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Keun-Hyung Park

Publications and source records attributed to Keun-Hyung Park.

6 recordsLinked to original sources
PubMed2007

Complete 1H and 13C NMR assignments of sesquiterpene glucosides from Ixeris sonchifolia.

Four sesquiterpene glucosides were isolated from Ixeris sonchifolia Hance. The structure of a new compound (1) was assigned as 9beta-monohydroxy-2,12-dioxo-guaia-3,11(13)-dien-1alpha,5alpha,6beta,7alpha,9beta,10alphaH-12,6-olide-9-O-beta-D- glucopyranoside (ixerinoside). In addition, unambiguous and complete assignments of (1)H NMR chemical shifts for crepidiaside A (2), ixerin Z (3), and 11,13alpha-dihydroixerin Z (4) are presented. The assignments were achieved by two-dimensional NMR (gCOSY, gHSQC, gHMBC, NOESY) and one-dimensional nuclear Overhauser effect (NOE) experiments.

Asteraceae↗
PubMed2006

Isolation and characterization of antifungal substances from Burkholderia sp. culture broth.

A new antagonistic Burkholderia strain, designated MP-1 and producing antifungal activities against various filamentous plant pathogenic fungi, was isolated from the rhizoshere in the Naju area. Cultural characteristic studies strongly suggested that this strain belongs to the genus Burkholderia. The nucleotide sequence of the 16S rRNA gene (1491 pb) of strain MP-1 exhibited close similarity (99% to 100%) with other Burkholderia 16S rRNA genes. Extraction of fermentation broth of Burkholderia sp. MP-1 and various separations and purification steps led to isolation of four pure active molecules. The chemical structure of these four compounds-named phenylacetic acid, hydrocinnamic acid, 4-hydroxyphenylacetic acid, and 4-hydroxyphenylacetate methyl ester-was established on the basis on their gas chromatography-electron impact-mass spectrometry (GC-EI-MS) and trimethylsilation GC-EI-MS data. The four isolated compounds inhibited filamentous fungal growth on potato dextrose agar medium supplemented with 100 mg/L of phenylacetic acid, hydrocinnamic acid, 4-hydroxyphenylacetic acid and 4-hydroxyphenylacetate methyl ester individually.

Antifungal Agents↗
PubMed2006

Isolation and characterization of a new compound from Prunus mume fruit that inhibits cancer cells.

An active compound that inhibits cancer cells was isolated from the fruit of Prunus mume, and its structure and in vitro activities were characterized. The n-hexane fraction obtained from methanol extracts exhibited the strongest inhibitory effect on the growth of cancer cells. From the n-hexane fraction, a new compound named B-1 was purified through preparative thin-layer chromatography, ODS column chromatography, and reverse phase high-performance liquid chromatography and its structure was analyzed by fast atom bombardment mass spectrometry and 1H and 13C NMR. The molecular formula of B-1 was C19H22O6 {2-hydroxy-1-[(7-hydroxy-2-oxo-2H-chromen-6-yl)methyl]-2-methylpropyl-(2Z)-3-methyl-but-e-enoate:prunate}, and the IC50 value was in the range of 39-58 microg/mL in descending order of the cancer cell lines Hep-2, SW-156, HEC-1-B, and SK-OV-3. B-1 exhibited 81-96% inhibition at a concentration level of 100 microg/mL against all cells, based on an 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. However, B-1 showed little effect against normal cells with only 23% or less growth inhibition at 100 microg/mL. Thus, B-1 has a highly specific inhibitory effect against cancer cells but little effect against normal cells. When the cancer cell lines Hep-2 and SK-OV-3 were incubated with B-1 for 72 h, most of the tested cells suffered strong growth inhibition. The compound has the potential to be developed as a nutraceutical.

Animals↗
PubMed2006

Protein nanoarray on Prolinker surface constructed by atomic force microscopy dip-pen nanolithography for analysis of protein interaction.

Protein nanoarrays are addressable ensembles of nano-scale protein domain on solid surfaces. This method can serve as a useful platform for ultraminiaturized bioanalysis. In this study, we investigated single molecular nanopatterning and molecular interaction of proteins that were immobilized on Prolinker surface of gold-coated silicon wafer by using dip-pen nanolithography (DPN) method. Contact force and humidity were optimized at 0.01 nN and 80%, respectively. The domain features of protein nanoarrays were developed at the contact time of 5 s. The optimized conditions for the nanoarray process were applied to create protein nanoarray using integrin alpha(v)beta3 and angiogenin. Constructed protein nanoarrays using integrin alpha(v)beta3 have single molecular monolayer with regular domain shape (height 15 +/- 5 nm). The changed height value due to the single molecular interaction between integrin alpha(v)beta3 and vitronectin was approximately 30 +/- 5 nm on Prolinker surface as measured with atomic force microscopy tip. Taken together, these results suggest that protein nanoarray on Prolinker surface fabricated by well-controlled DPN process can be used to analyze single molecular interaction of protein.

Gold↗
PubMed2004

Identification and antimicrobial activity of phenylacetic acid produced by Bacillus licheniformis isolated from fermented soybean, Chungkook-Jang.

A bacterial strain, B65-1, which showed strong antimicrobial activity, was isolated from Chungkook-Jang, a traditional Korean fermented-soybean food with antimicrobial properties. Based on carbon utilization pattern and partial 16S rRNA sequence analysis, the B65-1 strain was identified as Bacillus licheniformis. An antibiotic compound, active against bacteria and yeast such as Staphylococcus aureus, Escherichia coli, and Candida albicans, was isolated by various chromatographic procedures from culture filtrates of B. licheniformis B65-1. The purified antibiotic was identified to be phenylacetic acid, with the molecular formula C(8)H(8)O(2) by analyses of EI-MS and NMR. The phenylacetic acid was detected in fermented soybean made with the strain B65-1 as a starter, but was not present in extracts of nonfermented soybean. Our results indicated that the phenylacetic acid produced by B. licheniformis during fermentation of soybean is one of the main compounds of antimicrobial activity of Chungkook-Jang.

Anti-Bacterial Agents↗