• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.89-93
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• 2014

We aim to develop a simple method for simultaneous and quantitative determination of benzoic acid, caffeic acid and chlorogenic acid in seeds of Eriobotrya japonica. In addition, antibacterial effect of these three phenolic acids was examined. A basic method is performed on the high performance liquid chromatography system coupled to an UV-detector (230 nm) and reverse phase C-18 column ($4.6{\times}150mm$, $5{\mu}m$). Each phenolic acid was confirmed via liquid chromatography-mass spectrometry (MS)/MS system under the multiple-reaction monitoring with negative-ion electrospray ionization (ESI(-)) mode. It is demonstrated that the method was could be applied to samples for an analytical study of the phenolic acids. On the other hand, three phenolic acids in seeds of E. japonica exhibited antibacterial effect against several pathogenic bacteria. Of these, benzoic acid was found to have stronger antibacterial effect.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.279.2-280
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• 2003

A simple and accurate reverse-phase high performance liquid chromatography (HPLC) coupled with photodiode array was developed for the determination of dextromethorphan(DM) and its metabolite dextrorphan(DX) in human urine. Chromatographic separation was accomplished on a cyano analytical column at 220 nm using a mobile phase containing 25 mM triethylammonium phosphate buffer(PH 3.0) in a 0-70％ ACN gradient and triazolam(TZ) was used as internal standard(I.S). (omitted)

• Korean Journal of Plant Resources
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• v.20 no.3
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• pp.263-266
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• 2007

High performance liquid chromatography (HPLC) was used for the analysis of chiisanoside in each stem and root of Acanthopanax senticosus collected from South Korea, North Korea, China and Russia. A reverse-phase system using a gradient of H$_{2}$O and acetonitrile as the mobile phase was developed and detection was at 210nm. The analysis was successfully carried out within 30 min. Chiisanoside was measured in the stem and root of A. senticosus collected from various countries.

• Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.84-87
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• 2010

A peptide that inhibits HIV-1 protease was isolated from a hydrolysate of oyster (Crassostrea gigas) proteins digested with thermolysin. The peptide was using membrane filtration, gel permeation chromatography, ion exchange chromatography, and reverse-phase high performance liquid chromatography. Amino acid sequence of the peptide was determined to be Val-Phe-Glu-Leu. Chemically synthesized Val-Phe-Glu-Leu showed an $IC_{50}$ value of 106 ${\mu}M$.

• Applied Biological Chemistry
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• v.41 no.8
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• pp.595-599
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• 1998

An analytical method was developed to determine tricyclazole residues in rice grain, straw, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Tricyclazole was extracted with methanol from moist rice grain, straw, and soil samples. n-Hexane washing was employed to remove nonpolar co-extractives during liquid-liquid partition. Tricyclazole was then extracted with dichloromethane from alkaline aqueous phase, while acidic interferences remained in the phase. Dichloromethane extract was further purified by silica gel column chromatography prior to HPLC determination. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate the tricyclazole residue in sample extracts monitored at ${\lambda}_{max}$ 225nm. Recoveries from fortified samples averaged $95.5{\pm}3.0%\;(n=6),\;87.5{\pm}20.%\;(n=6),\;and\;84.3{\pm}2.8%$ (n=12) for rice grain, straw, and soil, respectively. Detection limit of the method was 0.02 mg/kg for rice grain and soil samples while 0.05 mg/kg for rice straw samples. The proposed method was reproducible and sensitive enough to evaluate the safety of tricyclazole residues in rice grain, straw, and soil.

• BMB Reports
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• v.32 no.6
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• pp.521-528
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• 1999

The folding of recombinant hepatitis B virus X-protein (rHBx) solubilized from Escherichia coli inclusion bodies was investigated. By sequential dialysis of urea, rHBx was folded into its native structure, which was demonstrated by the efficacy of its transcriptional activation of the adenovirus major late promoter (MLP), fluorescence spectroscopy, and circular dichroism (CD) analysis. The decrease in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of rHBx to refold in lower concentrations of urea, yielding the active protein. Equilibrium and kinetic studies of the refolding of rHBx were carried out by tryptophan fluorescence measurements. From the biphasic nature of the fluorescence curves, the existence of stable intermediate states in the renaturation process was inferred. Reverse phase-high performance liquid chromatography (RP-HPLC) analysis further demonstrated the existence of these intermediates and their apparent compactness.

• Advances in Traditional Medicine
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• v.4 no.4
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• pp.267-273
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• 2004

Oxidative stress is associated with many kinds of chronic diseases. Antioxidants such as polyphenols are compounds that protect cells against the damaging effects of reactive oxygen species. Grape seeds are considered good resources of polyphenols, and grape seed extracts have a very strong antioxidant effect. In the present study, we established a simple gradient reverse-phase high performance liquid chromatography method to determine polyphenol content from three different grape seed resources. An ODS (2), $150\;{\times}\;3.2\;mm$ column has been employed, and six polyphenols have been determined: gallic acid, protochatechuic acid, (+)-catechin, (-)-epicatechin, procyanidin B2, and epicatechin gallate. Catechin and epicatechin were the main polyphenol compounds in all three extracts. The amount of procyanidin B2 was higher in Extract 1 (from a company of China), while Extract 2 (extracted in our lab) and Extract 3 (from a company of USA) contained higher proportions of epicatechin gallate. For the total polyphenol content, Extract 1 was much higher than that of Extract 2 and 3. The results suggest that the dietary dose of grape seed extracts from different resources should be adjusted according to polyphenol content.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.251-257
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• 2004

Analytical methods were developed to determine cyclosulfamuron residues in soil, water, rice grain and straw using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. In these methods, cyclosulfamuron was extracted with aqueous $Na_2HPO_4$/acetone and acetone/methanol mixture from soil and rice samples respectively. Liquid-liquid partition coupled with ion-associated technique, Florisil column chromatography, and solid-phase extraction (SPE) were used to separate cyclosulfamuron from interfering co-extractives prior to HPLC analysis. For water sample, the residue was enriched in $C_{18}$-SPE cartridge, cleaned up in situ, and directly subjected to HPLC. Reverse-phase HPLC under ion-suppression was successfully applied to determine cyclo-sulfamuron in sample extracts with the detection at its ${\lambda}_{max}$ (254 nm). Recoveries from fortified samples averaged $87.8{\pm}7.1%$ (n=12), $97.3{\pm}7.2%$ (n=12), $90.8{\pm}6.6%$ (n=6), and $78.5{\pm}6.7%$ (n=6) for soil, water, rice grain and straw, respectively. Detection limits of the methods were 0.004 mg/kg, 0.001 mg/L, 0.01 mg/kg and 0.02 mg/kg for soil, water, rice grain and straw samples, respectively.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.556-561
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• 2010

Tomato fruits(Lycoperisicon esculentum) synthesize the glycoalkaloids dehydrotomatine and ${\alpha}$-tomatine, possibly as defense against bacteria, fungi and insects. We developed a new effective method to prepare and purify dehydrotomatine and ${\alpha}$-tomatine that exists in tomato fruits using alumina column chromatography and high performance liquid chromatography (HPLC). The tomato glycoalkaloids(TGA) in tomato was extracted with 2% acetic acid, and then precipitated with ammonium hydroxide(pH=10.5). The dry precipitate substance was applied on alumina column, and then fractionated with water saturated n-butylalcohol. The TGA(Fr. No. 26~36) were collected and dried under reduced pressure. The TGA was performed on a reverse phase HPLC(Inertsil ODS-2, $5\;{\mu}m$), eluted with acetonitrile/20mM $KH_2PO_4$(24:76, v/v) at 208 nm. Two peaks were detected on HPLC, and individual peak was collected by repeating HPLC. Furthermore, to confirm the identity dehydrotomatine and ${\alpha}$-tomatine, each peak isolated was hydrolyzed with 1N HCl into sugar and aglycone tomatidine. The sugars were converted to trimethylsilyl ester derivatives. The nature and molar ratios of sugars were identified by gas-liquid chromatography(GLC) and the aglycone by high-performance liquid chromatography(HPLC). The first peak (Rt=17.5 min) eluted from HPLC was identified as dehydrotomatine, and second peak(Rt=21.0 min) was as ${\alpha}$-tomatine. This technique has been used effectively to prepare and isolate dehydrotomatine and ${\alpha}$-tomatine from tomato fruits.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.377-381
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• 2015

The content analysis of 6-gingerol, which is an active compound, in Zingiber spp. (Z. officinale and Z. mioga) and their commercial foods (ginger teas and powders) was conducted using high-performance liquid chromatography. A reverse phase system was used, with a gradient solvent system of water and acetonitrile. The 6-gingerol content was highest in the methanol extract of Z. officinale root (17.09 mg/g extract) and ginger powder B (15.92 mg/g extract). The results demonstrated that this method was simple and reliable for the quality control of Zingiber commercial foods.