05). However, PLME provided protection from $H_2O_2$-induced HaCaT cell oxidation in a dose-dependent manner. To further investigate the protective effects of PLME on $H_2O_2$-induced oxidative stress in HaCaT cells, the cellular levels of lipid peroxidation, and antioxidant enzymes (including superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT)) were measured. PLME decreased cellular levels of lipid peroxidation, and also increased the activities of antioxidant enzymes. In addition, the antioxidant activities of PLME were also determined by DPPH and hydroxyl (${\cdot}OH$) radical scavenging assay, and major antioxidant compounds of PLME were measured by colorimetric methods. DPPH and ${\cdot}OH$ radical scavenging activities of PLME increased in a dose dependent manner and was similar to the DPPH scavenging activity of ascorbic acid at 50 ${\mu}g/mL$; however PLME activities were stronger than ascorbic acid (50 ${\mu}g/mL$) in the ${\cdot}OH$ scavenging assay. The amounts of antioxidant compounds, including total polyphenolics, total flavonoids, and total ascorbic acid from PLME were $52.2{\pm}1.1$ mg gallic acid (GAE)/g, $33.7{\pm}4.7$ mg rutin (RUE)/g, and $17.0{\pm}0.5$ mg ascorbic acid (AA)/g, respectively. These results suggest that PLME has a strong free radical-scavenging activity and a protective effect against $H_2O_2$-induced oxidative stress in the keratinocytes.