• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.243-250
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• 2006

Three novel potential metal ion chelating units have been synthesized and characterized: 5-hexylcarbamoyl-3,4-dihydroxythiophene-2-carboxylic acid methyl ester (5), 3-benzyloxy-4-hydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (6), and 3,4-dihydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (7). The crystal structure of 6 was obtained and suggests the presence of three distinct intramolecular hydrogen bonds, namely $[N_{amide}-H{\cdot}{\cdot}{\cdot}O]$ $[O-H{\cdot}{\cdot}{\cdot}O_{amide}]$ and $[N_{amide}-H{\cdot}{\cdot}{\cdot}S]$. Boron chelation with 5, 6 and 7 through the use of $BF_3, \;B(OH)_3 \;or \;B(OMe)_3$ was probed by $^1H$, $^{11}B$, and $^{13}C$ NMR spectroscopy. Technetium (I) chelation with 5, 6 and 7 was also studied via HPLC elutions using $[^{99m}Tc(CO)_3(OH_2)_3]^+$.

• Applied Biological Chemistry
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• v.45 no.3
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• pp.168-172
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• 2002

Antioxidative activities of solvent fractions obtained from Korean Rhus vernicifera, being used in food industry and as a traditional medicine, were examined by the methods of DPPH scavenging activity, inhibitory effect on autooxidation of linoleic acid, nitrite scavenging activity and the inhibitory effect on xanthine oxidase activity. Ethyl acetate fraction showed potent antioxidative activities. Three compounds were isolated from the ethyl acetate fraction by rotatory locular counter current chromatography (RLCCC), Sephadex LH-20 column chromatography and HPLC. The isolated compounds were 1,2,3-trihydroxybezene, methyl 3,4,5-trihydroxybenzoate and 3,4,5-trihydroxybenzoic acid determined by GC/MS and, $^1H$ and $^{13}C$ NMR. Among the isolated compounds, methyl 3,4,5-trihydroxybenzoate showed the strongest antioxidative activity than artificial antioxidants, BHA and BHT in various methods. However, these isolated compounds did not show cytotoxicity effects on the human cancer cell lines. Therefore, we may suggest that methyl 3,4,5-trihydroxybenzoate can be used as a food additive possessing the potent antioxidative activity.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1510-1515
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• 2014

Lysobacter capsici YS1215 isolated from soil previously showed nematicidal potential for biological control of the root-knot nematode. In this study, lactic acid, a nematicidal compound, was isolated from culture filtrate of YS1215, and its ovicidal activity was investigated. Purification and identification of lactic acid were performed by a series of column chromatographies and identified by $^1H$ and $^{13}C$ NMR spectra and GC-MS analysis. Our results showed that bacterial culture filtrate containing lactic acid significantly inhibited egg hatching. The lowest egg hatch rate (5.9%) was found at a high concentration ($25 {\mu}l/ml$) of lactic acid at 5 days after incubation, followed by 20 (15.2%), 15 (23.7%), 10 (29.8%), and $5(36.4%){\mu}l/ml$, while egg hatching in the control (sterile distilled water) was 44.5%. This is the first report of lactic acid as an ovicidal compound, and it may be considered as an alternative of chemical pesticide against root-knot nematodes.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.161-166
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• 2013

At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer's disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman's reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor ($IC_{50}$ = 27.1 ${\mu}g/ml$) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and $^1H$- and $^{13}C$-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the $H_2O_2$- and ${\beta}$-amyloid-injured PC12 cells at 1 to 25 ${\mu}g/ml$. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.635-643
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• 2011

Agar was prepared from Gelidium amansii collected from Jeju Island, South Korea. This agar preparation has high gel strength and low sulfate content compared with G. amansii agar from Morocco. Accordingly, agarose was made from the Jeju agar through the consecutive refining processes of dimethyl sulfoxide (DMSO) extraction and ethylene diamine tetra acetic acid (EDTA) washing. The physicochemical properties of the resulting agarose were compared with those from agarose prepared using only DMSO extraction. Consecutive DMSO extraction and EDTA washing more strongly affected the physicochemical properties of the agarose (purified agarose) compared with the use of DMSO extraction alone. These properties were similar to those of commercial agarose used for electrophoresis. In DNA electrophoresis, the separation and movement speed of the purified agarose were similar to those of the commercial agarose. In a $^{13}C$ NMR analysis, the purified agarose exhibited the same carbon peak as the commercial agarose. When observed under scanning electron microscopy, the agar had an even and smooth surface without irregularities or pores, and the purified agarose had a wide surface area with a large number of pores; the commercial agarose had an irregular surface that would allow the solvent to easily permeate. These results illustrate that the physicochemical properties of agarose prepared from DMSO extraction and EDTA washing were more effective than those observed after DMSO extraction alone; thus, these processes used in succession will be useful in agarose industries.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.166-170
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• 2004

Gluconobacter oxydans that produces the cellulose was isolated. In order to confirm the chemical features of cellulose, various spectrophtometeric analysis were carried out using electron microscopy, X-ray diffractogram, and CP/MAS $\^$13/C NMR. The purified cellulose was found to be identical to that of Acetobacter xylinum. For effective production of cellulose, the various carbon and nitrogen sources, mixture of calcium and magnesium ions, and biotin concentration were investigated in flask cultures. Among the various carbon sources, glucose and sucrose were found to be best for the production of cellulose, with maximum concentration of 2.41 g/L obtained when a mixture of 10 g/L of each glucose and sucrose were used. With regard to the nitrogen sources, when 20 g/L of yeast extract was used, the maximum concentration of bacterial cellulose was reached. The concentration of cellulose was increased with mixture of 2 mM of each Ca$\^$2+/ and Mg$\^$2+/. The optimum biotin concentration for the production of cellulose was in the range of 15 to 20mg/L. At higher biotin concentration (25-35mg/L). the bacterial cellulose production was lower.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.873-881
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• 2009

Bis(phenylethynyl)dimethylsilane is branched by the hydrosilation of the phenylethynyl group with dichloromethylsilane, and then the resulting chlorosilane is reacted with lithium phenylacetylide to give the $1^{st}$ generation. The same hydrosilation and alkynylation are repeated to obtain the $7^{th}$ generation. In addition peripheral Si-Cl moiety of the seven kind generation dendrimers are reacted with alcoholic moiety of 9-hydroxymethylanthracene and 2-(2-hydroxyphenyl)benzoxazole group in the presence of TMEDA. Then three kinds of carbosilane dendrimers are prepared from the $1^{st}$ to the $7^{th}$ generations, the $7^{th}$ generation of each dendrimer has 256 phenylethynyl, 256 9-anthracenylmethoxy, or 128 2-(2-phenoxy)benzoxazole groups. Each synthesized dendrimer is unequivocally characterized by $^1H\;and\;^{13}C\;NMR$, elemental analysis, MALDI-MS, GPC, and PL (photoluminescence). Characteristically PDI (Polydisperse Index) values of the dendrimers’ peak in GPC are in the range of $1.00{\sim}1.07$, which indicates that each generation of carbosilane is in unified distribution. PL spectra of phenylethynyl and 9- anthracenemethoxy group substituted dendrimers show no significant change with increasing the generation from the $1^{st}$ to the $7^{th}$. However, the PL spectra of 2-(2-phenoxy)benzoxazole group substituted dendrimers show a blue-shift trend with increasing the generation from the $1^{st}$ to the $7^{th}$.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.999-1004
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• 2007

Spherical porous silica supports modified with titanium or zirconium alkoxides were prepared, and allyl groups were chemically attached to the titanized or zirconized silica supports, and the product was cross-polymerized with a double bond containing cellulose derivative to yield new CSPs (chiral stationary phases). Magic angle spinning 13C solid state NMR and elemental analysis were used to characterize the CSPs. The performances of the chiral stationary phases were examined in comparison with a conventional chiral stationary phase. Spherical porous silica particles modified with 3,5-dimethylphenylcarbamate of cellulose were prepared and used as the conventional chiral stationary phase. Chromatographic data were collected for a few pairs of enantionmers in heptane/2-propanol mixed solvents of various compositions with the three chiral columns and the results were comparatively studied. The separation performance of the chrial phase made of the titanized silica was better than the others, and the separation performance of the chiral phase of the zirconized silica was comparable to that of the conventional chiral phase. The superiority of titanized silica over bare or zirconized silica in chiral separation seemed to be owing to the better yield of crosslinking (monitored by increase of carbon load) for titanized silica than for the others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.511-515
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• 2002

Paeoniae radix has been considered as one of the most important crude drugs used in traditional oriental medicine and has been employed as a circulatory tonic in care of weakness, night sweats, and lumbar pain, etc. Platelet activation plays an important role in thrombosis and haemostasis. Active compounds for the inhibition of platelet activation from Paeoniae radix were extracted and fractionated into five fractions. Its fraction two and three of ethyl acetate extract inhibited the aggregation of washed rabbit platelets induced by collagen. Two active compounds, bezoyloxypaeoniflorin and paeoniflorin, were isolated from fraction two and three by silica gel column and high performance liquid chromatography. The chemical structures were determined by comparison of their proton and carbon nuclear magnetic resonance spectra. Benzoyloxypaeoniflorin showed strong inhibition at the concentration of 100 ug/mL against collagen-induced washed rabbit platelets aggregation. It is suggested that Paeoniae radix has become food material to prevent a cardiovascular disease.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.798-803
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• 1999

Prolyl endopeptidase [PEP; EC 3.4.21.26], a serine protease which is known to cleave peptide bonds on the carboxy side of a proline residue, plays an important role in the degradation of proline-containing neuropeptides that have been suggested to participate in learning and memory processes. An abnormal increase in the level of PEP, which can lead to generation of $A{\beta}$, is also suggested to be involved in Alzheimer's type senile dementia. In the course of screening PEP inhibitors from Basidiomycetes, the mushroom Polyozellus multiplex exhibited a high inhibitory activity against PEP. Two active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification, using silica gel, Sephadex LH-20, and Lobar RP-18 chromatography. The chemical structures of these compounds were identified as thelephoric acid and 12-acety1-2,3,7,8-tetrahydroxy-[12H]-12-hydroxymethylbenzobis[I.2b,3.4b'] benzofuran-11-one (kynapcin-9) by spectral data including UV, IR, MS, HR-MS, $^1H-,{\;}^{13}C-$, and 2D-NMR. The $IC_{50}$ values of the thelephoric acid and kynapcin-9 were 0.157 ppm (446nM) and 0.087 ppm (212nM) and their inhibitor constants ($K_i$) were 0.73ppm ($2.09{\;}\mu\textrm{m}$) and 0.060 ppm (146 nM), respectively. Furthermore, they were non-competitive with a substrate in Dixon plots.