• BMB Reports
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• v.32 no.5
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• pp.451-455
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• 1999

The concentrations of L-ascorbic acid (AsA, ascorbate, vitamin C) and its biosynthetic and metabolically-related enzymes such as L-galactono-1,4-lactone dehydrogenase (GLDase), ascorbate peroxidase (APX), and ascorbate oxidase (ASO) were investigated in suspension cultures of Scutellaria baicalensis. Cells growing from 4 days after subculture (DAS) to 9 DAS and from 16 DAS to 19 DAS showed a diauxic growth, and then growth rapidly decreased with further culturing. The AsA content slowly increased to 19 DAS, reached a maximum at 21 DAS (ca $120\;{\mu}g/g$ dry cell wt), and then rapidly decreased with further culturing. GLDase and ASO activity were well correlated with the cell growth curve, showing a maximum at 19 DAS, whereas APX activity showed a good correlation with the changes in AsA content, showing a maximum at 21 DAS. The total ascorbate contents (reduced form, AsA, and oxidized form, dehydroascorbate, DHA) were markedly enhanced at 10 DAS when L-galactose and L-galactono-1,4-lactone (25 mM) were added to SH medium supplemented with 20 g/l sucrose at 9 DAS, by 5.5 and 6.8 times, respectively. DHA composed more than 90% of the total ascorbate contents in suspension cultures of S. baicalensis, even though the ratio of reduced to oxidized form slightly varied with cell growth stage. The results indicate that L-galactose and L-galactono-1,4-lactone are effective precursors of AsA in cell cultures of S. baicalensis, and that in vitro cultured cells provide suitable biomaterials for the study of biosynthesis and metabolism of AsA.

• Journal of Life Science
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• v.20 no.8
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• pp.1173-1180
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• 2010

We investigated changes in photosynthesis and activity of ascorbate peroxidase (APX) that scavenges ROS as responses to oxidative stress induced by salinity in rice (Oryza sativa L.). Photosynthetic efficiency of rice leaves, monitored in terms of Fv/Fm, declined with the increase of salt concentration (100-300 mM NaCl). Salinity caused an increase of $H_2O_2$ in leaves of rice, with an increase of APX activity. Among total APX isoforms, an isoform of stromal-APX 1 in leaves of rice was completely inactivated by 300 mM NaCl, but was not affected by chilling or drought. The results suggest that salt stress acts in quite a different mechanism in relation to the activity of stromal-APX from that of other stresses such chilling and drought. We carried out RT-PCR for analysis of genes expression of APX isoforms as affected by salt stress. The expression of cytosolic APX/thylakoid-bound APX genes in leaves of rice exposed to salt stress was increased, while stromal APX gene expression rapidly declined.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.147-155
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• 1999

Antioxidant effects of serotonin and L-DOPA on neuronal tissues were examined by studying the oxidative damages of brain synaptosomal components. The study further explored the mechanism by which they exert protective actions. Serotonin and L-DOPA (1 ${\mu}M$ to 1 mM) significantly inhibited lipid peroxidation of brain tissues by either $Fe^{2+}$ and ascorbate or t-butyl hydroperoxide in a dose dependent fashion. Protective effect of serotonin on the peroxidative actions of both systems was greater than that of L-DOPA. Protein oxidation of synaptosomes caused by $Fe^{2+}$ and ascorbate was attenuated by serotonin and L-DOPA. Protein oxidation more sensitively responded to L-DOPA rather than serotonin. Serotonin and L-DOPA (100 ${\mu}M$) decreased effectively the oxidation of synaptosomal sulfhydryl groups caused by $Fe^{2+}$ and ascorbate. The production of hydroxyl radical caused by either $Fe^{3+},$ EDTA, H_2O_2$ and ascorbate or xanthine and xanthine oxidase was significantly decreased by serotonin and L-DOPA (1 mM). Equal concentrations of serotonin and L-DOPA restored synaptosomal $Ca^{2+}$ uptake decreased by $Fe^{2+}$ and ascorbate, which is responsible for SOD and catalase. Protective effects of serotonin and L-DOPA on brain synaptosomes may be attributed to their removing action on reactive oxidants, hydroxyl radicals and probably iron-oxygen complex, without chelating action on iron.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.81-81
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• 2019

Ginseng seeds are one of short-lived seeds species which loose their viability easily in the condition of conventional storage. Cryopreservation using liquid nitrogen (LN) has been recommended as a alternative storage for this kind of germplasm short lived or dessiccation-sensitive. This study was performed to find out whether cryopreservation could affect physiological change such as enzyme activity induced by reactive oxygen species. In this work, the redox ratio of ascorbate and glutathione were examined onto ginseng seedlings before and after LN storage of seeds for 1 day using spectrophotometer method. Reduced ascorbate (ASA) was increased while oxidized ascorbate (DHA) was decreased slightly for both after 1d-LN storage. And for glutathione also, reduced form (GSH) was increased while oxidized form (GSSG) was decreased slightly for both after 1d-LN storage. Consequently total phenol compound and ion leakage after LN storage showed no significant differences. Additionally root growth from the seeds after LN storage was not affected by ultra low temperature. From the above results, we may suggest that cryopreservation could be recommended for storage tool of ginseng seeds even with low viability also and expected to make slower seed aging process during preservation period through further study.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.510-518
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• 2003

Protective effects of natural components including genistein (4',5,7-trihydroxyisoflavone) from Glycine max MERRILL on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. Genistein $(10{\sim}100\;{\mu}m)$ suppressed photohemolysis in a concentration-dependent manner, and was more effective than the lipid peroxidation chain blocker, ${\alpha}$-tocopherol (Vit. E). Glycoside of genistein, genistin, the water-soluble antioxidant, L-ascorbate, and the iron chelator, myo-inositol hexaphosphoric acid dodecasodium salt (sodium phytate) did not exhibit protective effect against photohemolysis. L-Ascorbate and sodium phytate stimulated photohemolysis at high concentration $(500\;{\mu}m)$. ${\alpha}$-Carotene 3,3'-diol (lutein), a singlet oxygen $(^1O_2)$ quencher, exhibited pronounced protective effect, an indication that $^1O_2$ is important in photohemolysis sensitized by rose-bengal. Reactive oxygen scavenging activities $(OSC_{50})$ of natural antioxidants including genistein on reactive oxygen species (ROS) generated in $Fe^{3+}-EDTA/H_2O_2$ system using the luminol-dependent chemiluminescence assay were in the order of sodium phytate > L-ascorbate > ${\alpha}$-tocopherol > genistein > genistin. $OSC_{50}$ value of genistein, genistin, ${\alpha}$-tocopherol, L-ascorbate, and sodium phytate were 41.0, 109.0, 9.0, 5.2, and $0.56{\mu}m$ respectively. The order of free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity $(FSC_{50})$ was L-ascorbate > ${\alpha}$-tocopherol > genistein > genistin. These results indicate that genistein can function as an antioxidant in biological systems, particularly skin exposed to solar UV radiation by scavenging $^1O_2$ and other ROS, and to protect cellular membranes against ROS.

• Analytical Science and Technology
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• v.7 no.2
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• pp.149-153
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• 1994

An amperometric sensor for L-ascorbic acid(AA) in methanol media has been made by immobilizing squash-tissues on a graphite rod disk. A detection limit of the electrode was $2{\times}10^{-6}M$ L-ascorbic acid. In comparison with an isolated enzyme based ascorbate oxidase(AO) electrode, the plant-tissue electrode offered high biocatalytic stability and activity and extremely low cost. The electrode has a useful lifetime of 1 week.

• BMB Reports
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• v.36 no.4
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• pp.403-408
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• 2003

The relative activities of neutral, cationic, and anionic chromium ascorbate complexes toward isolated human mitochondrial and genomic DNA were investigated at physiologically relevant conditions by agarose gel electrophoresis. A direct relationship between the charge of the Cr(III) species and their DNA-damaging properties was found. The cationic species were found to be fully capable of DNA-cleavage, even in short incubation periods. Incubations were also performed in the presence of amino acids. No apparent effect was observed under the applied experimental conditions to facilitate or prevent damage through the ternary amino acid-Cr-DNA adduct formation or binary chromium-amino acid complex formation.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.165.1-165
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• 2003

복숭아는 절단 후 표면의 갈변현상이나 당도 저하 등이 발생하여 신선편이 식품화시 품질열화의 원인이 된다. 이에 본 실험에서는 일차적으로 유명 품종에 한해 fresh-cut peach의 anti-browning chemicals를 탐색하고, 그 결과를 통해 이차적으로 효과가 우수한 chemicals를 선정하여 백향 품종에 농도별 실험을 행하였다. 유명 품종을 반으로 절단한 후 제핵하고 8등분하여 1% ascorbic acid, 1% sodium chloride, 1% sodium ascorbate monohydrate, 0.005% 4-hexylresorcinol 용액에 3분간 침지시켜 draining한 후, PP tray에 담고 PP film으로 밀봉하여 4$^{\circ}C$에서 저장하였다. 가용성고형분은 to sodium chloride 용액으로 처리한 구에서 가장 높게 유지되었고 pH 또한 비교적 일정하였으며, 1% sodium chloride과 1% sodium ascorbate monohydrate 용액으로 처리한 구의 L값이 높게 유지되었다. 따라서 fresh-cut peach에 효과가 있는 것으로 판단되는 이 두 chemicals의 농도별 용액을 조제하여 같은 방법으로 백향 품종의 갈변저해제로서 처리하였다. 그 결과 2% sodium chloride의 가용성고형분이 가장 높게 유지되었으며 2% sodium ascorbate monohydrate 다음으로 2% sodium chloride 용액 처리구의 L값의 변화 양상이 가장 양호한 것으로 나타났다. 따라서 종합적으로 살펴볼 때, 2% sodium chloride 용액의 처리가 fresh-cut peach의 품질 변화 억제에 적합하다고 판단되었다.

• BMB Reports
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• v.29 no.6
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• pp.564-568
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• 1996

Bursts of ethylene production occurred in twice at an early exponential (EEP) and prestationary (PSP) phases, respectively, during growth of callus tissue isolated from the root of soybean seedlings. The second burst of ethylene production at PSP was smaller in magnitude than the earlier one at EEP, but was followed by increases in both guaiacol peroxidase (GuPOX) and ascorbate peroxidase (AsPOX). The increase in AsPOX activity was also preceded by an increase in lipoxygenase (LOX) activity. Treatment of the tissue with the ethylene antagonist 2,5-norbonadiene (NBD) resulted in substantial reduction in LOX and AsPOX activities during this period. GuPOX activity was reduced only slightly, if any, by NBD. Role of ethylene in the sequential induction of LOX and AsPOX in senescing callus tissue is discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1450-1458
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• 2005

Quality characteristics of mul-kimchi prepared using eastern deep seawater added with $0.1\%$ chitosan-ascorbate (CA) were investigated during fermentation for 12 days at $10^{\circ}C$, in an effort to effectively utilize the eastern deep seawater in Korea. Four water sources were considered for preparation of mul-kimchi; (1)distilled water added with $1\%$ mineral salt (DW), (2) eastern deep seawater (containing $6\%$ salt) diluted to $1\%$ salt concentration with distilled water (ED), (3) DW+CA (DW-CA), and (4) ED+CA (ED-CA). Juice of mul-kimchi prepared with ED-CA as a water source showed higher PH and antioxidant activity, and lower acidity, total microbe numbers, turbidity and alcohol insoluble substance compared with those Prepared with other three water sources. The former also showed higher overall acceptability compared with the latter. This study demonstrated the possibility of use of eastern deep seawater added with chitosan-ascorbate as a water source for extension of shelf-life of mul-kimchi.