• BMB Reports
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• v.37 no.2
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• pp.139-143
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• 2004

The antioxidant responsive element (ARE) is a cis-acting regulatory element of genes encoding phase II detoxification enzymes and antioxidant proteins, such as NAD(P)H: quinone oxidoreductase 1, glutathione S-transferases, and glutamate-cysteine ligase. Interestingly, it has been reported that Nrf2 (NF-E2-related factor 2) regulates a wide array of ARE-driven genes in various cell types. Nrf2 is a basic leucine zipper transcription factor, which was originally identified as a binding protein of locus control region of ss-globin gene. The DNA binding sequence of Nrf2 and ARE sequence are very similar, and many studies demonstrated that Nrf2 binds to the ARE sites leading to up-regulation of downstream genes. The function of Nrf2 and its downstream target genes suggests that the Nrf2-ARE pathway is important in the cellular antioxidant defense system. In support of this, many studies showed a critical role of Nrf2 in cellular protection and anti-carcinogenicity, implying that the Nrf2-ARE pathway may serve as a therapeutic target for neurodegenerative diseases and cancers, in which oxidative stress is closely implicated.

• Biomolecules & Therapeutics
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• v.22 no.6
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• pp.553-557
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• 2014

Verapamil is used in the treatment of hypertension, angina pectoris, and atrial fibrillation. Recently, several studies have demonstrated that verapamil increased the optic nerve head blood flow and improved the retrobulbar circulation. All these show that verapamil is potentially useful for ophthalmic treatment. Thus, the aim of this study is to investigate whether verapamil could protect human lens epithelial cell (HLEC) from oxidative stress induced by $H_2O_2$ and the cellular mechanism underlying this protective function. The viability of HLEC was determined by the MTT assay and apoptotic cell death was analyzed by Hoechst 33258 staining. Moreover, Caspase-3 expression was detected by immunocytochemistry and flow cytometry analysis. We also detected Caspase-3 mRNA expression by reverse-transcription-polymerase chain reaction and the GSH content in cell culture. The results showed that oxidative stress produced significant cell apoptotic death and it was reduced by previous treatment with the verapamil. Verapamil was effective in reducing HLEC death mainly through reducing the expression level of apoptosis-related proteins, caspase-3, and increasing glutathione content. Therefore, it was suggested that verapamil was effective in reducing HLEC apoptosis induced by $H_2O_2$.

• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.667-675
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• 2020

Objectives: Exposure to fine dust (PM10) could contribute to the occurrence of cardiovascular disease or respiratory abnormalities. Since garlic is known to possess an anti-oxidative stress effect, the present study was performed to evaluate the effect of garlic intake on fine dust-mediated pulmonary toxicity. Methods: Rats were intratracheally instilled with fine dust at 15 mg/kg body weight (BW)/day for five days following five-day intragastric intubation of garlic at 0.7 or 1.4 g/kgBW/day, or 13.1 mg/kgBW/day S-allyl-cysteine (SAC) as a reference component in garlic. Blood and bronchoalveolar lavage fluid (BALF) were collected. Results: Deposit of fine dust was visually and histopathologically observed in the lungs. Body weight gain during the instillation period was significantly lowered in all the groups instilled with fine dust. Neutrophil numbers in blood were significantly elevated in the fine dust alone group, but this alteration was diminished in the groups administered with garlic. Levels of serum glutathione were lower in the rats instilled with fine dust alone, and this decrease in the glutathione level seems dose-dependently compensated among the groups administered with garlic. Similar findings were observed in the BALF with statistical significance. Typical pulmonary histopathological observation related with inflammation was demonstrated in the lungs of the rats exposed to fine dust alone, whereas such histopathologic findings were not improved in the groups administered with garlic. Conclusion: The present study suggests that garlic intake could alleviate fine dust-mediated pulmonary or systemic toxicities. Further investigation is necessary to delineate the mechanism of garlic-mediated effects on pulmonary function.

• BMB Reports
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• v.37 no.5
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• pp.618-624
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• 2004

All members of R. glutinosa show the unique characteristic of intrinsic tolerance to paraquat (PQ). Antioxidant enzymes have been proposed to be the primary mechanism of PQ resistance in several plant species. Therefore, the antioxidant enzyme systems of R. glutinosa were evaluated by comparatively analyzing cellular antioxidant enzyme levels, and their responses of oxidative stresses and hormones. The levels of ascorbate peroxidase (APX), glutathione reductase (GR), non-specific peroxidase (POX), and superoxide dismutase (SOD) were 7.3-, 4.9-, 2.7- and 1.6-fold higher in PQ-tolerant R. glutinosa than in PQ-susceptible soybeans. However, the activity of catalase (CAT) was about 12-fold higher in the soybeans. The activities of antioxidant enzymes reduced after PQ treatment in the two species, with the exception of POX and SOD in R. glutinosa, which increased by about 40%. Interestingly, the activities of APX, SOD and POX in R. glutinosa, relative to those in soybeans, were further increased by 49, 67 and 93% after PQ treatment. The considerably higher intrinsic levels, and increases in the relative activities of antioxidant enzymes in R. glutinosa under oxidative stress support the possible role of these enzymes in the PQ tolerance of R. glutinosa. However, the relatively lower levels of SOD versus PQ tolerance, and the mixed responses of antioxidant enzymes to stresses and hormones, suggest a possible alternative mechanism(s) for PQ tolerance in R. glutinosa.

• Animal Bioscience
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• v.34 no.8
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• pp.1403-1414
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• 2021

Objective: This study explored the mechanism of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway under conditions of zearalenone (ZEA)-induced oxidative stress in the duodenum of post-weaning gilts. Methods: Forty post-weaning gilts were randomly allocated to four groups and fed diets supplemented with 0, 0.5, 1.0, or 1.5 mg/kg ZEA. Results: The results showed significant reductions in the activity of the antioxidant enzymes total superoxide dismutase and glutathione peroxidase and increases the malondialdehyde content with increasing concentrations of dietary ZEA. Immunohistochemical analysis supported these findings by showing a significantly increased expression of Nrf2 and glutathione peroxidase 1 (GPX1) with increasing concentrations of ZEA. The relative mRNA and protein expression of Nrf2, GPX1 increased linearly (p<0.05) and quadratically (p<0.05), which was consistent with the immunohistochemical results. The relative mRNA expression of Keap1 decreased linearly (p<0.05) and quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet. The relative mRNA expression of modifier subunit of glutamate-cysteine ligase (GCLM) increased quadratically (p<0.05) in all ZEA treatment groups and the relative mRNA expression of quinone oxidoreductase 1 (NQO1) catalytic subunit of glutamate-cysteine ligase decreased linearly (p<0.05) and quadratically (p<0.05) in the ZEA1.0 group and ZEA1.5 group. The relative protein expression of Keap1 and GCLM decreased quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet, respectively. The relative protein expression of NQO1 increased linearly (p<0.05) and quadratically (p<0.05) in all ZEA treatment groups in the duodenum. Conclusion: These findings suggest that ZEA regulates the expression of key factors of the Keap1-Nrf2 signaling pathway in the duodenum, which enables resistance to ZEA-induced oxidative stress. Further studies are needed to examine the effects of ZEA induced oxidative stress on other tissues and organs in post-weaning gilts.

• The Journal of Internal Korean Medicine
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• v.32 no.2
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• pp.288-300
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• 2011

Objectives : The object of this study was to observe the effects of Hwangryungeehwang-tang (HRGHT), which has traditionally been used in Korean medicine for treating diabetes, by administering aqueous extracts to streptozotocin-induced diabetic rats. Methods : Three different dosages of HRGHT extracts were orally administered once a day for 28 days from 3 weeks after streptozotocin treatment (60 mg/kg, single intraperitoneally administered). 6 groups, of 8 rats per group were used in the present study, selected 3 weeks after streptozotocin treatment based on blood glucose levels and body weights. Changes to the body weights, blood glucose levels, serum low density lipoprotein (LDL), high density lipoprotein (HDL), triglyceride and total cholesterol levels were observed, as well as changes on the pancreatic, hepatic and kidney malondialdehyde (MDA) contents for lipid peroxidation and glutathione contents for antioxidant effects. The results were compared with a potent antioxidant silymarin 100 mg/kg, of which the effects on streptozotocin-induced diabetes and related complications are already confirmed. Results : Significant decrease of blood glucose levels, serum LDL, total cholesterol, triglyceride levels, pancreatic, hepatic and renal MDA contents and significant increase of body weights, serum HDL levels, pancreatic, hepatic and renal GSH contents were detected in HRGHT extracts 100 and 200 mg/kg administered groups as compared to the streptozotocin control group. The lowest dosage of HRGHT treated group, 50 mg/kg, did not show any favorable effects as compared with the streptozotocin control. Conclusions : HRGHT has favorable effects on diabetes and related hyperlipidemia. Therefore, more detailed mechanism studies should be conduced in future with efficacy tests of individual herbal compositions of HRGHT and screening of the biological active compounds in the herbs.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.5
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• pp.373-384
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• 2020

Paeonol, quercetin, β-sitosterol, and gallic acid extracted from Moutan Cortex had been reported to possess anti-oxidative, anti-inflammatory, and anti-tumor activities. This work aimed to illustrate the potential anti-oxidative mechanism of monomers in human liver hepatocellular carcinoma (HepG2) cells-induced by hydrogen peroxide (H₂O₂) and to evaluate whether the hepatoprotective effect of monomers was independence or synergy in mice stimulated by carbon tetrachloride (CCl₄). Monomers protected against oxidative stress in HepG2 cells in a dose-response manner by inhibiting the generation of reactive oxygen species, increasing total antioxidant capacity, catalase and superoxide dismutase (SOD) activities, and activating the antioxidative pathway of nuclear factor E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathway. We found that the in vitro antioxidant capacities of paeonol and quercetin were better than those of β-sitosterol and gallic acid. Furthermore, paeonol apparently diminished the levels of alanine transaminase and aspartate aminotransferase, augmented the contents of glutathione and SOD, promoted the expressions of Nrf2 and heme oxygenase-1 proteins in mice stimulated by CCl₄. In HepG2 cells, paeonol, quercetin, β-sitosterol, and gallic acid play a defensive role against H₂O₂-induced oxidative stress through activating Nrf2/Keap1 pathway, indicating that these monomers have anti-oxidative properties. Totally, paeonol and quercetin exerted anti-oxidative and hepatoprotective effects, which is independent rather than synergy.

• BMB Reports
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• v.32 no.3
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• pp.232-238
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• 1999

Sex differences in the induction of microsomal cytochrome P-450 (CYP) and the activities of several related enzymes of Sprague-Dawley rats treated with 1-bromopropane (1-BrP) were investigated. Male and female rats were exposed to 50, 300, and 1800 ppm of 1-BrP per kg body weight (6 h a day,S days a week, 8 weeks) by inhalation. The mean body weight of 1-BrP treated groups increased according to the day elapsed, but four and five weeks respectively after the start of the exposure, the mean body weight of male and female rats had significantly reduced in the group treated with 1800 ppm 1-BrP compared with the control group (p<0.01). While the relative weights of liver increased in both sexes, statistical significance in both sexes was found only in the group receiving 1800 ppm/kg of 1-BrP (p<0.01). The total contents of CYP, $b_5$, NADPH-P-450 reductase, NADH $b_5$ reductase, ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-dealkylase (PROD), and p-nitrophenol hydroxylase (pNPH) activities were examined for the possible effects of 1-BrP. No significant changes in the CYP and $b_5$ contents, NADPH-P-450 reuctase, NADH $b_5$ reductase, ethoxyresorufin-O-deethylase (EROD), and pentoxyresorufin- O-dealkylase (PROD) were observed between the control and treated groups. The activity of pNPH increased steadily with the increase in the concentration of 1-BrP in both sexes, but was significantly increased only in the 1800 ppm-treated group of male rats (p<0.05). When Western blottings were carried out with three monoclonal antibodies (MAb 1-7-1, MAb 2-66-3, and MAb 1-98-1) which were specific against CYP1A1/2, CYP2B1/2, and CYP2E1, respectively, a strong signal corresponding to CYP2E1 was observed in microsomes obtained from rats treated with 1-BrP. Glutathione S-transferase (GST) activity and the content of lipid peroxide significantly increased in the treated groups compared with the control group (p<0.05). These results suggest that 1-BrP can primarily induce CYP2E1 as the major form and that GST phase II enzymes play important roles in 1-BrP metabolism, showing sex-dependence in the metabolic mechanism of 1-BrP in the rat liver.

• BMB Reports
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• v.39 no.2
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• pp.197-207
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• 2006

Cajanus indicus is a herb with medicinal properties and is traditionally used to treat various forms of liver disorders. Present study aimed to evaluate the effect of a 43 kD protein isolated from the leaves of this herb against chloroform induced hepatotoxicity. Male albino mice were intraperitoneally treated with 2mg/kg body weight of the protein for 5 days followed by oral application of chloroform (0.75ml/kg body weight) for 2 days. Different biochemical parameters related to physiology and pathophysiology of liver, such as, serum glutamate pyruvate transaminase and alkaline phosphatase were determined in the murine sera under various experimental conditions. Direct antioxidant role of the protein was also determined from its reaction with Diphenyl picryl hydraxyl radical, superoxide radical and hydrogen peroxide. To find out the mode of action of this protein against chloroform induced liver damage, levels of antioxidant enzymes catalase, superoxide dismutase and glutathione-S-transferase were measured from liver homogenates. Peroxidation of membrane lipids both in vivo and in vitro were also measured as malonaldialdehyde. Finally, histopathological analyses were done from liver sections of control, toxin treated and protein pre- and post-treated (along with the toxin) mice. Levels of serum glutamate pyruvate transaminase and alkaline phosphatase, which showed an elevation in chloroform induced hepatic damage, were brought down near to the normal levels with the protein pretreatment. On the contrary, the levels of anti-oxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferase that had gone down in mice orally fed with chloroform were significantly elevated in protein pretreated ones. Besides, chloroform induced lipid peroxidation was effectively reduced by protein treatment both in vivo and in vitro. In cell free system the protein effectively quenched diphenyl picryl hydrazyl radical and superoxide radical, though it could not catalyse the breakdown of hydrogen peroxide. Post treatment with the protein for 3 days after 2 days of chloroform administration showed similar results. Histopathological studies indicated that chloroform induced extensive tissue damage was less severe in the mice livers treated with the 43 kD protein prior and post to the toxin administration. Results from all these data suggest that the protein possesses both preventive and curative role against chloroform induced hepatotoxicity and probably acts by an anti-oxidative defense mechanism.

• Journal of Life Science
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• v.17 no.12
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• pp.1649-1653
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• 2007

High temperature stresses have caused growth inhibition and delayed heading in highland cultivation Chinese cabbage during summer in Korea. We have studied high temperature stress responses in the terms of changes of inorganic components and proteins by proteomic analyses. Insufficiencies of nitrogen and phosphorus have affected growth rate and calcium deficiency has caused blunted heading. Proteins extracted from Brassica seedling grown at the altitude of 600m and 900m in the Mount Jilun were extracted and analysed by 2-dimentional polyacrylamide gel electrophoresis. Profiles of protein expression was then analyzed by 2-dimentional gel analyses. Protein spots showing different expression level were picked using the spot handling workstation and subjected to MALDI-TOF MS. Total 48 protein spots were analyzed by MALDI-TOF MS and 30 proteins spots out of 48 were identified by peptide mass fingerprinting analyses. Fourteen proteins were up-regulated in extracts from the altitude of 900m and they were identified as oxygen-evolving proteins, rubisco activase and ATPase etc. Sixteen proteins were up-regulated in extracts from the altitude of 600m and they were identified as glutathione S-transferase(1, 28kD cold induced- and 24 kD auxin-binding proteins) and salt-stress induced protein etc. These stress-induced proteins were related to the mediated protective mechanism against oxidative damage during various stresses. The results indicated that physiological phenomenon in response to high temperature stresses might be resulted by complex and multiple array of responses with drought, heat, oxidative, salt, and cold by high temperature.