• Natural Product Sciences
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• v.23 no.1
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• pp.5-8
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• 2017

An antimicrobial compound has been isolated from the leaves of Glochidion superbum. The compound was determined as methyl 3, 4, 5-trihydroxybenzoate (methyl gallate), based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis. The isolated compound exhibited potent antimicrobial activity against three clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) by qualitative agar disc diffusion method and quantitative broth dilution method. Agar disc diffusion was done in a dose-dependent manner for each bacterial isolate at disc potencies of 25, 50, 100, and $150{\mu}g/disc$. The zones of inhibition were on average equal to 12.27, 14.20, 15.43, and 24.17 mm respectively. The inhibition zones were compared with that of vancomycin disc at $30{\mu}g$ as a reference standard. The MIC and MBC values were $50{\mu}g/ml$ and $100{\mu}g/ml$ respectively. The results of anti MRSA activity were analyzed using one-way ANOVA with Turkey's HSD and Duncan test. In conclusion, methyl gallate which was isolated from G. superbum showed the inhibition activity against methicillin resistant S. aureus.

• Bulletin of the Korean Chemical Society
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• v.24 no.3
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• pp.334-338
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• 2003

A simple synthetic method for haptens of organophosphorus (OP) pesticides with a spacer arm (aminocarboxylic acid) attached at the pesticide thiophosphate group was developed and was applied to the synthesis of haptens for the OP fungicide tolclofos-methyl. Using the haptens, a selective enzyme-linked immunosorbent assay (ELISA) for tolclofos-methyl was developed. One of the haptens was coupled to BSA to use as an immunogen. Rabbits were immunized with this conjugate to obtain polyclonal antibodies to tolclofos-methyl. The antisera were screened against another hapten coupled to ovalbumin (OVA). Using the serum with highest specificity, an antigen-coated ELISA was developed, which showed an $IC_{50}$ of 160 ng/mL with the detection limit of 20 ng/mL. The antibodies showed negligible cross-reactivity with other OP pesticides. An antibody-coated ELISA was also developed, which showed an $IC_{50}$ of 410 ng/mL with a detection limit of 130 ng/mL.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1101-1107
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• 2013

In this study, total mercury and methyl mercury in whole blood of Korean was analyzed so as to investigate the correlation between total mercury (T-Hg) and methyl mercury (Me-Hg). 4000 whole blood samples were divided in four groups, according to T-Hg concentration in percentile: group I (p25-p50), group II (p50-p75), group III (p75-p95) and group IV (p95-p100). 100 samples were randomly selected from the each group, and Me-Hg concentration was measured. T-Hg concentration in whole blood was analyzed using a Direct Mercury Analyzer-80 and obtained limit of detection (LOD) was $0.2{\mu}gL^{-1}$. Me-Hg concentration was analyzed with ethylate derivatization using headspace-gas chromatography-mass spectrometry, and obtained LOD of methyl mercury was $0.5{\mu}gL^{-1}$. The geometric means of T-Hg and Me-Hg were $6.35{\mu}gL^{-1}$ and $4.44{\mu}gL^{-1}$, respectively, and 71.91% of T-Hg was presented as Me-Hg.

• Korean Journal of Materials Research
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• v.27 no.4
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• pp.199-205
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• 2017

In this study, (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate acrylate was synthesized by reacting (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate with acrylic acid to minimize hardening shrinkage and to improve heat resistance, which are known as disadvantages of photopolymers for 3D printing application. Urethane acrylate was synthesized by reacting 1,3,5-triazine-2,4,6-triamino alcohol, 2-hexylethyl acrylate, and isophorone diisocyanate in order to improve the mechanical properties without deteriorating the heat resistance. The physical properties before and after the synthesis of the acrylate and the mechanical properties when the urethane acrylate was applied were investigated. The reaction progress of the composite was examined by FTIR and $^{13}C$ NMR. The heat deflection temperature, flexural strength, and surface hardness of the molding were measured. The curing behavior by Photo-DSC ultraviolet irradiation was also examined.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.875-880
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• 2010

Bacterial enoyl-ACP reductase (FabI) has been demonstrated to be a novel antibacterial target. In the course of our screening for FabI inhibitors, we isolated two methyl-branched fatty acids from Streptomyces sp. A251. They were identified as 14-methyl-9(Z)-pentadecenoic acid and 15-methyl-9(Z)-hexadecenoic acid by MS and NMR spectral data. These compounds inhibited Staphylococcus aureus FabI with $IC_{50}$ values of 16.0 and $16.3\;{\mu}M$, respectively, but did not affect FabK, an enoyl-ACP reductase of Streptococcus pneumonia, at $100\;{\mu}M$. Consistent with their selective inhibition for FabI, they blocked intracellular fatty acid synthesis as well as the growth of S. aureus, but did not inhibit the growth of S. pneumonia. Additionally, these compounds showed reduced antibacterial activity against fabI-overexpressing S. aureus, compared with the wild-type strain. These results demonstrate that the methylbranched fatty acids show antibacterial activity by inhibiting FabI in vivo.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1817-1821
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• 2004

Fourier transform Raman spectra of methyl red adsorbed on untreated and pretreated ${\gamma}$-alumina and silicaalumina calcined at 900 $^{\circ}C$ under 1 atm steam flowing were recorded. Spectral analysis shows that the active species adsorbed on ${\gamma}$-alumina was to be deprotonated methyl red, and on silica-alumina to be di-protonated. This indicates that ${\gamma}$-alumina adapted in this work holds Bronsted basicity, and silica-alumina Bronsted acidity. Raman intensities of methyl red on pretreated ${\gamma}$-alumina are about three times stronger than on untreated ${\gamma}$-alumina, while spectral features are unchanged. For silica-alumina, spectral features show modified vibrational characteristics upon surface hydroxylations generated from pretreatment. Consequently, the acidity loss for silica-alumina and the basicity gain for ${\gamma}$-alumina were observed by increasing the surface hydroxyl groups on the catalysts through pretreatment of the steam calcination.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.775-783
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• 2005

The ethanol extract of the peony root (Paeonia Lactiflora Pall, Paeoniaceae) as well as its major active components including gallic acid and methyl gallate were evaluated for their protective effects against free radical generation and lipid peroxidation. In addition, the protective effects against hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line were examined. The ethanol extracts of the peony root (PREs) and its active constituents, gallic acid and methyl gallate, exhibited a significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and had an inhibitory effect on lipid peroxidation, as measured by the level of malondialdehyde (MDA) formation. The PREs did not have any pro-oxidant effect. They strongly inhibited the hydrogen peroxide-induced DNA damage from NIH/3T3 fibroblasts, as assessed by single cell gel electrophoresis. Furthermore, the oral administration of 50% PRE (50% ethanol extract of peony root), gallic acid and methyl gallate potently inhibited the formation of micronucleated reticulocytes (MNRET) in the mouse peripheral blood induced by a $KBrO_3$ treatment in vivo. Therefore, PREs containing gallic acid and methyl gallate may be a useful antigenotoxic antioxidant by scavenging free radicals, inhibiting lipid peroxidation and protecting against oxidative DNA damage without exhibiting any pro-oxidant effect.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.23-28
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• 2007

A linear correlation was found by stepwise multiple regression analysis between the sensory score of barley bran sauce aroma and the absolute gas chromatogram (GC) data transformed with square root. In spite of highly significant relationship between the quantity of the peak and the sensory score, it is difficult to estimate the aroma quality of barley bran sauce samples on the basis of only one peak. Peak 29 (methyl 9,12,15-octadecatrienoate) contributed most to the aroma of barley bran sauce. This was followed by 27 (methyl 9,12-octadecadienoate), 28 (ethyl 9,12-octadecadienoate), 12 (phenyl acetaldehyde), and 9 (methyl furfural) in terms of absolute value. When it was calculated using absolute value transformed by square root, peak 28 (ethyl 9,12-octadecadienoate) made the highest contribution to the aroma of barley bran sauce of among the peaks. It was followed by 31 (9,12-octadecadienoic acid), 27 (methyl 9,12-octadecadienoate), 12 (phenyl acetaldehyde), and 29 (methyl 9,12,15-octadecatrienoate).

• Molecules and Cells
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• v.41 no.8
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• pp.724-732
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• 2018

Plant defence responses to various biotic stresses via systemic acquired resistance (SAR) are induced by avirulent pathogens and chemical compounds, including certain plant hormones in volatile form, such as methyl salicylate and methyl jasmonate. SAR refers to the observation that, when a local part of a plant is exposed to elicitors, the entire plant exhibits a resistance response. In the natural environment, plants are continuously exposed to avirulent pathogens that induce SAR and volatile emissions affecting neighbouring plants as well as the plant itself. However, the underlying mechanism has not been intensively studied. In this study, we evaluated whether plants "memorise" the previous activation of plant immunity when exposed repeatedly to plant defensive volatiles such as methyl salicylate and methyl jasmonate. We hypothesised that stronger SAR responses would occur in plants treated with repeated applications of the volatile plant defence compound MeSA than in those exposed to a single or no treatment. Nicotiana benthamiana seedlings subjected to repeated applications of MeSA exhibited greater protection against Pseudomonas syringae pv. tabaci and Pectobacterium carotovorum subsp. carotovorum than the control. The increase in SAR capacity in response to repeated MeSA treatment was confirmed by analysing the defence priming of the expression of N. benthamiana Pathogenesis-Related 1a (NbPR1a) and NbPR2 by quantitative reverse-transcription PCR compared with the control. We propose the concept of plant memory of plant defence volatiles and suggest that SAR is strengthened by the repeated perception of volatile compounds in plants.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.50-54
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• 2004

To examine the danger of explosion caused by decomposition explosion of Methyl Ethyl Ketone Peroxide, the mini cup pressure vessel tester (MCPVT) was used in the experiment. The maximum explosion pressure increased as the amount of $98\%H_2SO_4$ added to MEKPO increased from $0\%$ to $1\%,\;3\%$, and $5\%$, and the maximum pressure rising velocity increased as well. In addition, the temperature under the pressure at which decomposition starts decreased from $168.16^{\circ}C$ to $126.76^{\circ}C,\;91.21^{\circ}C$, and $81.25^{\circ}C$ as the amount of $H_2SO_4$ added increased.