• Journal of Photoscience
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• v.10 no.2
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• pp.181-184
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• 2003

Photochemical reactions of some organic molecules on titanium dioxide were investigated in methanol. A methanolic solution of trans-cinnamic acid and titanium dioxide was irradiated with 300 nm UV lamps for 24 h to afford methyl cinnamate. In the case of trans-cinnamamide, the major product was found to be 3-phenylpropionamide, i.e., a saturation product of ethylenic double bond. However, irradiation of urocanic acid, caffeic acid, ethyl cinnamate, trans-chalcone, trans-cinnamonitrile, trans-stilbene or trans, trans-1,4-diphenyl-1,3-butadiene on titanium dioxide under the same conditions did not give any noticeable products. Meanwhile, when irradiated some aromatic aldehydes, such as trans-cinnamaldehyde, l-naphthaldehyde, and 2-naphthaldehyde in methanol, vicinal diols and alcohols derived from the diols were produced. On the other hand, irradiation of 9-anthraldehyde and titanium dioxide in methanol afforded only alcohols, in which diol was not observed.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.149-154
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• 1996

A high-performance liquid chromatographic method for the determination of ${\beta}$-sitosterol in the unsaponifiable fraction of Zea mays L. and its related drug preparations using a cholesterol as an internal standard was investigated. They were saponified with 20% methanolic KOH solution. Phytosterols in the reaction mixture were extracted with diethyl ether and separated on silica gel TLC plate with n-hexane-diethyl ether(40:60) as the solvent and then were scraped off. They were separated by reversed phase high perfomance liquid chromatography on Inertsil ODS-2 column with detection at 205nm. Cholesterol and ${\beta}$-sitosterol were resolved from interferences by adjusting the acetonitrile content in the MeOH-tetrahydrofuran-$H_2O$ eluent. The detection limit of ${\beta$-sitosterol was 0.43${\mu}$g.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.183-192
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• 2014

For the structure determination of D-(+)-sucrose, which consists of ${\alpha}$-D-(+)-glucose and ${\beta}$-D-(+)-fructose, it was acetylated with acetic anhydride and triethyl amine, pyridine, zinc chloride, and sodium acetate as catalysts. The acetylated D-(+)-sucrose was acid-hydrolyzed using sulfuric acid and sodium chloride in methanolic solution. The structures of the reaction products were determined by $^1H$-NMR and $^{13}C$-NMR spectra. The yield of the acetylation indicated the high value in zinc chloride as 70% in zinc chloride catalyst. The acid-hydrolyzed product of the acetylated D-(+)-sucrose, 2,3,4,6,1',3',4',6'-octa-O-acetyl-D-(+)-sucrose, gave 2,3,4,6-tetra-O-acetyl-${\beta}$-D-(+)-glucose and it suggests that the acetylated D-(+)-sucrose was rearranged through the formation of oxonium ion by mutarotation in the 2,3,4,6-tetra-O-acetyl-${\alpha}$-D-(+)-glucose moiety and through the ring opening in the 1',3',4',6'-tetra-O-acetyl-${\beta}$-D-(+)-fructose moiety.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.206-213
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• 2007

Recently estimating the uncertainty of an analytical result has become an essential part of quantitative analysis. This study describes the uncertainty of the measurement for the determination of methamphetamine and its major metabolite amphetamine in human hair, The method consists of washing, drying, weighing, incubation and extraction with methanolic HCI solution, clean-up, trifluoroacetyl derivatization, and qualification/quantification of residues by gas chromatography/mass spectrometry (GC/MS). Traceability of measurement was established through traceable standards and calibrated volumetric equipment and measuring instruments. Measurement uncertainty associated with each analyte in real samples was estimated using quality control (QC) data. The main source of combined standard uncertainty comprised two components, which are uncertainties associated with calibration linearity and variations in QC, while those associated with preparation of analytical standards and sample weighing were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method ranged for individual analytes from 4.99 to5.03%.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.990-997
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• 2006

Sarcococca saligna is a shrub that is traditionally used for its medicinal properties in Pakistan. In this study we report the cardio-suppressant, vasodilator and tracheal relaxant activities of the aqueous-methanolic extract (Ss.Cr) of the plant. Ss.Cr, that tested positive for the presence of saponins, flavonoids, tannins, phenols, and alkaloids, exhibited a dose-dependent (0.3-5 mg/mL) negative inotropic and chronotropic effect on the isolated guinea-pig atrium which was resistant to atropine ($1\;{\mu}M$) and aminophylline ($10\;{\mu}M$) pretreatment. In rabbit thoracic aorta, Ss.Cr dose-dependently (0.1-3 mg/mL) relaxed the high $K^{+}$ (80 mM) and phenylephrine ($PE,\;1\;{\mu}M$)-induced contractions, indicating a possible $Ca^{++}$ channel blocking (CCB) effect. When tested against PE ($1\;{\mu}M$) control peaks in normal $Ca^{++}\;and\;Ca^{++}$-free Kreb's solution, Ss.Cr exhibited dose-dependent (0.1-3 mg/mL) inhibition, being more potent in relaxing the PE responses in $Ca^{++}$-free Kreb's solution, thus indicating specific blockade of $Ca^{++}$ release from the intracellular stores. Ss.Cr also relaxed the agonist-induced contractions in: a) rat aorta irrespective of the presence of endothelium or nitric oxide synthase inhibitor L-NAME and b) rabbit and guinea-pig tracheal strips. The data shows that Ss.Cr possesses possible $Ca^{++}$ channel blocking activity which might be responsible for its observed cardio-suppressant, vasodilator and tracheal relaxant effects though more tests are required to confirm this $Ca^{++}$ channel blocking effect.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.160-165
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• 1981

Radical copolymerization of the complexed 2-vinylpyridine with vinyl acetate and divinylbenzene initiated by azobisisobutyronitrile was carried out in N, N-dimethylformamide in presence of barium chloride at $98{\circ}C$. In the preparation of 2-vinylpyridine-vinylacetate-divinylbenzene terpolymer, the optimum reaction conditions were studied by means of various temperatures and times. 2-vinylpyridine-vinylalcohol-divinybenzene resin was prepared by transesterificating 2-vinylpyridine-vinylacetate-divinylbenzene terpolymer with a 1% methanolic sodium hydroxide solution. 2-Vinylpyridine-vinylphosphate-divinyldenzene was prepared by phosphorylating 2-vinylpyridine-vinylalcohol-divinylbenzene resin with phosphoric acid and urea. The compositions of each synthetic resin were identified by means of infrared absorption spectroscopy. The ion exchange capacities of each 2-vinylpyridine-vinylalcohol-divinylbenzene and 2-vinylpyridine-vinylphosphate-divinylbenzene terpolymer was 3.69 meq/g and 5.38 meq/g.

• Analytical Science and Technology
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• v.20 no.2
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• pp.115-123
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• 2007

The heterocyclic amines (HAs) are a family of mutagenic/carcinogenic chemicals formed from the cooking of muscle meats such as beef, meat, fowl, and fish. A major draw back in the analysis of HAs from foods is their very low level of concentration (ng/g) and a number of matrix interferences in samples. Solid-phase extraction (SPE) is one of the procedures widely used for the extraction and purification of HAs in food samples. In this study, several SPE procedures of HAs determination were performed. Recoveries of the HAs were obtained from comparing a matrix such as a standard methanolic solution and pre-cooked meat extracts. Recovery values were ranging between 25.3 and 93.0 % at a concentration of 25.0 ng/g. HAs were determined with high sensitivity by micro-HPLC (${\mu}$-HPLC) analysis with electrospray ionization mass spectrometry (ESI-MS). Another developed method, which is freezing filtration method, shows better extraction recoveries and good precisions. The established method will be applicable to monitoring of heterocyclic amines from the cooked meat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.129-136
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• 2024

Lactic acid bacteria (LAB) growth in processed meat products produces slime. In this study, 10 different biofilm-forming LAB, including Leuconostoc mesenteroides, Lacticaseibacillus paracasei, Levilactobacillus brevis, Lactiplantibacillus plantarum, Leuconostoc citreum, Weissella viridescens, and Latilactobacillus sakei, were isolated from various meat products and identified based on 16S rRNA gene analysis. To inhibit biofilm formation by LABs, Eisenia bicycles methanolic extract (EB) and ethyl acetate soluble fraction (EA) were used as antibacterial and antibiofilm agents, respectively. Furthermore, EA and EB were employed to synthesize gold nanoparticles (AuNPs) such as EB-AuNPs and EA-AuNPs, which could serve as antibiofilm agents against the isolated LAB. These findings demonstrate that EA, EB-AuNPs, and EA-AuNPs exhibit significant antibacterial activity against the isolated LAB. Furthermore, EB-AuNPs reduced L. citreum biofilm production, whereas EA-AuNPs inhibited L. mesenteroides and L. brevis biofilm formation. The current results suggest that EB-AuNPs and EA-AuNPs can be used as nanomaterials to inhibit LAB that form biofilms on meat products.

• Applied Biological Chemistry
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• v.16 no.3
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• pp.146-165
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• 1973

Crop damages caused by sulfur dioxide poisoning were studied with respect to physiology of lesion, yield loss and prevention measures. The results are summarized as follows; 1. On the physiology of injury: The sulfur dioxide gas did no: affect the pH and $E_h$ values of the tested leaf juice of plants. Peroxidase activity was inhibited just after sulfur dioxide treatment but gradually recovered to normal after 10 hours. Methanolic chlorophyll solution was instantaneously and irreversibly bleached by the addition of sulfur dioxide gas with no evidence of pheophytin formation. It seems that chlorophyll forms colourless addition product or is reduced to colourless form with either sulfur dioxide gas or sulfurous acid. Chlorophyll in the chloroplast was also bleached by the sulfur dioxide treatment, as in the case of methanolic solution of chlorophyll, except that the rate of bleaching was rather slow, requiring 1-2 hours. It appears that the most inflicting cause of sulfur dioxide gas to plants may be the destruction of chlorophyll by the poisoning gas. 2. On the effects to crop yield: The crop yield losses were proportional to the concentration of inflicting sulfur dioxide gas. The order of tolerence of the crops to the sulfur dioxide gas was as follows - chinese cabbage being the most susceptible; wheat, paddy rice, barley, soybean, welsh onion, radish and chinese cabbage. The crucifer crops were generally found more susceptible than other crops studied. With respect to the growing stages of crops exposed to sulfur dioxide gas, it was found that the flowering stage was the most susceptible fellowed by panicle forming, milky and tillering in the decreasing order of susceptibility. 3. On the preventive measures of yield losses: Soil applications of potassium, wollastonite, lime or spray of lime water were effective to prevent yield losses from sulfur dioxide fumigation of paddy rice, barley, and soybeans. The most responsive treatment was lime water spray for all crops tested. In case of sulfur dioxide fumigated paddy rice, the lime water spray also increased carbon assimilation.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.174-186
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• 2007

Amphora coffeaeformis and Achnanthes longipes are commonly found as dominant benthic microalgae in Jeju coastal water throughout the year. In order to investigate pharmaceutical uses of these diatoms, each single species was isolated with micropipette under phase contrast microscope and subcultured with synthetic seawater media which was enriched with F/2 media, trace metal solution and $Na_2SiO_3$). Growth characteristics of these species were also determined with different combination of salinity, nutrients concentration and temperature. Thereafter, mass culture of each species was done based on the maximum growth condition. Biomass was collected after two weeks of mass culture and freeze dried for antioxidant study. The antioxidant properties of different fractions (n-hexane, chloroform and ethylacetate) obtained by solvent fractionation of 80% methanolic extract of two microalgae were investigated for free radical, reactive oxygen species scavenging (Super oxide, Hydrogen peroxide, Hydroxyl radical and Nitric oxide), metal chelating and lipid peroxidation inhibition activities. All fractions of A. longipes showed higher $DPPH^{\cdot}$ (free radical) scavenging activities (n-hexane: 89.0%, Chloroform: 76.0%, Ethylacetate: 66.0%, Methanol: 90.6% and aqueous residue: 63.0%). N-hexane fraction of A. longipes showed significantly higher activity (49.0%) on nitric-oxide. Ethylacetate fraction of A. longipes and aqueous residue of A. coffeaeformis exhibited 64.0% and 75.6% metal chelating activity which was higher than commercial antioxidants (${\alpha}$-tocopherol: 18.0% and BHT: 16.0%). The n-hexane fraction of A. coffeaeformis had 67.5% activity on $DPPH^{\cdot}$. Chloroform and n-hexane fractions of A. coffeaeformis exhibited 46.2% and 47.6% $H_2O_2$ scavenging effects which were closely similar to commercial antioxidants (${\alpha}$-tocopherol: 49.2% and BHT: 58.6%). Chloroform and ethylacetate fractions of A. longipes and fraction of n-hexane and chloroform of A. coffeaeformis showed better lipid peroxidation activities than ${\alpha}$-tocopherol. These data suggest that both organic and aqueous fractions have good antioxidative compounds with different antioxidant properties.