• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.509-514
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• 2002

A method to determin Fe(II) and Fe(III) ion in aqueous solution by chemiluminescence method using a stopped flow system has been studied. The method is based on the increased chemiluminescence intensity with the addition of Fe(III) ion to a solution of lucigenin and hydrogen peroxide. The effects of KOH concentration, flow rate of reagents, $H_2O_2$ concentration and citric acid concentration used for the masking of Fe(II) ion on the chemilu-minescence intensity have been investigated. The calibration curve for total Fe was linear over the range from 1.0${\times}$$10^{-6}$ M to 1.0${\times}$$10^{-4}$M, coefficient of correlation was 0.996 and the detection limit was 1.0${\times}$$10^{-7}$M under the optimal exper-imental conditions of 4.0 M, 2.0 M, 3.5 mL/min for the concentration of $H_2O_2,$ KOH and flow rate of reagents, respec-tively. The calibration curve for Fe(Ⅲ) was linear over the range from 1.0${\times}$$10^{-6}$M to 1.0${\times}10^{-4}$ M, the coefficient of correlation was 0.997 and the detection limit was 5.0${\times}$$10^{-7}$M under the optimal experimental conditions.

• BMB Reports
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• v.49 no.11
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• pp.617-622
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• 2016

Oxidative stress is closely associated with various diseases and is considered to be a major factor in ischemia. NAD(P)H: quinone oxidoreductase 1 (NQO1) protein is a known antioxidant protein that plays a protective role in various cells against oxidative stress. We therefore investigated the effects of cell permeable Tat-NQO1 protein on hippocampal HT-22 cells, and in an animal ischemia model. The Tat-NQO1 protein transduced into HT-22 cells, and significantly inhibited against hydrogen peroxide ($H_2O_2$)-induced cell death and cellular toxicities. Tat-NQO1 protein inhibited the Akt and mitogen activated protein kinases (MAPK) activation as well as caspase-3 expression levels, in $H_2O_2$ exposed HT-22 cells. Moreover, Tat-NQO1 protein transduced into the CA1 region of the hippocampus of the animal brain and drastically protected against ischemic injury. Our results indicate that Tat-NQO1 protein exerts protection against neuronal cell death induced by oxidative stress, suggesting that Tat-NQO1 protein may potentially provide a therapeutic agent for neuronal diseases.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.258-264
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• 2011

Glutathione (GSH) has important roles in cellular defense against oxidative stress, 1) direct scavenging of reactive oxygen species (ROS), and 2) coenzyme of ROS scavenging enzyme like glutathione peroxidases (GPx). GSH peroxidase reduces free hydrogen peroxide to water using 2GSH. $N$-acetyl-L-cysteine (NAC), one of the antioxidants, is used as a precursor for intracellular GSH. In this study, relation of GSH, NAC, and GSH peroxidase was investigated through transcriptional expression of $GPX1$ and $GPX2$, which are GSH peroxidase encoding genes, in yeast cells treated with 0 mM to 20 mM of NAC or in combination with 100 Gy gamma-rays. The transcriptional expression of $GPX1$ and $GPX2$ was induced by NAC and 100 Gy gamma-rays. The gene expression of both GSH peroxidases was decreased with increasing concentrations of NAC in irradiated yeast cells. These results suggest that elevation of intracellular GSH by NAC and oxidative stress and ROS generated from gamma-rays induces expression of GSH peroxidase genes, and that NAC can protect the yeast cells against ROS generated from gamma-rays through direct scavenging of ROS and transcriptional activation of GSH peroxidase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.133-138
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• 2006

To differentiate barley responses to drought and salt stress, barley seedlings at the second leaf stage were treated with 218 mM NaCl and 29.5% PEG6000 iso-osmotic to 218 mM NaCl for 6 days. Shoot fresh weight and leaf relative water content of barley seedlings were more reduced by drought compared to salt stress. Hydrogen peroxide content increased under both stress conditions, but its accumulation was more severe at 6 days after salt stress. The activity of ascorbate peroxidase, glutathione reductase (GR) and catalase (CAT) was enhanced until 4 days after salt stress. On the other hand, the activity of GR and CAT increased gradually until 6 days after drought. Among the amino acids measured in this study, the accumulation of glycine, arginine and GABA (${\gamma}-aminobutyric$ acid) was lower under salt stress than drought. However, considerably larger amount of proline was accumulated by salt stress. It is concluded that the antioxidant enzymes activity and amino acid content of barley seed-lings were differently regulated in response to the isoosmotic condition of salt and drought stress.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.222-227
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• 2017

Red ginseng prepared from fresh 6-year-old ginseng treated with colloidal gold nanoparticles was extracted using hot water to evaluate its total phenolic and flavonoid contents, antioxidant capacity, and neuroprotective effects. Water extract of red ginseng treated with gold nanoparticles (WERGGN) had total phenolic and total flavonoid contents of 212.2 mg gallic acid equivalents/$^{\circ}Bx$ and 3.5 mg catechin equivalents/$^{\circ}Bx$, respectively. The antioxidant capacities of WERGGN measured using ABTS, DPPH, and ORAC assays were 272.3, 141.2, and 868.4 mg vitamin C equivalents/$^{\circ}Bx$, respectively. The WERGGN showed protective effects on the viability of neuron-like PC-12 cells against oxidative stress induced by hydrogen peroxide in a dose-dependent manner, partly because of a reduction in intracellular oxidative stress. Acetylcholinesterase and butyrylcholinesterase, which degrade the neurotransmitter acetylcholine to terminate neurotransmission, were inhibited by treatment with WERGGN. These results suggest that WERGGN is useful as a functional material to decrease oxidative stress and neuronal damage.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.546-554
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• 2020

Natural food additives have recently attracted attention as alternatives to synthetic additives. However, little information is available regarding their potential toxicity. In this study, we evaluated ten different natural food additives that are widely used in commercial foods in South Korea based on their actual usage level and daily intake. The results showed that none of the tested natural additives exhibited cytotoxicity in terms of inhibition of cell proliferation/viability and lactate dehydrogenase leakage. Additionally, the tested natural food additives did not generate intracellular reactive oxygen species (ROS), whereas they significantly decreased intracellular ROS levels produced by hydrogen peroxide. Moreover, none of the tested natural additives affected cell proliferation and viability in 2D and 3D intestinal epithelium models. Taken together, the ten natural food additives did not exhibit cytotoxicity in their actual usage levels. These findings can be used to further assess the toxicity of natural food additives.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.564-577
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• 2016

Salinity stress limits plant cultivation in many areas worldwide; however, persimmon (Diospyros spp.) has high tolerance to salt. Five accessions of Diospyros [three of Diospyros lotus (accession numbers 824, 846, and 847); one of Diospyros kaki var. sylvestris (869); and one of Diospyros virginiana (844)] were chosen for analysis of salinity stress. We compared the effects of salt stress on plant growth, relative water content (RWC), malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide content ($H_2O_2$), and antioxidative enzyme activities (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD; and ascorbate peroxidase, APX) in leaves of healthy potted seedlings from each of the five accessions after salt treatment for 25 days. Salt stress affected the growth of plants in all five accessions, with all three D. lotus accessions showing the most severe effect. Salt stress increased membrane lipid peroxidation in all accessions, but a stronger increase was observed in the three D. lotus accessions. Moreover, accumulation of $H_2O_2$ was faster in salt-sensitive D. lotus compared to salt-tolerant D. virginiana 844. The activities of all antioxidant enzymes increased in D. virginiana 844 and in D. kaki var. sylvestris 869; the activities of SOD, CAT, and APX were at similar levels in D. virginiana 844 and D. kaki var. sylvestris 869, but POD activity was stimulated to a greater extent in D. virginiana 844. The activities of all antioxidant enzymes (except POD) decreased in D. lotus 824 and increased (except for SOD) in D.lotus 846. The activities of SOD and APX decreased in D. lotus 847, whereas POD and CAT activities both increased. Relative water content decreased significantly in D. lotus. No significant changes in lipid peroxidation or relevant antioxidant parameters were detected in any of the accessions in controls treated with 0.0% NaCl. D. virginiana 844 had higher antioxidant capacity in response to salinity compared to other persimmon rootstocks. These results indicate that changes of these key physiological variables are related to salinity resistance in different accessions of persimmon.

• Journal of Life Science
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• v.19 no.2
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• pp.228-233
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• 2009

The purpose of this study is to evaluate the activities of five different antioxidant enzymes in various tissues of Papilio xuthus during pupal stage. Superoxide dismutase (SOD) activity in haemolymph was the highest just after pupation and then decreased gradually until 7 days after pupation but the activity in other tissue was constant during metamorphosis. This result indicates that primary antioxidant process of reactive oxygen species proceed in haemolymph. Catalase (CAT) activity in studied tissues was also the highest just after pupation and its relative activity was also high during pupal stage, suggesting that CAT is the primary enzyme in catalysis of hydrogen peroxide. Glutathion peroxidase (GPX) activity was constant and its relative activity was very low in all tested tissues. Glutathione S-transferase (GST) activity in haemolymph was high at 3 days and 5 days after pupation, and the activity in fat body was the highest at the 1 day after pupation and then decreased gradually for 7 days after pupation. Glutathion reductase (GR) activity in haemolymph and fat body was high at 1 day after pupation, but relatively low GR activity was detected in the rest tissues. Based on these results, GST activity was higher than that of GPX and GR, and it is also believed that GST was more involved in reduction process through lipid peroxidation than GPX.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.289-298
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• 2015

Edaravone (Eda) is a potent scavenger of inhibiting free radicals including hydroxyl radicals ($H_2O_2$). Reactive oxygen species (ROS) such as $H_2O_2$ can alter most kinds of cellular molecules such as lipids, proteins and nucleic acids, cellular apoptosis. In addition, oxidative stress from over-production of ROS is involved in the defective embryo development of porcine. Previous study reported that Eda has protective effects against oxidative stress-like cellular damage. However, the effect of Eda on the preimplantation porcine embryos development under oxidative stress is unclear. Therefore, in this study, the effects of Eda on blastocyst development, expression levels of ROS, and apoptotic index were first investigated in preimplantation porcine embryos. After in vitro fertilization, porcine embryos were cultured for 6 days in PZM medium with Eda ($10{\mu}M$), $H_2O_2$ ($200{\mu}M$), and Eda+$H_2O_2$ treated group, respectively. Rate of blastocyst development was significantly increased (P<0.05) in the Eda treated group compared with only $H_2O_2$ treated group. And, we measured intracellular levels of ROS by DCF-DA staining methods and investigated numbers of apoptotic nuclei by TUNEL assay analysis is in porcine blastocyst, respectively. Both intracellular ROS levels and the numbers of apoptotic nucleic were significantly decreased (P<0.05) in porcine blastocysts cultured with Eda ($10{\mu}M$). More over, the total cell number of blastocysts were significantly increased (P<0.05) in the Eda-treated group compared with untreated group and the only $H_2O_2$ treated group. Based on the results, Eda was related to regulate as antioxidant-like function according to the reducing ROS levels during preimplantation periods. Also, Eda is beneficial for developmental competence and preimplantation quality of porcine embryos. Therefore, we concluded that Eda has protective effect to ROS derived apoptotic stress in preimplantation porcine embryos.

• Journal of fish pathology
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• v.10 no.1
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• pp.21-29
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• 1997

We investigated on the prevalence and extermination of scuticociliatids parasitic on cultured japanese flounder, Paralichthys olivaceus in land-marine tank system of southern Korea from January to February in 1997. The gills and the skin showed the highest infection rate(60%), and the brain showed the lowest(22%). Also, fish secreted large quantity of mucus with a bleeding and ulcerated lesions on the infected sites. The number of the parasites in inflowing sea water, surface water and bottom water of farming tank ranged 0~1 individuals/$100m\ell$, 0~413 individuals/$100m\ell$ and $7\sim7.3{\times}10^4$ individuals/$100m\ell$, respectively. This parasite was died within 2 hours in 50~500 ppm, 48 hours of 10 ppm formalin or hydrogen peroxide, 1 hour in 50~500 ppm, 80 minutes of 10 ppm oligo chitosan and 10 minute in 100% but did not died until 48 hours in 10~70% fresh water.