• Korean Journal of Veterinary Research
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• v.36 no.3
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• pp.541-550
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• 1996

Tetracycline antibiotics have been widely used not only therapeutics but feed additives. There are many methods for the isolation and determination of tetracycline antibiotics in animal muscle tissue. But those methods take much time and labor, so it is difficult to analyse many samples simultaneously. A rapid isolation method and liquid chromatographic determination of tetracycline antibiotics in animal muscle tissue (bovine, porcine, chicken) is presented. Blank control and tetracyclines fortified samples (0.5g) were blended with $C_{18}$ containing 0.05g each of oxalic acid and disodium ethylenediaminetetraacetate. After homogenize, homogenate was transferred to glass column made from 10ml glass syringe and compressed to 4~4.5ml volume. A column made from the $C_{18}$/meat matrix was washed with hexane (8ml) and dichloromethane (8ml, if needed), following which the tetracyclines were eluted,vith methanol or 0.01M methanolic oxalic acid (8ml). The eluates containing tetracyclines analytes were free from interfering compounds when analysed by HPLC with UV detection (photodiode array at 360nm). Standard curve for each tetracycline showed a linear response at the range of $0.05{\sim}1.0{\mu}g/ml$ and tetracycline antibiotics were eluted within 4ml of eluted volume. All tetracycline antibiotics except tetracycline were stable during the concentration process at $40^{\circ}C$ and time required for concentration was 3~4 hours. Fortified samples containing oxalic aicd and EDTA represented more good recoveries than those of not-contained sample. Recoveries were 91.8~110.1% (oxytetracycline; OTC), 57.7~79.5% (tetracycline; TC), 78.1~88.6% (chlortetracyclines; CTC) and 88.4~100.6% (doxycycline; DC) in pork tissue, 101.1~126.8% (OTC), 66.4~75.4% (TC), 79.2~88.1% (CTC) and 69.3~86.7% (DC) in beef tissue, and 90.8~95.6% (OTC), 66.2~84.4% (TC), 75.7~77.2% (CTC) and 55.6~80.7% (DC) in chicken muscle tissue. The detection limits validated in muscle tissue by this method were $0.05{\mu}g/g$ for OTC and TC, and $0.1{\mu}g/g$ for CTC and DC.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.535-539
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• 2007

The fructus of Crataegus pinnatifida Bunge has been used as medicinal and food source in worldwide. In this study, a strong direct thrombin inhibition and antithrombosis activity were identified from the methanol extract of C. pinnatifida Bunge fructus. The solvent fractionation of fructus extract using hexane, ethylacetate, butanol revealed that the butanol fraction has a prominent antithrombin activity. Thrombin time(blood-clot formation time) and activated partial thromboplastin time(aPTT) extended to 835% and 315% by addition of the butanol fraction at concentration of 1.25 mg/mL, whereas thrombin time extended to 287% by addition of aspirin at concentration of 1,25 mg/mL. The butanol fraction showed anthrone-positive and weak ninhydrine-postive reaction. The thrombin inhibitory activity was not related to previously reported flavonoids or polyphenols. The activity was maintained against acid treatment(0.5 N HCl for 120 min), but rapidly lost by heat-treatment($100^{\circ}C$ for 30 min). Our results suggested that fructus of C. pinnatifida Bunge with non-heat treatment process could be developed as a natural source of antithrombosis.

• Journal of Food Hygiene and Safety
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• v.23 no.4
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• pp.324-329
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• 2008

An analytical method for the simultaneous determination of nine quinolones (QNs) namely, marbofloxacin, norfloxacin(IS), ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in flatfish and egg was developed and validated using liquid chromatography with fluorescence detection (LC-FD). The samples were extracted using a traditional liquid-liquid extraction process; deproteinization was accomplished by the addition of trichloroacetic acid and acetonitrile (ACN), and defatting was performed with hexane. Chromatographic separation was achieved on a reverse phase C8 column with gradient elution using a mobile phase of 200 mM ammonium acetate buffer (pH 4.5) and ACN. The proposed method was validated according to the CODEX guideline. Mean recoveries of QNs from flatfish and egg were 89.6-106.5% with relative standard deviations (RSDs) below 15% at three different concentrations of 50, 100 and $500{\mu}g/kg$. Linearity was obtained with a correlation coefficient ($r^2$) of 0.9989-1.0000. The LOD for the investigated QNs was $1-16{\mu}g/kg$ depending on flatfish and egg. The present method can be applied simultaneously to determine QNs in muscle of flatfish and egg.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.775-779
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• 2002

Barley brans, divided into fractions I $(pearlers\;1{\sim}4)$, II $(pearlers\;5{\sim}20)$, and III $(pearlers \;21{\sim}24)$, germ, and broken kernels were collected as pearling by-products produced by an industrial process consisting of 24 consecutive barley pearlers. The pearling by-products were extracted with 75% ethanol, and polyphenol extracts were separated using Sepabeads SP-850 resin. Total polyphenol content was the highest (43.68%) in the polyphenol extract separated from fraction I. Polyphenol compounds analyzed by HPLC were tentatively identified as proanthocyanins and prodelphinidin polymers, which were known to have antioxidative and antimutagenic activities. Antioxidative abilities were estimated to be in the following order: fraction I>germ>fraction II>fraction III. At 0.01% polyphenol extract, angiotensin I-converting enzyme inhibitory activity was the highest in the germ fraction (40.04%). Nitrite-scavenging activity was over 70% in all fractions. Superoxide dismutase-like activity was in the range of $64{\sim}78%$ in fractions I and II.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.601-608
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• 1997

In order to search for the way to utilize rice hull as a renewable resource, the inhibition on ${\alpha}-glucosidase$ and the fractionation of rice hull extract was investigated. An ethanol extract of rice hull from Japonica-type rice seeds exhibited 30% inhibitory activity on rat intestinal brush border ${\alpha}-glucosidase$ (1.4 mU/mL) in vitro at the concentration of 0.8 mg/mL using 6 mM p-nitrophenyl ${\alpha}-D-glucopyranoside$ as a substrate $(IC_{50}\;162\;mg/mL)$. Among the fractions obtained by partitioning the ethanol extract successively with solvents, the ethyl acetate fraction at the concentration of 0.8 mg/mL was found to exhibit the most potent inhibitory activity i.e. 65% inhibition of ${\alpha}-glucosidase\;(IC_{50}\;0.14\;mg/mL)$. Silica gel column chromatography of the ethyl acetate fraction exhibited slightly higher (90%) inhibitory activity, and its subsequent fractionation by Sephadex LH-20 column chromatography did not improve inhibitory activity. Considering the inhibitory activity and yield, the ethyl acetate fraction obtained by the solvent-partitioning process would be a candidate for the hypoglycemic food if it has in vivo effectiveness.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.359-363
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• 2009

This study was performed to establish a rapid and simple analytical method for niacin (nicotinic acid and nicotinamide) using HPLC. A pretreatment method for the extraction and clean-up of niacin in infant formula sample and an instrumental condition for HPLC were optimized. Niacin was extracted by 5 mM hexanesulfonate with ultrasonication for 30 min. For the clean-up of the sample, the extract was applied to a HLB cartridge, and then niacin was eluted from the cartridge using 5 mL of 80% methanol after washing with 5 mL of n-hexane. The total recoveries were $83{\sim}104%$ and relative standard deviation were in the range of $1.5{\sim}3.5%$ during the extraction and clean-up process. Niacin was determined by gradient elution with sodium hexanesulfonate/methanol buffer as a mobile phase and a photodiode array detector (260 nm). It showed a high linearity between the content of niacin and the peak area ($r^2$=1.000) in the range of $0.02{\sim}10.0$ mg/L of nicotinic acid and nicotinamide. The detection limit was 0.02 mg/L (0.2 mg/kg in the sample). The method was successfully applied for the determination of niacin in infant formula. Total niacin contents were in the range of $53.5{\sim}140.3$ mg/kg.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.3
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• pp.91-95
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• 2020

In this study, we report a hydrothermal synthesis in which BaTiO₃ nanoparticles (NPs) with enhanced size uniformity and dispersibility are synthesized by increased time and temperature, increasing nucleation and diffusion rates. The formation process of an uniform size of 20 nm BaTiO₃ NPs, which has not been extensively researched, was optimized through hydrothermal synthesis at 180℃. Simultaneous increase in the nucleation rate of TiO₂ and diffusion length of Ba²⁺ ions, resulting from a higher temperature, allowed for the synthesis of BaTiO₃ NPs (20 nm) with significantly enhanced size-uniformity. The size and crystallinity of BaTiO₃ NPs which exhibit excellent dispersibility in hexane solvent were investigated using transmission electron microscopy and X-ray diffraction. The results presented herein provide insights into improving the size uniformity and dispersibility of BaTiO₃ NPs by hydrothermal synthesis for applications to variety of electronic devices.

• KSBB Journal
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• v.21 no.3
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• pp.224-229
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• 2006

FEMLAB is a powerful interactive environment for modeling, solving all kinds of scientific and engineering problems based on partial differential equations(PDEs). Separation process of chiral compound in HPLC columns was simulated by FEMLAB. To study change of elution profile with isotherm models, non-competitive and competitive Langmuir adsorption isotherm were adopted. Separated material was (R, S)-ibuprofen [(R, S)-2-(4-isobutyl phenyl) propionic acid], an anti-inflammatory agent, which retain the pharmacological activity in the (S)-(+)-enantiomer. Sample concentrations were changed from 0.5 mg/ml to 2.0 mg/ml at a flow rate of 1 ml/min and flow rate varied from 1 ml/min to 3 ml/min at an ibuprofen concentration of 2.0 mg/ml and $20{\mu}l$ of injection volume. Simulated results were well fitted with experimental data.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.90-96
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• 2013

The anti-obesity effect of ethanol xtract and their fractions from Rumex Crispus L. on the differentiation of 3T3-L1 pre-adipocytes to adipocytes was investigated by suppressing adipocyte differentiation and lipid accumulation with Oil red O assay, western blot and real-time PCR analysis. Ethyl acetate fraction of Rumex crispus L. significantly inhibited adipocyte differentiation when treated during the adipocyte differentiation process, as assessed by measuring fat accumulation using Oil red O staining. In inducing differentiation of 3T3-L1 preadipocytes in the presence of an adipogenic cocktail, isobutylmethylxanthine (IBMX), dexamethasone- and insulin-along with ethyl acetate fraction residue processing treatment significantly decreased protein expression of obesity-related proteins, such as peroxisome-proliferators-activated-receptor-${\gamma}$ ($PPAR{\gamma}$) and CCAAT enhancer-binding-proteins ${\alpha}$ ($C/EBP{\alpha}$). These results indicate that ethyl acetate fraction of Rumex crispus L. is the most effective candidate for preventing obesity. However further studies will be needed to identify the active compounds that confer the anti-obesity activity of ethyl acetate fraction from Rumex crispus L.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.118-123
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• 2018

The objective of this study was to develop a sensitive method for the identification and determination of nitrovin in fishery products by using a solid-phase extraction (SPE), as performed with a liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with a mixture of acetonitrile and water, and were then defatted with acetonitrile saturated hexane, after which further clean-up was accomplished with SPE on the hydrophilic-lipophilic balance (HLB) cartridges. The analytes were subsequently ionized in the positive mode of an electrospray ionization (ESI), and where thereby detected in a process of multiple reaction monitoring (MRM). The linearity (expressed as correlation coefficients) of the matrix calibration curves was > 0.985. The limit of the quantification for the nitrovin was measured at 0.001 mg/kg. The accuracy (expressed as average recovery) was noted between 72.1 and 122%. The precision (expressed as coefficient variation) was noted from 2.9 to 16.9%. According to the CODEX CAC/GL-71 guideline accuracy, precision, linearity, and limit of detection were determined in three matrices (which were flatfish, eel and shrimp). The proposed method was suitable for analyzing the associated nitrovin residues. This application and result can also be a factor to contribute to the non-detection drugs management in fishery products.