• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.370-374
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• 2007

An analytical method for the simultaneous determination of four tetracycline (oxytetracycline, tetracycline, chlortetracycline, doxycycline) in egg samples was developed and validated using liquid chromatography with ultraviolet detection. Egg samples were extracted by the liquid-liquid extraction based on acetonitrile. The chromatographic separation was achieved on a reverse phase C8 column with gradient elution using a mobile phase of 20 mM oxalic acid (pH 1.5)/acetonitrile. The procedure was validated according to the Food Drugs Administration guideline determining accuracy, precision, and limit of detection. Mean recovery of tetracyclines from spiked egg samples (50, 100, 200, 400, and $800{\mu}g/kg$) were 78.8-109.3%. Linearity in concentration range of $50-800{\mu}g/kg$ was obtained with the correlation coefficient $(r^2)$ of 0.994-0.999. The intra- and inter-day precision (relative standard deviation; RSD) was between 0.3-12.8 and 0.2-11.7%, respectively. Limit of detection (LOD) and limit of quantification (LOQ) for the investigated tetracyclines were 30 and $50{\mu}g/kg$ depending on egg samples, respectively. This method was reliable, sensitive, economical and suitable for routine monitoring of tetracycline residues in dairy egg.

• 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.

• Analytical Science and Technology
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• v.6 no.1
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• pp.9-19
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• 1993

Fatty acid salts derived from soap can be transferred into a typical derivative with p-bromophenacyl bromide using crown ether, a catalizer by the solid-liquid phase transfer reaction in nonpolar, aprotic solvents and separated by the reverse phase high performance liquid Chromatography (RP-HPLC) and determined using UV detector. The minimal limit of detection was defined at approximately 10~50ng in accordance with the chain length. The derivatization reaction in the presence of EDTA can be applied mot only to the calcium salts but also to the other various metal salts. The recoveries of fatty acid derivatizations in the absence and presence of the midium containing the yeast extract were obtained $95.4{\pm}1.2$, and $85.2{\pm}2.4%$ respectively. The analytical method would be applicable to determine the biodegradation of fatty acid salts in nature as well as in artificial condition such as shaker flask-medium method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.1-6
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• 1981

In this study, sesame oil was chosen as the experimental sample and analysed for its triglyceride composition by high-performance liquid chromatography(HPLC) in combination with gas liquid chromatography(GLC). The triglycerides were separated from sesame oil by liquid chromatographies on Bio-Beads SX-2 and on Sephadex LH-20, and fractionated into five groups on the basis of their partition numbers by reverse phase HPLC on a column packed with $\mu-Bondapak$ C18 using methanol-chloroform mix-ture as a solvent. Each of these collected fractions gave one to three peaks in the GLC chromatograms according to the acyl carbon number of the triglyceride, and fatty acid composition of the triglyceride was also analysed by GLC. From the results, it was found that the sesame oil consists with twenty one kinds of triglyceri-des, and the major triglycerides of sesame oil are those of $(2\;{\times}\;C18:1,\;C18:2\;;\;17.1\%),\;(C18:1,\;2{\times}C18:2\;;\;17.0\%),$ $(3\;{\times}\;C18:2\;;\;17.0\%),\;(3\;{\times}\;C18:1\;;\;10.9\%),$ $(3\;{\times}\;C18:2\;;\;9.6\%),\;(C16:0,\;C18:1,C18:2\;;\;7.9\%),$ $(C16:0,\;2\;{\times}\;C18:1\;;\;7.4\%),\;(C16:0,\;2\;{\times}\;C18:2\;;\;6.8\%),$ $(C18:0,\;C18:1,\;C18:2\;;\;3.1\%),\;(2\;{\times}\;C18:0,\;C18:2\;;\;1.5\%)$ $(C18:0,\;2\;{\times}\;C18:1\;;\;1.4\%),\;(C16:0,\;C18:0,\;C18:1\;;\;1.3\%),$ $(2\;{\times}\;C16:0,\;C18:1\;;\;1.2\%),\;and\;(C16:0,C18:0,\;C18:2\;;\;1.0\%)$.

• Journal of Life Science
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• v.19 no.7
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• pp.994-1002
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• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.

• Food Science and Preservation
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• v.17 no.3
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• pp.376-383
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• 2010

Including crude fat content, triacylglycerol species, tocopherols and phytosterols were analyzed in 8 kinds of nuts (sunflower seed, cashew nut, walnut, pistachio, pumpkin seed, ginkgo, hazel nut and pecan). The extracted crude fats showed 0.63~39.60 wt%, among which hazel nut showed the highest amount of fat content. Oleic acid (C18:1) was major fatty acids at sn-2 position in cashew nut, pistachio, hazel nut, and pecan while sunflower seed, walnut, and pumpkin seed showed linoleic acid (C18:2) as a major fatty acids at sn-2 position. Especially, ginkgo contained 10.72 wt% of vaccenic acid (C18:1-n7) at sn-2 position. The TAG species of 8 kinds of nuts were analyzed by reverse-phase HPLC, from which PN value ranged 40~52. Among the analyzed nuts, higher content of tocopherols were observed in ginkgo (48.57 mg/100 g), sunflower seed (38.35 mg/100 g), and pumpkin seed(31.43 mg/100 g). Total phytosterols were observed with the range of 88.60~947.20 mg/100 g.

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.392-398
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• 2002

Comparative analysis of paeoniflorin, albiflorin and phenolic compound contents as bioactive components of peony was performed by Reverse Phase-High Performance Liquid Chromatography (RPHPLC) using the four- year-old peony which were different plant parts and pretreatment, such as removing or unremoving the cork layer of peony root before drying. The contents of paeoniflorin, albiflorin, (+)-taxifolin $3-O-{\beta}-D-glucopyranoside$, (+)-catechin and (-)-epicatechin were the highest in rhizome part, but those of gallic acid and benzoic acid in the leaves were higher than other parts. The contents of albiflorin, gallic acid, benzoic acid and (-)-epicatechin in the cork layer were higher than in those of the core, but the contents of paeoniflorin, (+)-taxifolin $3-O-{\beta}-D-glucopyranoside$ and (+)-catechin in the core were higher than those in the cork layer. In general, the rhizome part of peony root has been used only propagation purpose, but this part contained high contents of bioactive component. Therefore, it is needed that medicinal application of rhizome part in peony root was firmly investigated. Also, In the use of peony root for medicinal purpose, the use of peony root with cork layer can be efficient way on the practical use of useful components and the reduction of labor for removing the cork layer.

• KSBB Journal
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• v.14 no.1
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• pp.9-16
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• 1999

Transforming growth factor $\beta$1(TGF-$\beta$1) has potentials to be used as a new therapeutic agent. However, studies with TGF-$\beta$ were hindered by its high cost. In this study, we developed an improved method to purify TGF-$\beta$1 from human platelets, for which four purification steps were used: platelet extraction, gel filtration, cation exchange chromatography, and reverse phase high performance liquid chromatography. After a final step of purification, a pure protein with a molecular weight of 25,000 corresponding to the commercially available TGF-$\beta$1 was obtained, which were confirmed by silver staining and Western blotting after SDS-polyacrylamide gel electrophoresis (SDS-PAGE). It was confirmed by the inhibitory effects of TGF-$\beta$1 on a mink lung epithelial cell line that the purified TGF-$\beta$1 had its biological activity, whose activity is slightly higher than that of the commercially available TGF-$\beta$1. About 3.7$\mug of the purified TGF-$\beta$1 was obtained from 10 units of concentrated human platelets, the final yield of which is about 21%.

• BMB Reports
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• v.38 no.1
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• pp.58-64
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• 2005

Myo-inositol monophosphate phosphatase (IMPP) is a key enzyme in the phosphoinositide cell-signaling system. This study found that incubating the IMPP from a porcine brain with pyridoxal-5'-phosphate (PLP) resulted in a time-dependent enzymatic inactivation. Spectral evidence showed that the inactivation proceeds via the formation of a Schiff's base with the amino groups of the enzyme. After the sodium borohydride reduction of the inactivated enzyme, it was observed that 1.8 mol phosphopyridoxyl residues per mole of the enzyme dimer were incorporated. The substrate, myo-inositol-1-phosphate, protected the enzyme against inactivation by PLP. After tryptic digestion of the enzyme modified with PLP, a radioactive peptide absorbing at 210 nm was isolated by reverse-phase HPLC. Amino acid sequencing of the peptide identified a portion of the PLP-binding site as being the region containing the sequence L-Q-V-S-Q-Q-E-D-I-T-X, where X indicates that phenylthiohydantoin amino acid could not be assigned. However, the result of amino acid composition of the peptide indicated that the missing residue could be designated as a phosphopyridoxyl lysine. This suggests that the catalytic function of IMPP is modulated by the binding of PLP to a specific lysyl residue at or near its substrate-binding site of the protein.

• Toxicological Research
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• v.23 no.2
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• pp.143-150
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• 2007

Although animal and epidemiological studies have suggested oxidative stress as an etiological factor in pathogenesis including cancer, inflammation, sepsis, fibrosis, cardiovascularlneurodegenerative diseases and aging-related disorders, conflicting results have been obtained in clinical trial with antioxidants. The reason for this discrepancy remains unknown but may be due, in part, to the lack of a validated assay system for evaluating antioxidant capacity. The antioxidant activity of a series of sugar alcohols against peroxyl radicals, hydroxyl radicals and peroxynitrites was determined by the total oxy-radical scavenging capacity (TOSC) assay and cell-based assay using H4IIE cells. Specific TOSC values calculated from the slope of the linear regression for erythritol, xylitol, sorbitol or mannitol against peroxyl radicals was $2.1{\pm}0.2,\;3.7{\pm}0.3,\;9.1{\pm}0.3$ or $8.7{\pm}1.1$ TOSC/mM, respectively. Specific TOSC values for erythritol, xylitol, sorbitol or mannitol against peroxynitrite was $1.9{\pm}0.3,\;3.9{\pm}0.4,\;7.8{\pm}0.7$ or $7.7{\pm}0.5$ TOSC/mM, respectively. These results suggest that oxy-radical scavenging capacity is dependent on the number of aliphatic hydroxyl group in sugar alcohols of monosaccharide. Tert-butylhydroperoxide (t-BHP)-induced cell toxicity determined by MTT assay was marginally attenuated by 10 mM erythritol, but completely inhibited by 10 mM xylitol, 2 mM sorbitol or 0.75 mM maltitol, a disaccharide alcohol. Oxidative stress markers, such as glutathione (GSH) and malondial-dehyde (MDA) levels, were measured in t-BHP-treated cells using HPLC equipped with a fluorescence detector and a reverse phase column. Erythritol did not change the levels of GSH and MDA in H411E cells treated with t-BHP. The t-BHP-induced changes in cellular GSH and MDA levels were ameliorated by 10 mM xylitol and completely blocked by 10 mM sorbitol and maltitol. These results indicate that sugar alcohols protect cells against oxidative stress via scavenging oxy-radical and suggest that TOSC assay in conjunction with cell-based assay is a valid method for evaluating antioxidant capacity of natural and synthetic chemicals.