• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.161-167
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• 1986

The smear method developed by Velaskar and Chitre was modified to allow the screening of plant extracts and/or fractions for platelet anti-aggregating activity. The modified smear method was also found suitable for massive screening of pure compounds. Sample fractions prepared from various plant extracts were examined for their effects against ADP, arachidonic acid (AA) or collagen induced platelet aggregations. Several solvent fractions of plant extracts including water fraction prepared from the methanol extract of Acanthopanax sp. was inhibitory against rat platelet aggregations. The activity guided treatments and fractionations of the water fraction from A. senticosus Max yielded two anti-platelet aggregatory substances, 3, 4-dihydroxybenzoic acid (I) and its artefact ethyl 3, 4-dihydroxybenzoate(II). The inhibitory activities of I and II against rat platelet aggregation were compared with that of aspirin, a known inhibitor of platelet aggregation. Discussions also included the results of the investigations on the structural activity relationships among the various dihydroxybenzoic acid derivatives against platelet aggregations induced by either one of ADP, AA or collagen.

• Natural Product Sciences
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• v.6 no.3
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• pp.117-121
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• 2000

The water extract of the aerial parts of Orostachys japonicus A. Berger showed the inhibitory activity against HIV-1 protease. From the same parts of O. Japanicus, 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid and methyl gallate, together with flavonoids, kaempferol, quercetin, kaempferol $3-O-{\beta}-D-glucoside$, kaempferol $3-O-{\beta}-D-galactoside$ and quercetin $3-O-{\beta}-D-glucoside$ were isolated and characterized by spectral data.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.907-911
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• 2013

Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with ${\alpha}$-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of $10^{-5}-10^{-4}$ for peptides and $10^{-8}-10^{-7}$ for matrices are far smaller than $10^{-3}-10^{-1}$ for peptides and $10^{-5}-10^{-3}$ for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.58-64
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• 2004

For the utilization of chestnut inner bark as forest biomass, the diethyl ether solubles of hot water extract from chestnut inner bark was analyzed by HPLC. Each peak was identified by comparing with retention time of standard regents and their purity from obtained UV spectrum by RI detector. Identified 6 compounds were gallic acid, 3,5-dihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid and protocatecualdehyde as phenolic acids and aldehyde, and catechin and epicatechin as flavonoids.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.254-259
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• 2016

Acinetobacter sp. B-W producing siderophore, 2, 3-dihydroxybenzoic acid (DHB) was analyzed for plasmid content. Strain B-W harbored plasmid of 20 kb in size. Growth at $43^{\circ}C$ was effective in producing mutant cured of plasmid of strain B-W. This mutant lost the ability to produce 2, 3-DHB. Formation of siderophore halos on the chrome azurol S (CAS) agar medium was not detected by cured strain B-W. pHs of supernatants of wild type strain B-W and cured mutant grown in glucose and $MnSO_4$ containing medium at $28^{\circ}C$ for 3 days were 4.5 and 8.5, respectively. Antibiotic resistance against ampicillin, actinomycin D, bacitracin, lincomycin, and vancomycin was lost in cured mutant. Plasmid curing of strain B-W resulted in drastic reduction of minimal inhibitory concentration (MIC) of several antibiotics. E. coli $DH5{\alpha}$ was transformed with plasmid isolated from strain B-W. The transformant E. coli $DH5{\alpha}$ harbored a plasmid of the same molecular size as that of the donor plasmid. Transformant E. coli $DH5{\alpha}$ produced 2, 3-DHB and contained antibiotic resistant ability. Thus a single plasmid of 20 kb seemed to be involved in 2, 3-DHB production. Genes encoding resistance to antibiotics were also supposed to be located on this plasmid.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.463-470
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• 2009

Sixteen antioxidative active compounds isolated from the EtOAc layer of MeOH extracts of kochujang, Korean fermented red pepper paste, were structurally elucidated as fumaric acid, methyl succinate, succinic acid furan-2-yl ester methyl ester (gochujangate, a novel compound), 2-hydroxy-3-phenylpropanoic acid, 3,4-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 6,7-dihydroxy-2H-chromen-2-one (esculetin), caffeic acid, cis-p-coumaric acid, trans-p-coumaric acid, daidzin, genistin, apigenin 7-O-$\beta$-D-apiofuranosyl($1{\rightarrow}2$)-$\beta$-D-glucopyranoside, apigenin 7-O-$\beta$-Dglucopyranoside, and quercetin 3-O-$\alpha$-L-rhamnopyranoside by mass spectrometry (MS) and nuclear magnetic resonance (NMR) experiments. These compounds were analyzed for the first time as antioxidants from kochujang.

• Mass Spectrometry Letters
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• v.11 no.1
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• pp.6-9
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• 2020

Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) analysis of ionic liquid matrices (ILMs) prepared using pyridine and dihydroxybenzoic acid (DHB), such as 2,3-DHB and 2,5-DHB, displayed an unconventional peak at m/z 232.0, which was regarded as [DHB+pyridine-H]⁺. The peak at m/z 232.0 was not observed from other ILMs prepared using other DHB isomers, such as 2,4-DHB, 2,6-DHB, 3,4-DHB, and 3,5-DHB. Two requirements to observe the peak at m/z 232.0 in a DHB/pyridine ILM are suggested. First, carboxyl and hydroxyl groups must be located ortho to each other. Second, the secondary hydroxyl group must be located at a carbon with a high electron density. Based on these two requirements, a potential mechanism for the generation of the peak at m/z 232.0 is suggested.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.71-78
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• 2005

For the utilization of chestnut inner bark as forest biomass, this studies have been carried out cleary investigated about phenolic compounds from the diethyl ether solubles and ethyl acetate solubles of hot water extract from chestnut inner bark. 3 compound were isolated and their structures were identified by spectroscopic methods. They were known compounds, 3,5-dihydroxybenzoic acid, 3,4,5-trihydrixybenzoic acid and catechin. Electron donating ability (EDA) of 3 compounds were investigated. Gallic acid and catechin were found to higher EDA than control, ascorbic acid and $\alpha$-tocopherol in 10 ppm, and especially gallic acid has very higher EDA, 21 times than ascorbic acid. This gallic acid of chemical structure were substituted with free phenolic hydroxyl groups at meta and para position. It was supposed that phenolic hydroxyl groups in chemical structure was a EDA factor.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.358-361
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• 2007

The heartwoods of Rhus verniciflua was extracted with $H_2O$ and the concentrated extract was partitioned with $CHCl_3$, EtOAc, n-BuOH and $H_2O$, successively. From the EtOAc and n-BuOH fractions, four compounds were isolated through the repeated silica gel, ODS and Sephadex LH-20 column chromatographies. They were determined as sinapyl aldehyde (1), 2,4-dihydroxybenzaldehyde (2), 2,4-dihydroxybenzoic acid (3) and 2,4-dihydroxyphenylglyoxylic acid (4) on the basis of spectroscopic data, respectively. Among the isolated compounds, sinapyl aldehyde $(34.7{\pm}0.6%)$ and 2,4-dihydroxyphenylglyoxylic acid $(43.8{\pm}0.9%)$ showed the strong antioxidative activity than artificial antioxidant BHT $(14.4{\pm}0.3%)$ in DPPH radical scavenging activity.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.320-323
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• 2004

Five compounds were isolated from the whole plant of Arabis glabra (Cruciferae) through repeated silica gel and Sephadex LH-20 column chromatography. Their chemical structure were elucidated as salicylic acid, 2,5-dihydroxybenzoic acid, astragalin, rutin, and $quercetin-3,7-O-{\beta}-D-diglucopyranoside$ by spectroscopic analysis.