• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.spc1
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• pp.346-351
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• 2004

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.308-309
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• 2005

• Journal of Life Science
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• v.18 no.2
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• pp.206-212
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• 2008

The quorum sensing (QS) regulatory network has been the subject of extensive studies during recent years and has also attracted a lot of attention because it both positively and negatively regulates various putative virulence factors, although initially considered to be a specialized system of Vibrio fischeri and related species. In this study, to identify the novel materials which inhibit QS system of microorganisms, extracts of eighteen natural products were tested by bioassay using N-(3-oxohexanoyl)-$_L$-homoserine lactone and N-(3-oxooctanoyl)-$_L$-homoserine lactone synthesized in this experiment and an Agrobacterium tumefaciens NT1 biosensor strain containing a traI::lacZ fusion. The result indicated that the extracts of cabbage, leek, and onion exhibited the QS inhibition activity. Thus, materials contained in the extracts were isolated via recycling preparative HPLC and were purified via a JAIGEL-LS255 column. The common fraction corresponding to a peak of the 83 min point of them quenched the quorum sensing of A. tumefaciens NT1 biosensor strain in ABMM containing X-gal and was designated quorum sensing inhibitor-83 min (QSI-83). The QSI-83 exhibited the heat stability and did not inhibit the growth of A. tumefaciens NTl. Furthermore, thin layer chromatography (TLC) results suggested that these novel materials may be antagonists of N-acyl homoserine lactone or may inhibit the QS autoinducer synthesis by Pseudomonas syringae pv. tabaci.

• Applied Biological Chemistry
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• v.23 no.4
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• pp.206-210
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• 1980

The minor components of $saponin-ginsenoside-Rf,\;-Rg_2\;and\;-Rh_1$ were isolated from Panax ginseng C.A. Meyer by preparative, semi-preparative and analtical high performance liquid chromatography. The rapid method developed in this work was proved to be very effective in separation and isolation of these minor ginsenosides. A further isolation was achieved by using the recycling technique.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.520-522
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• 2008

A new compound named soraphinol C (1) was isolated from myxobacteria Sorangium cellulosum KM1001 a soil isolate, together with a structurally related known compound, 4-hydroxysattabacin (2). These compounds were isolated by silica gel column chromatography and recycling preparative HPLC, consecutively. The structures of the compounds were determined on the basis of combined spectroscopic analyses. Compounds 1 and 2 exhibited antioxidant activity as a radical scavenger in the experiment using a hydrophilic free-radical initiator, 2,2'-azobis(2-amidinopropane)dihydrochloride with ORAC values of 0.956 and 0.617, respectively.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.179-182
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• 2004

Bioassay-directed fractionation of the dried roots of Salvia miltiorrhiza led to the isolation of abietane tanshinones, cryptotanshinone and dibydrotanshinone I. Their structures were elucidated using $^1H-\;and\;^{13}C-NMR$, UV, IR and mass spectral analyses. These compounds exhibited a moderate antimicrobial activities against Staphylococcus epidemidis, Staphylococcus aureus, and Staphylococcus pyogene.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1122-1127
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• 1997

Melanoidins, which were higher polymers with intense brown color, were investigated on their decolorization and degradation by ozonolysis. Amino acids linked up with melanoidins were readily separated by depolymerization of melanoidins with ozonolysis. The IR spectra of ozone-untreated MRPs showed a higher peak at $1665cm^{-1}$ (C=N) and $1600cm^{-1}$ (C=C) than the corresponding peaks of ozone-treated MRPs. Ozone-treated melanoidins with molecular weight of above 900 showed the highest nitrogen composition of all melanoidins tested. Ozone-treated melanoidins with molecular weight of 900 to 1000 were separated into five peaks on recycling preparative HPLC chromatogram. Major functional groups in ozone-treated melanoidins with molecular weight of 900 to 1, 000 were -CH$_2$-CO-, -CH$_2$-O- and CH$_2$-.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.1-7
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• 2006

Objectives : The purpose of this study is to isolate tyrosinase inhibitory material from Pinellia ternata and characterize its own structure and activity. Methods : Pinellia ternata (600g) was extracted with 95% methanol (1L) at $37^{\circ}C$ for 4 days, with shaking at 250rpm. The extract was further solvent-fractionated with n-hexane, chloroform, ethylacetate and water. The active fraction was subjected to JAI recycling prep-HPLC JAIGEL GS-320 column. The structure was identified for the active peak with NMR and GC. Results : Tyrosinase was potently inhibited by 95% methanol extracts from Pinellia ternata. The $IC_{50}$ value of the extracts was estimated to be 0.05mg/ml. The extracts was divided into four solvent-fractions, and the most potent tyrosinase inhibition was found in ethylacetate layer. $IC_{50}$ value of ethylacetate fraction was 0.001mg/ml. This fraction was further purified with JAI Recycling Preparative HPLC (Model: LC 9104). The isolated compound showing inhibitory activity was characterized on its chemical structure by NMR and the compound was identified as 3,4-dihydroxybenzaldehyde. $IC_{50}$ was found to be 7.74 ${\mu}M$ which is much lower than that of kojic acid $(66.5{\mu}M)$. Conclusions : The data suggest that 3,4-dihydroxybenzaldehyde isolated and identified from Pinellia ternata is very strong inhibitor to melanin biosynthesis.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1032-1037
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• 2008

Lowly volatile heterocyclic sulfur compounds generated in autoclaved garlic extract were isolated and identified, and their antimicrobial activity was determined. Two kinds of unusual volatile sulfur compounds were separated from heated garlic by preparative recycling high performance liquid chromatography (HPLC), and identified by gas chromatography (GC)-mass spectrometry (MS) and $^1H$-nuclear magnetic resonance (NMR). They had heterocyclic structures with 4 to 5 sulfur atoms in the molecules. 4-Methyl-1,2,3-trithiolane (MTTT) is highly volatile and was not able to be concentrated, and was identified by GCMS only. MTTT and 6-methyl-1,2,3,4,5-pentathiepane (MPTP) are lowly volatile and were obtained in pure states to be positively identified for the first time. All 3 heterocyclic sulfur compounds began to appear by the time when the early-formed diallyl sulfides started to disappear. The minimum inhibitory concentration range of MTTT and MPTP was determined to be between 1 and 6 ppm against all yeasts tested. MTTT and MPTP were lowly volatile and sparingly soluble in water.

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.179-187
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• 2009

Five kinds of coumarin compounds were successfully purified from Angelica gigas Nakai by using recyclingpreparative HPLC and identified as decursin (1), decursinol angelate (2), 7-demethylsuberosine (3), marmesin (4), and decursinol (5) by NMR analyses. None of the purified compounds in ethanol showed DPPH radical scavenging activity, while the A. gigas extract (AGNEX) displayed a significant level of activity. Interestingly, compounds 3 in phosphate buffered saline (PBS) showed good $ABTS^+$ radical scavenging activity ($IC_{50}=8.1{\mu}g$/mL) as did compounds 4 and 5. The anti-inflammatory activities of the purified compounds were evaluated and compared using the NO concentration assay and western blot analysis on LPS-stimulated RAW 264.7 cells. NO production was significantly suppressed by all the compounds in a dose-dependent manner among which compounds 1, 2, and 3 showed very good activities with $IC_{50}$ values of 7.4, 6.5, and $7.6{\mu}g$/mL, respectively. Treatment with compounds 1-5 effectively suppressed the expression levels of iNOS, IL-1$\beta$, and COX-2, which are responsible for promoting the inflammatory process. Thus, the ethanol extract and coumarin compounds of A. gigas Nakai hold promise for use as potential anti-inflammatory agents.