• Applied Biological Chemistry
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• v.35 no.3
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• pp.170-172
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• 1992

Four types of polyphenol oxidase were isolated from the crude extract of a Ligularia fischeri by gel filtration on Sephadex G-150. Optimum pH and temperature for the activity of partially purified enzyme were 7.5 and $25^{\circ}C$, respectively. It was stable at temperature $40^{\circ}C$ when examined at pH 7.5 for 5 min, and lost 90% of its activity at $70^{\circ}C$ in 30 min at pH 7.5. The enzyme has good activity on catechol and chlorogenic acid but was inactive on dopamine.

• Analytical Science and Technology
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• v.15 no.5
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• pp.445-450
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• 2002

A sensitive gas chromatographic method has been established for the determination of total iodide in seawater as their volatile organic derivative. The method is based on the formation of 4-iodo-2,6-dimethylphenol with 2,6-dimethylphenol in matrix and a single-step extraction of the derivative with ethyl ether, which are then measured by gas chromatography-mass spectrometry (selected ion monitoring). Iodate in sea water was completely reduced to iodide with ascorbic acid and acetic acid. The detection limit was 0.1 ng/mL in seawater and the calibration curve showed good linearity with r=0.9997. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of total iodide in seawater. Total iodide in sea water was found about 30 ng/ml.

• Analytical Science and Technology
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• v.11 no.2
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• pp.96-104
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• 1998

A photodiode array multichannel detector system for capillary electrophoresis was developed. The photodiode array detector for capillary electrophoresis (CE-PDA) has 1024 photodetectors and can analyze sample by measuring UV/VIS absorption spectrum in 275~675 nm wavelength range. The CE-PDA instrument can get a spectrum in 30 ms during sample separation and can be programmed by a PC to control various experimental conditions required for sample analysis. The performance of the multichannel CE-PDA instrument was tested using L-ascorbic acid and alizarin yellow GG mixture. The reproducibility test of the CE-PDA system showed 5.6% RSD.

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.43-46
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• 1999

Taurine is known to suppress oxidant-induced tissue injury by stabilizing biomembrane and scavanging free radicals. The purpose of this study was to determne the antioxidative and antimutabenic acitvities of taurine, ad to compare those acitivities with major antioxidants. For the measurement of antioxidative capacity, 0.05 , 0.1,0.5 and 1.0mg/ml of taurine, L-Ascorbic acid, alpha-tocopherol, and BHT (dibuty hydroxiy toluene)were prepared and tested for their ability to donate electrons to DPPH (1,1-diphenyl-2-picryl-hydrazyl). Antimutagenic acitivity was examined using the Ames salmonela test system at concentrations of 600, 900 and 1200ug/ml. Results indicated that taurine possesses electron-donating capacity, however, the degree of donation was very weak compared to the major antioxidants tested. However, taurine was evaluated as a potent mutation suppressor. Antimutagenic capacity was in increasing order BHT>taurine>L-ascorbic acid>alpha-tocopherol at concentrations of 600 and 900ug/ml. There was a dose-dependent increase in antimutabenicity of these compounds , however, antimutagenity of the 900ug taurie/plate was not significantly differently from that of 1200ug taurine/plate. These results indicate that taurine effectively suppresses the mutagenicity of AFB1 without noticeable elelctron donating ability.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.526-529
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• 1993

The present study was conducted to investigate nitrite-scavenging ability of the components of Cassiae torae semen, Cassia tora L. The nitrite-scavenging effects of fractions obtained from methanol extract of Cassiae torae semen, Cassia tora L. were strong in ethyl acetate fraction, chloroform fraction, water soluble fraction and ethyl ether fraction in order. Compound D showed the strongest nitrite-scavenging effects among compound A, B, C, D separated from Cassiae torae semen. Compound D separated from Cassiae torae semen possessed ten-fold stronger the nitrite-scavenging effect than ascorbic acid.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.145-146
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• 2001

There are increasing evidences that L-ascorbic acid (LAA) is selectively toxic to some types of tumors at physiological concentrations as a prooxidant, rather than antioxidant. However, the mechanism by which LAA initiates cellular signaling toward cell death is still unclear. Therefore, to determine whether LAA might be useful for the treatment of human acute promyelocytic leukemia (APL), HL-60 cells, the effects of LAA on proliferation, redox system, MAPK and induction of apoptotic cascades were investigated.(omitted)

• Food Science and Preservation
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• v.6 no.3
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• pp.276-280
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• 1999

To maintain the quality characteristics of vegetables, produce was dipped in Korean medical herb extracts (KMHE) such as Rheum palmatum L. or Coptis chinensis Franch with different concentration. Dipping in 500 ppm KMHE solution was suitable for the reduction or microbial load on cucumber, and 100 ppm KMHE solution was appropriate for others. Dipping time was suitable for produce about 10 minutes, and the temperature of dining solution had a limited effect cm the microbial load reduction. Antimicrobial activity of Coptis chinensis Franch and Rheum palmatum L. was maintained for cucumber and zucchini wrapped with polyvinylchloride film during storage at 10$^{\circ}C$.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.224-229
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• 2013

Bromotopsentin (BSM) is a bisindole alkaloid compound, which is recognized as a metabolite of the marine sponge Spongosorites sp. In this study, the antioxidant activity of BSM was investigated. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, the trolox equivalent antioxidant capacity (TEAC) assay, the superoxide radical scavenging (NBT) assay, the lipid peroxidation and hydroxyl radical-induced DNA damage assays were carried out to evaluate the antioxidant activity of BSM. It was found that BSM had stronger scavenging activity on the stable free radical DPPH and superoxide radical than L-ascorbic acid with an $IC_{50}$ value of 62 and 64 ${\mu}M$, respectively. The TEAC value which indicated the total antioxidant capacity of BSM was about 0.8, which was also stronger than L-ascorbic acid. About 1.3 ${\mu}M$ of BSM induced 50% inhibition of lipid peroxidation. 60 nM of BSM exhibited a significant protective activity against DNA strand scission by hydroxyl radical on pBR322 DNA. Taken together, we suggest that BSM possesses strong antioxidant activity, and could be a valuable new addition to the list of anti-aging chemotherapeutic agents.

• Korean journal of food and cookery science
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• v.26 no.4
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• pp.422-427
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• 2010

This study was conducted to investigate the antioxidant effect and properties of unfermented tea and fermented tea made with Rhodotorula yeast. The levels of crude fat and crude protein in the fermented tea were higher than those in the unfermented tea. The water-soluble phenol levels of unfermented tea and fermented tea were 912.5 and 2,445.24 ppm, respectively. The total amino acid content of fermented tea was greater than that of unfermented tea;,- the amino acid concentrations of alanine, valine, leucine, and lysine were 25.58, 24.38, 27.96, and 14.14 ${\mu}g/mL$, respectively. The DPPH radical scavenging activities of the unfermented and fermented teas were 32.14 and 41.57%, respectively; this is in contrast to 29.73% for L-ascorbic acid(150 ppm). The reducing power activity of fermented tea was 41.57%, and that of unfermented tea was 32.14%.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.137-142
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• 1994

Myrosinase in leaf mustard was purified and characterized to furnish a grounding information for utilizing the pungent taste and the potential antimicrobial capability of Dolsan leaf mustard to enhance the taste and storage life of kimchi. When myrosinase was purified from leaf mustard through a series of DEAE Sephadex, chromatofocusing and Con A Sepharose column chromatography, specific activity of the enzyme increased 7107-fold compared with that of crude enzyme preparation, and 18.8% yield was obtained. The purified myrosinase showed the optimum pH of 5.9, isoelectric point of 4.6, molecular weight of 129 kD, Km of 0.206 mM, and Vmax of $2.039\;{\mu}M{\cdot}min^{-1}{\cdot}mg\;protein^{-1}$, respectively. The optimum concentration of L-ascorbic for the maximum activity of the enzyme was 0.6 mM, and the enzyme activity decreased at a higher concentration of L-ascorbic acid than 0.6 mM, showing almost no enzyme activity at a L-ascorbic acid concentration of higher than 2.0 mM. Myrosinase activity in leaf mustard kimchi immediately after the kimchi was formulated was shown to be about 70 nmol/min/mg protein which decreased rapidly after 3 days of storage at $20^{\circ}C$, showing that less than half and almost none of the enzyme activity was retained in 4 and 10 days of storage, respectively.