• Natural Product Sciences
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• v.15 no.3
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• pp.144-150
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• 2009

Gradient centrifugal partition chromatography (GCPC) method was developed and applied to isolate 3,5-dimethoxyphenanthrene-2,7-diol (DMP) and batatasin-I (BA-I) from the dichloromethane soluble extract of Dioscorea opposita. In this method, the lower phase of n-hexane-methanol-water system (HMW, 10 : 9 : 1, v/v) was used as a mobile phase A (MpA) and water was used as a mobile phase B (MpB). This gradient CPC method is comparable to that of reversed-phase HPLC method in that the stationary upper-phase of HMW (10 : 9 : 1 v/v) works as if it were reversed-phase silica gel due to its hydrophobic property, while the lower phase (MpA) and water (MpB) functioned as hydrophilic mobile phases. The initial condition of the mobile phase was 20% MpA/80% MpB and maintained for 150 min to obtain DMP (1.2 mg), and then MpA was increased up to 50% to elute BA-I (1.7 mg). The purities of DMP and BA-I were 94.1% and 98.3% with the recovery yields of 83% and 86%, respectively. Similar results were obtained by linear-gradient CPC. The CPC peak fractions were identified by comparing their retention time to those of authentic samples of DMP and BA-I and their spectroscopic data ($^1$H NMR and $^{13}$C NMR) to those of literature values.

• Korean Journal of Microbiology
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• v.24 no.4
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• pp.352-356
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• 1986

A study was carried out to determine the effect of ginseng saponin an its related materials on aflatoxin production by Aspergillus parasiticus NRRL2999 in glucose-salts(GS) medium. Maximal growth of the mold and AF froduction in the medium occurred after 5 and 9 days at $28^{\circ}C$, respectively. When various concentrations of saponin added to the medium aflatoxin synthesis were significantly reduced (p<0.05) compared to the control after 9 days at $28^{\circ}C$. 0.05% of saponin inhibited aflatoxin production most effectively in the low concerntrations of saponin (0.01-0.2%) and the toxin synthesis reduced with an increasing concentrations of saponin in the high concentrations (0.03-5.0%). Various concentrations (0.01-1.0%) of saponin diol and triol in the media also caused to reduce aflatoxin synthesis by the mold (p<0.05). All saponin fractions were found to decrease aflatoxin production significantly. Saponin fraction numbers of 1,2,4 and 6 were shown to reduce aflatoxin production effectively, and the number 1 was the most effective. Addition of 0.05% of nucleic acid related materials to the medium reduced aflatoxin production (p<0.05). Aflatoxins could not be found in broth at all, but in mycelia when 0.05% of caffeine was added to the medium. Aflatoxin synthesis was well correlated with total lipid synthesis, growth and glucose uptake. When aflatoxin synthesis inhibited (5.0% of saponin) both total lipid synthesis and growth were stimulated and the efficiency of glucose utilization was reduced.

• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.47-55
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• 2011

UV-curable coatings have been used in various industries due to their advantages such as high mechanical property, good solvent resistance, fast curing process and low volatile organic compounds. However, a lack of flexibility of UV-cured films is a weak point for the pre-coated system of roll-to-roll process. In this study, UV-curable polycarbonate-based methacrylates were synthesized with polycarbonate diol, isophorone diisocyanate and 2-hydroxyethylmethacrylate to improve flexibility of the UC-cured films. The effects of polyol molecular weight, content of photoinitiator and monomers on the UV-curing behavior, flexibility and properties were investigated. The UV-curing behavior was measured by a photo-DSC, the pendulum hardness, tensile strength, viscoelastic properties were also evaluated.

• Archives of Pharmacal Research
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• v.27 no.3
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• pp.291-294
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• 2004

Activity-guided fractionation of the n-hexane and ${CHCl_3}-soluble$ fractions of Sindora sumatrana using a bioassay based on the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production by inducible nitric oxide synthase (iNOS) in murine macrophage RAW 264.7 cells led to the isolation of the known compound, $(+)-7{\beta}-acetoxy-15,16-epoxy-3$, 13(16), 14-clero-datriene-18-oic acid (2) as an active constituent. In addition, a new trans-clerodane diterpenoid, (+)-2-oxokolavenic acid (1), together with six known compounds, (+)-3, 13-clerodadiene-16,15-olide-18-oic acid (3), $(+)-7{\beta}-acetoxy-3$,13-clerodadiene-16,15-olide-18-oic acid (4), $(+)-7{\beta}-acetoxy-16-hydroxy-3$,13-clerodadiene-16, 15-olide-18-oic acid (5), ${\beta}-caryophyllene$ oxide (6), $clovane-2{\beta},9{\beta}-diol (7),{\;}and{\;}caryolane-1,9{\beta}-diol$ (8) were isolated and found to be inactive. The structure of compound 1 was determined using physical and spectroscopic methods such as 1D and 2D-NMR experiments. The known compounds 2-8 were identified by the spectroscopic data and by comparison with the published values. Of eight isolates (1-8), only compound 2 exhibited an iNOS inhibitory activity with $IC_{50}$/ value of $51.6{\;}\mu\textrm{m}M$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3060-3065
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• 2009

A series of wholly aromatic Poly(ether-ether-ester)s with flexible side chain was synthesized by direct polycondensation from ether linkaged triad diol and 2,5-dialkoxyterephthalic acid. The chemical structures and physical properties of these polymers were investigated by using $^1H$-NMR, FT-IR, DSC and TGA. As results of investigations, the inherent viscosities($\eta$inh) measured at $40^{\circ}C$ in 1,1,2,2-tetrachloroethane(TCE) were 0.45~0.86 dl/g and initial decomposition(Td) in TGA occurred at 378~418 $^{\circ}C$ in N2 gas. The majority of these polymers were soluble in organic solvents used in this experiments at elevated temperatures. Melting temperatures(Tm) decreased with increasing the length of the side chain and showed odd-even effects.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.279-283
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• 2007

Epoxide hydrolase (EH) gene of Caulobacter crescentus was cloned by PCR and expressed in Escherichia coli. The C. crescentus EH (CcEH) primarily attacked at the benzylic carbon of (S)-styrene oxide, while the CcEH preferentially attacked at the terminal carbon of (R)-styrene oxide, thus leading to the formation of (R)-phenyl-1,2-ethanediol as the main product. (R)-phenyl-1,2-ethanediol was obtained with 85% enantiomeric excess and yield of 69% from racemic styrene oxide via enantioconvergent hydrolysis by using recombinant CcEH as the single biocatalyst.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.548-553
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• 2011

NCO terminated polyurethane prepolymers were synthesized from isophorone diisocyanate(IPDI), polycarbonate diol(PCD) and dimethylol propionic acid(DMPA). Subsequently, acrylic terminated polyurethanes were prepared by capping the NCO groups of polyurethane prepolymers with different types of acrylate monomers, such as 2-hydroxyethyl methacrylate(HEMA), 2-hydroxyethyl acrylate(HEA) and pentaerythritol triacrylate(PETA). The average particle sizes of the acrylic terminated polyurethane solutions were increased by capping acrylate monomers. Also, the prepared coating films showed better abrasion resistance and pencil hardness than those of pure waterborne polyurethanes. The coating film with PETA exhibited the best abrasion resistance and pencil hardness of coating films prepared with three acrylate monomers.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.304-310
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• 1986

A. calcoaceticus C10 grown on cyclohexanol as sole source of carbon and energy produced cyclohexanol dehydrogenase(CDH) and glucose dehydrogenase (GDH) concomitantly. CDH and GDH were different in coenzyme, induction and electrophoretic patterns. CDH depended for activity on $NAD^+$ only, while GDH required $NAD^+$ or $NADP^+$ alternatively. CDH was produced in the medium added cyclohexanol, but GDH was produced in various media such as LB, LB added 0.2% glucose or cyclohexanol and cyclohexanol medium. Productivity of CDH in A. calcoaceticus C10 was enhanced about 8 times by the addition of 0.2% cyclohexanol to LB medium after 4 hours as much as LB medium only. Production of CDH was induced by cyclohexanol, cyclohexanone, cyclohexan-1,2-diol and cyclohexene oxide, but not induced by ${\varepsilon}-caprolactone$ and adipate.

• Resources Recycling
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• v.21 no.1
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• pp.41-48
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• 2012

A study on the behavior of boron extraction by TMPD(2,2,4-trimethyl-1,3-pentanediol) was carried out to find the optimum conditions for the boron extraction from brine. In case of boron extraction from 0.736 g/L boron-containing brine, typical optimum extractive conditions would be confirmed to be 0.75 mol/L of extractant concentration at 3.0 pH of brine with 1 of phase ratio and 20 min. of shaking time at 298 K respectively. And 1 mol/L sodium hydroxide of stripping agent was shown above 99 % of boron extraction and stripping efficiencies. Also, extraction equilibrium equation were obtained through experiments as follows : log D = 1.7 log $[TMPD]_O$ + constant at pH < 6.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.347-352
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• 2014

The roots of Pueraria mirifica were extracted with 70% aqueous ethyl alcohol and partitioned into ethyl acetate (EtOAc), n-butyl alcohol (BuOH), and $H_2O$ fractions, successively. From the EtOAc fraction, four norsesquiterpenes were isolated through the repeated silica gel, octadecyl silica gel and Sephadex LH-20 column chromatographies. On the basis of physicochemical and spectroscopic data including nuclear magnetic resonance (NMR), mass spectrometry, and infrared spectroscopy, the chemical structures were identified as megastigm-5-en-3,9-diol (1), linarionoside B (2), 3,5,6,9-tetrahydroxymegastigm-7-ene (3) and 3,4,9-trihydroxymegastigma-5,7-diene (4). Especially, the configuration of the anomer hydroxyl group was determined as a from the coupling constants of the anomer proton (J =8.0 Hz) in the $^1H$-NMR spectrum. These compounds were isolated for the first time from the roots of P. mirifica in this study.