• Food Science and Preservation
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• v.11 no.4
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• pp.544-549
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• 2004

Major components and antioxidant activity of fermented tea were investigated. Contents of total flavonoid and total phenol showed the highest score in ethanol extract ($481.4\;{\mu}g/g$ and 33.5 g/100g), respectively. Their contents in hot water extract ($405.7\;{\mu}g/g$ and 23.6 g/100g) were lower than those of the others extracts. However, their contents of ethyl acetate extract($495.2\;{\mu}g/g$, 39.5 g/100g) from fermented tea stored for 1 year had the highest amount among all tested samples. Catechins of fermented tea were found to be EGC, GC, catechin, catechol and EGCG. However, they were not detected in hot water extract. Scavenging activities of DPPH free radical of all extracts from fermented tea were increased in proportion to their concentration and were $72.4\%$ for fermented tea and $80.9\%$ for fermented tea stored for 1 year. Reducing power of ethanol extract at $500\;{\mu}g/mL$ were 0.78 as OD value of 700 nm for fermented tea and 0.88 for fermented tea stored for 1 year, respectively. Antioxidant activities of ethyl acetate extracts at $3000\;{\mu}g/mL$ were $86.6\%$ for fermented tea and $73.7\%$ for fermented tea stored for 1 year, respectively.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.46-51
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• 1996

The in vitro activity of LB 10517, a new catechol-substituted cephalosporin, was compared with those of E-1077, cefpirome and ceftazidime 1034 clinical isolates collected in Japan. LB10517 showed a broad-spectrum antibacterial activity against a wide range of grampositive and gram-negative bacteria including non-glucose fermenting rods, Pseudomonas aeruginosa. Against the methicillin-susceptible strains of Staphylococcus aureus (MSSA) and Strptoccus pyogenes, the $MIC_{90}$ values of LB10517 which required to inhibit 90% of the strains wre $3.13\mug/ml\; and\; 0.1\mug/ml$, respectively. It was as active as E-1077 but more active than cefpirome and ceftazidime. Methicillin-resistant strains of S.aureus (MRSA) and Enterococcus spp. were highly resistant to all the test compunds. LB10517 was highly active against most members of the family Enterobacteriaceae, 90% of which were inhibited at a concentration of less than $0.78\mug/ml$, except for Enterobacter cloacae ($1.56\mug/ml$) and Serratia marcescens ($3.13\mug/ml$)Its activity was comparable to those of E-1077 and cefpirome but it was greater than that of ceftazidime. Against Pseudomonas aeruginosa, LB10517 showed the most potent antibacterial activity among the compounds tested. Ninety percent of P. aeruginosa isolates were susceptible at the concentration of $0.39\mug/ml$. Its activity was 32-to 128 fold higher than those of E-1077, cefpirome and ceftazidime. Against imipenem- or ofloxacin-resistant P. aeruginosa, LB10517 with $MIC_{90}\; of\; 6.25 \\mug/ml\; and\; 3.13\mug/ml$, respectively, showed 16-fold more potent activity than the other test compounds. LB10517 showed a relatively high plasma level and long plasma elimination half-life in rats $(t_{1/2}(\beta,\; 52 min)\; and\; dogs\; (t_{1/2}(\beta),\; 103 min)$.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.778-782
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• 2007

The Diphenyleneiodonium (DPI) is widely used as an inhibitor of flavoenzymes, particularly NADPH oxidase. In this study, we investigated the effect of DPI on the cell growth progression of human colon cancer cells HCT-116 (wild-type p53), HT-29 (p53 mutant) and human breast cancer cells MCF-7 (wild-type p53). DPI treatment in cancer cells evoked a dose- and time-dependent growth inhibition, and also induced the cell cycle arrest in C2/M phase. The peak of cell population arrested in C2/M phase was observed at12 hr after treatment of DPI. In addition, DPI significantly induced the expression of p53, which induces proapoptotic genes in response to DNA damage or irreparable cell cycle arrest, at 6 hr in DPI-stimulated cells. However, a catechol apocynin, which inhibits the assembly of NADPH oxidase, did not induce p53 expression. This suggest that p53 expression induced by DPI is not associated with the inhibition of NADPH oxidase. In conclusion, we suggest that DPI induces the expression of wild-type p53 by ROS-in-dependent mechanism in several cancer cells, and upregulated p53 may be involved in regulatory mechanisms for growth inhibition and cell cycle arrest at C2/M phase in DPI-stimulated cells.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.97-102
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• 2017

Catechol type siderophore different from 2, 3-dihydroxybenzoic acid (DHB) was produced from Acinetobacter sp. B-W grown in medium containing L-glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$. Optimal concentration of glutamic acid for siderophore production was 3% and production of siderophore was decreased above 3% glutamic acid. In previous report, siderophore, 2, 3-DHB was produced from strain B-W grown in medium containing glucose as carbon source and glutamic acid as nitrogen source. Rf value of siderophore produced from strain B-W grown in medium glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$ was 0.32, while 2, 3-DHB was 0.84 in butanol-acetic acid-water (12:3:5) as developing solvent. Antioxidative activity of 2, 3-DHB was not detected in that siderophore produced from glutamic acid. Catechol nature of siderophore was detected by Arnow test. Although in iron-limited media optimal cell growth was identified at $36^{\circ}C$, significant quantities of siderophore were produced only at $28^{\circ}C$. Biosynthesis of siderophore was strongly inhibited by growth at $36^{\circ}C$. Production of siderophore was completely inhibited by $10{\mu}M\;FeCl_3$.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.266-271
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• 2018

Effect of plasmid curing of Acinetobacter sp. B-W on the production of siderophore from glutamic acid as both carbon and nitrogen sole sources was investigated. Plasmid cured mutant of strain B-W lost the ability to produce siderophore from glutamic acid at $28^{\circ}C$. Transformant E. coli $DH5{\alpha}$ harboring 20 kb plasmid, that was isolated from wild type of strain B-W produced siderophore from glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$, but, not at $36^{\circ}C$. Production of siderophore from glutamic acid by transformant E. coli $DH5{\alpha}$ was completely inhibited by $10{\mu}M\;FeCl_3$. In previous report, catechol nature of siderophore produced from glutamic acid by strain B-W was detected by Arnow test. The siderophore produced from glutamic acid by transformant E. coli $DH5{\alpha}$ was also catechol type. Rf value of siderophore produced from transformant E. coli $DH5{\alpha}$ grown in medium glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$ was 0.32 in butanol-acetic acid-water (12:3:5) as developing solvent. Rf value of the siderophore was the same with that of wild type of strain B-W. Thus a single plasmid of 20 kb seemed to be involved in the production of siderophore from glutamic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.316-322
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• 1983

In order to obtain elementary data of enzymatic browning of apples and apple products and to examine effectively inhibitory method of browning, we extracted polyphenol oxidase (EC 1.10.3.1) from apple (Ralls Janet) and investigated its general properties. The optimum conditions for the enzyme reaction were pH 6.0 and temperature of $30^{\circ}C$. The enzyme was very stable at pH 4.0, and at the range of pH 5.0-9.0 its activity was above 80% compared with pH 4.0. The enzyme was very stable by heating at $40^{\circ}C$ for 1 hour, and almost 50% of enzyme activity was lost by heating at $60^{\circ}C$ for 30 minutes. The polyphenol oxidase activity was enhanced by the addition of $Cu^{2+}$ and $Mn^{2+}$, respectively, meanwhile $Na^+$, $Hg^{2+}$ and $Co^{2+}$ inhibited the enzyme activity. The enzyme activity was greatly decreased in the presence of inhibitors such as cysteine, sodium metabisulfite and ascorbic acid. The polyphenol oxidase greatly catalyzed the oxidation of o-diphenols such as chlorogenic acid and catechol, which suggests that main substrate of polyphenol oxidase is o-diphenol compounds.

• Conservation Science in Museum
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• v.30
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• pp.47-70
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• 2023

In 2019, the first excavation survey was conducted at the Temple Site No. 4 of Yaksugok Vally in Namsan Mountain, Gyeongju to determine the original location of the headless stone Buddha statue and the structure of the temple site. The survey excavated a stone Buddha head that was confirmed in a comparative analysis to be petrologically and mineralogically identical to a headless stone seated Buddha statue found derelict nearby. Traces of gold leaf and black adhesive were found on a portion of the right side of the face of the Buddha head buried in the ground. Since it is exceedingly rare for lacquer and gilding techniques to have been applied to a large stone Buddha statue without a base layer, this study examines the gilding techniques of the time by analyzing the characteristics of the materials used. In this process, the structure of the gold foil was observed through analytical microscopy and scanning electron microscopy with energy dispersive X-ray spectrometry, and the gold (Au) component was identified. As a result of analyzing the black adhesive using pyrolysis-gas chromatograph/mass spectrometry (pyrolysis-GC/MS), pyrolysis compounds such as hydrocarbons, fatty acids, catechol, and catechol oxidation products were detected. This was identical to the characteristics identified upon analyzing lacquer collected from species of lacquer tree whose main component is urushiol. Therefore, it was confirmed that the stone Buddha head excavated from the Temple Site No. 4 of Yaksugok Valley was separated from a nearby stone seated Buddha statue, and that the gold foil was attached using lacquer sap collected from lacquer trees, which grow in Korea, China, and Japan.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2131-2133
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• 2004

모세관 전기영동 및 전기화학적 검출 시스템을 마이크로 시스템에 적용하여 ITO 유리기판과 polydimethylsiloxane (PDMS)로 제작하였다. 제작된 모세관 전기영동 및 전기화학적 검출 시스템은 일회용으로 사용가능하며 전기화학적 검출에 아주 적합한 특성을 보인다. 모세관 전기영동 및 전기화학적 검출 시스템은 주입과 분리 채널 (80 ${\mu}m$ 폭 ${\sim}$ 40 ${\mu}m$ 깊이)을 가진 PDMS 층과 유리기판 위에 검출 전극으로 사용되는 ITO가 형성된 층으로 구성된다. PDMS 층과 ITO 유리 기판은 UV-$O_3$ cleaner를 사용하여 접합하였다. 완충용액은 10 mM 2-(N-morpholino)ethanesulfonic acid (MES)를 사용하였고 분석물질은 1 mM 농도의 dopamine과 1 mM 농도의 catechol을 사용하였다. 60 V/cm 전계로 주입 및 분리를 하였으며 작업전극과 기준전극 간의 전위는 +600 mV로 유지하며 분석물질의 농도에 비례하는 전류량법으로 측정하였다. 전기화학적 검출 회로는 천기영동 전계의 간섭으로부터 분리하였다. 10 mM MES 완충용액에서 바탕 전류의 크기가 ${\sim}$10 pA 일 때 측정전류 값은 10 nA이다. 측정된 피크 값은 기존의 Au 전극과 비교하여 선택성, 감도, 분해능이 유사한 특성을 보여준다.

• BMB Reports
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• v.45 no.3
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• pp.200-205
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• 2012

Enzymatic oxidation of commercially available pyrogallol was efficiently transformed to an oxidative product, purpurogallin. Purpurogallin plays an important role in inhibiting glutathione S-transferase, xanthine oxidase, catechol O-methyltransferase activities and is effective in the cell protection of several cell types. However, the anti-inflammatory functions of purpurogallin are not well studied. Here, we determined the effects of purpurogallin on lipopolysaccharide (LPS)-mediated proinflammatory responses. The results showed that purpurogallin inhibited LPS-mediated barrier hyper-permeability, monocyte adhesion and migration and such inhibitory effects were significantly correlated with the inhibitory functions of purpurogallin on LPS-mediated cell adhesion molecules (vascular cell adhesion molecules, intracellular cell adhesion molecule, E-selectin). Furthermore, LPS-mediated nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) releases from HUVECs were inhibited by purpurogallin. Given these results, purpurogallin showed its anti-inflammatory activities and could be a candidate as a therapeutic agent for various systemic inflammatory diseases.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1755-1762
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• 2013

A graphene-Zn/Al layered double hydroxide composite film was simultaneously prepared by electrochemical deposition on the surface of a glassy carbon electrode (G-LDH/GCE) from the mixture solution containing GO and nitrate salts of $Zn^{2+}$ and $Al^{3+}$. The modified electrode showed good electrochemical performances toward the simultaneous electrochemical detection of hydroquinone (HQ), catechol (CA) and resorcinol (RE) due to the unique properties of graphene (G) and LDH such as large active surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of G-LDH/GCE were investigated with cyclic voltammetry and differential pulse voltammetry. The well-separated oxidation peak potentials, corresponding to the oxidation of HQ, CA and RE, were observed at 0.126 V, 0.228 V and 0.620 V respectively. The amperometric response of the modified electrode exhibited that HQ can be detected without interference of CA and RE. Under the optimized conditions, the oxidation peak current of HQ is linear with the concentration of HQ from 6.0 ${\mu}M$ to 325.0 ${\mu}M$ with the detection limit of 0.077 ${\mu}M$ (S/N=3). The modified electrode was successfully applied to the direct determination of HQ in a local tap water, showing reliable recovery data.