• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1386-1391
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• 1999

The methanol extract of Gardenia jasminoides Ellis showed antimicrobial activity against bacteria and yeasts. The extract was successively purified with solvent fractionation, silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, octadecylsilane column chromatography. The purified active substance was isolated by high performance liquid chromatography. The isolated compound was 3,4-dihydroxybenzoic acid which was determined by mass spectrometer, gas chromatograph-mass spectrometer, $^{1}H-nuclear$ magnetic resonance, $^{13}C-nuclear$ magnetic resonance and two-dimensional nuclear magnetic resonance. The content of 3,4-dihydroxybenzoic acid was $32.7\;{\mu}g/g$ in dried fruits of Gardenia jasminoides Ellis.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.807-812
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• 1995

The methanol extracts of Aralia elata bark showed antimicrobial activities against bacteria, yeast, fungi. The solvent fractionated acidic fraction that showed the activity was then successively purified with silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, silica gel partition column chromatography, HPLC and TLC. The isolated major active substance was identified as 3,4-dihydroxybenzoic acid by MS, GC-MS, IR, $^{1}H-NMR\;and\;^{13}C-NMR$. The content of 3,4-dihydroxybenzoic acid was 0.869㎎/g in dried bark of Aralia elata.

• Korean Journal of Pharmacognosy
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• v.19 no.2
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• pp.99-101
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• 1988

3, 4-Dihydroxybenzoic acid and it's artefact ethyl ester obtained from Acanthopanax senticosus Max. were tested ex vivo and found to show mild inhibitory activities against rat platelet aggregation.

• Mass Spectrometry Letters
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• v.4 no.2
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• pp.38-40
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• 2013

Glycans released from ovalbumin by PNGase F were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry using three different dihydroxybenzoic acid (DHB) matrix systems: 2,5-DHB, 2,6-DHB, and a 2,5-DHB/2,6-DHB binary matrix. Relative to the results obtained with the single-component matrices (2,5-DHB or 2,6-DHB), the 2,5-DHB/2,6-DHB binary matrix boasted lower background noise and higher sensitivity. A total of 16 glycan peaks were observed using the 2,5-DHB/2,6-DHB binary matrix, while only 10 and 9 glycan peaks were observed using the 2,5-DHB and 2,6-DHB matrices, respectively.

• Food Science and Preservation
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• v.19 no.2
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• pp.229-234
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• 2012

The antioxidant substance in black onion was identified. The assays that used 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazo line-6-sulphonic acid) ($ABTS^+$) radicals showed that the ethyl acetate fraction of black onion methanol extract had a higher level of radical-scavenging activity than the other fractions. Two antioxidative compounds were purified and isolated from the ethyl acetate fraction via column chromatographies of silica gel and Sephadex LH-20 using the guided DPPH radical-scavenging assay. The isolated compounds were identified as 3,4-dihydroxybenzoic acid (1) and quercetin (2) based on mass spectrometry and nuclear magnetic resonance. The isolated compounds showed a high level of DPPH and ABTS+ radical-scavenging activity. Compound 2 had a higher level of radical-scavenging activity than 1.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.249-255
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• 2015

A soil microorganism producing iron chelator (siderophore) under low iron stress (up to $2{\mu}M$ of iron) was identified as Acinetobacter sp. B-W by 16S rDNA sequence analysis, biochemical-, physiological tests and morphological analysis using electron microscope. Catechol nature of siderophore was detected by Arnow test. Although optimal cell growth was identified at $36^{\circ}C$ in iron-limited media, 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 $10{\mu}M\;FeCl_3$. Iron chelator produced from Acinetobacter sp. B-W was purified from supernatant using butanol extraction, Sephadex LH-20 column chromatography and HPLC. Purified sideropore was identified as 2,3-dihydroxybenzoic acid by HPLC, TLC and IR analysis.

• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.130-133
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• 2003

3,4-dihydroxybenzoic acid(3,4-DHBA) was electropolymerized on glassy carbon electrode to give the GC/p-3,4-DHBA type electrode which was modified with dopamine by the help of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride(EDC) acting as a coupling agent. The carboxylic sites on the polymeric surface of p-3,4-DHBA and mine group at the dopamine gave a QCA(Au)/p-3,4-DHBA-dopamine type of modified electrodes. The o-quinone moieties at the electrode surface exhibited high selectivity to titanium ions in solution. The redox process of the electrode is hydroquinone : quinone +$2H^+2e^-$, which had two strong and two weak pairs of peaks at CV. The modified electrode can deposit Ti(IV) ions as much as $4.13\times10^{-5}gcm^{-2}$. The calibration curve of the electrodes, log of the surface coverage-normalized redox response vs log[Ti], exhibited an excellent correlation$(r{\geq}0.997)$ for titanium concentrations ranging from $5.25\times10^{-4}\;to\;5.25\tiems10^{-8}M.$.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.378.2-378.2
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• 2002

Phellinus linteus has been used as anti-tumor and immuno stimulating agents in folk remedies. From precipitate of MeOH ex. by activited guided fractionation. 5.8-epidioxy ergosta-6.22-dien-3ol. palmitic acid. linoleic acid, and methyl linolate. 3.4-dihydroxybenzoic acid methylester and 4-(3'4'-Dihydroxyphenyl)-3-butene-2one were isolated. DPPH method was used to examine of antioxidative activity of the isolated compounds. As the result, 3.4-dihydroxybenzoic acid methylester, and phenolic compound. 4-(3'4'-Dihydroxyphenyl) -3-butene-2one were found to be a scavenger of 1,1-diphenyl-2-picrylhydrzyl radical. (omitted)

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.898-904
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• 2002

The ehtyl acetate-soluble acidic fractions from juice and cake of Rubrs coreanum fruit showed DPPH radical-scavenging activity. Each fraction was purified through silica gel adsorption column chromatography. The compounds in the ethyl acetate-soluble acidic fraction of juice were identified as 4-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, and 3,4-dihydroxycinnamic acid by GC-MS. The compounds in the ethyl acetate-soluble acidic fraction of cake were also identified as succinic acid, 3,4-dihydroxybenzoic acid, citric acid, 3,4,5,-trihydroxybenzoic acid, and 3,4-dihydroxycinnamic acid by GC-MS. Antioxidative activity of the identified compounds were evaluated by DPPH radical-scavenging assay and hydroxyl radical-scavenging activity assay.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1127-1130
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• 2009

The effects of different dihydroxybenzoic acid (DHB) isomers, when used as matrix materials in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), were investigated in analyses of polyethylene glycol (PEG) polymers. PEG polymers ranging from 400 to 8,000 Da were prepared in different DHB isomer matrices using solvent-based and solvent-free methods. PEG samples were detected only in matrices of 2,3-DHB, 2,5-DHB, and 2,6-DHB while the most intense peaks were observed using 2,6-DHB in both solvent-free and solvent-based preparations.