• Journal of Environmental Health Sciences
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• v.40 no.2
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• pp.114-126
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• 2014

Objectives: We aimed to develop a measurement method of five metabolites of trichloroethylene (TCE) in a concurrent biological sample, e.g., trichloroacetic acid (TCA), dichloroacetic acid (DCA), S-(1,2-dichlorovinyl) glutathione (DCVG), S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NAcDCVC) and to validate the method before application to pharmacokinetic study. Methods: TCE metabolites were simultaneously analyzed using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) with as little as 50 ${\mu}L$ of serum and urine. DCA, TCA and NAcDCVC were extracted with diethyl ether, while DCVC and DCVG were extracted by solid phase extraction. This method was validated according to the guidelines for bioanalytical method validation of the Korean National Institute of Toxicological Research. Then, we determined the five metabolites in five strains of mice at 24 hr after exposure to 1 g TCE /kg body weight. Results: The limits of detection for the five metabolites in biological samples ranged from 0.001 to 0.076 nmol/mL, which is comparable to or better than those previously reported. Most calibration curves showed good linearity ($R^2=0.99$), and between-batch variation was less than 20% expressing acceptable robustness and reproducibility. Using this method, we found TCA and DCA were detected in all test mice at 24 hr after the oral administration while NAcDCVC and DCVC were detected in some strains, which showed strain-dependent metabolism of TCE. Conclusions: The present method could provide robust and accurate measurements of major key metabolites of TCE in biological media, which allowed concurrent analysis of TCE metabolism for limited amounts of biospecimens.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.672-675
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• 2005

Two anthocyanins were isolated from 1% HCl-20% methanol extracts of KG 97287 black common bean (Phaseolus vulgaris L.) using semipreparative, high-performance liquid chromatography (HPLC). The anthocyanins were identified using a combination of LC/ES-mass spectrometry (MS) and spectroscopic methods of UV-Vis, $^1H-$ and $^{13}C-$ nuclear magnetic resonance (NMR). The chemical structures of these two anthocyanins were elucidated as delphinidin 3-glucoside and petunidin 3-glucoside and their contents in KG 97287 black common bean seed coats were determined to be $2.614{\pm}0.11$ and $0.167{\pm}0.01\;mg/g$, respectively. These contents were lower than reported internationally and we recommend the introduction into Korea of high anthocyanin varieties of black common bean.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.123-127
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• 2007

Aristolochic acid (AA) included in the plants Aristolochiaceae have been well known to be nephrotoxic and carcinogenic inducer and to cause renal disease such as Chinese Herb Nephropathy (CHN). In this study, we used a high performance liquid chromatopaphy-mass spectrometry (HPLC-MS) under the positive ion detection mode for the quantitative change of aristolochic acid-I and-II (AA-I and AA-II) in Aristolochiaceae (Aristolochia contorta Bunge, Aristolochia debilis Sieb. et Zucc., Aristolochia fangchi Wu), some related plants (Cocculus trilobus De candolle, Inula helenium Linne, Saussurea lappa Clarke), and its prescriptions (防己茯笭湯, 定喘散) with or without processing. Here, the processing methods and prescriptions in oriental medicine were generally used to alleviate toxicity or alter property of herbal medicines. However, the concentrations of AA-I and AA-II were highly determined in processed material extracts rather than unprocessed those, not measured in some related plants. Also, the concentrations of AA-I and AA-II even at the prescriptions mixed the plants of Aristolochiaceae were detected to range from 0.73 to 2.53 ppm. Thus, the present results suggest that the content of AA-I and AA-II contained to plants of Aristolochiaceae was not reduced by the processing methods or prescriptions which can induce the physico-chemical change and pharmacological transformation in traditional herbal medicines.

• Journal of Life Science
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• v.21 no.3
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• pp.464-467
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• 2011

Quercetin is a major flavonoid present in onions, which acts as an antioxidant. Quercetin exists both as a free compound and conjugated with carbohydrates, primarily as glucosides in onion. Aged black onion was made through a 30 day aging process in which the onions were kept in an environment of $60^{\circ}C$ and high humidity (90% RH). Quercetin and quercetin glucosides were assayed in onion bulbs before and after the aging process, using high performance liquid chromatography-electrospray ion trap mass spectrometry (HPLC-ESI/MS/MS). Quercetin mono- and diglucosides were identified in fresh onion bulbs, whereas quercetin aglycone was the only form present in aged black onion bulbs. These findings indicate that the quercetin mono- and di-glucosides present in fresh onions undergo complete deglycosylation during the aging process. Such profiling will provide a rapid method that can be used to assess changes in the two major quercetin glycosides during the aging process of onion bulbs.

• Korean Journal of Pharmacognosy
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• v.43 no.1
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• pp.10-15
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• 2012

An accurate and sensitive analysis method was established for simultaneous determination of three bioactive compounds (glycyrrhizin, 6-gingerol and ginsenoside Rg3) in the Ejung Tang with high-performance liquid chromatography (HPLC)-photodiode array detection (DAD)-electrospray ionization (ESI)-Mass spectrometry (MS). The optimizing chromatographic separations a were acquired by an $C_{18}$ column ($5{\mu}m$, $4.6I.D{\times}250mm$, SHISHEDO) using gradient elution with water comprising 0.1% TFA(trifluoroacetic acid) and acetonitrile at a performing temperature of $35^{\circ}C$. Flow rate was 1.0 ml/min. A detection UV wavelength set at 205 nm and 250 nm. The three compounds were identified by electrospray ionization mass spectrometry. All calibration curves indicated great linear regression within test ranges ($R^2>0.9997$). The established method provided acceptable precision and accuracy. The relative standard deviations (RSDs) of intra-day and inter-day were less than 2.00% and 3.00%, respectively. The recoveries were found to range from 94.49 to 101.10% for the three compounds analyzed. These results showed that this method was effective and reliable for quality control of Eiung-Tang.

• Analytical Science and Technology
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• v.37 no.2
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• pp.98-113
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• 2024

The current investigation entails the characterization of five degradation products (DPs) formed under different stress conditions of loteprednol using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, this study developed a stable high-performance liquid chromatography (HPLC) method for evaluating loteprednol along with impurities. The method conditions were meticulously fine-tuned which involved the exploration of the appropriate solvent, pH, flow of the mobile phase, columns, and wavelength. The method conditions were carefully chosen to successfully resolve the impurities of loteprednol and were employed in subsequent validation procedures. The stability profile of loteprednol was exposed to stress degradation experiments conducted under five conditions, and DPs were structurally characterized by employing LC-MS/MS. The chromatographic resolution of loteprednol and its impurities along with DPs was effectively achieved using a Phenomenex Luna 250 mm C18 column using 0.1 % phosphoric acid, methanol, and acetonitrile in 45:25:30 (v/v) pumped isocratically at 0.8 mL/min with 243 nm wavelength. The method produces an accurate fit calibration curve in 50-300 ㎍/mL for loteprednol and LOQ (0.05 ㎍/mL) - 0.30 ㎍/mL for its impurities with acceptable precision, accuracy, and recovery. The stress-induced degradation study revealed the degradation of loteprednol under basic, acidic, and photolytic conditions, resulting in the formation of seven distinct DPs. The efficacy of this method was validated through LC-MS/MS, which allowed for the verification of the chemical structures of the newly generated DPs of loteprednol. This method was appropriate for assessing the impurities of loteprednol and can also be appropriate for structural and quantitative assessment of its degradation products.

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.277-282
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• 2008

Oriental herbs are reported as having potent functions for preventing many types of diseases. They also appear to have positive effects and potential capabilities for skin care. Among the many oriental herbs that are available, we chose to analyze four medicinal herbs, Korean red ginseng, Artemisia capillaries Thunb, Schizonepeta tenuifolia Briq, and Foeniculum vulgare Mill, because all are popular and considered as favorite medicinal plants in Korea. Extracts of the herbs were obtained by various methods such as using distilled water, ethyl ether, methanol, ethanol, benzene, 1-butanol, and chloroform. Nine phytochemicals were detected in the extracts: maltol, adenosine, b-pinene, menthone, pulegone, limonene, anethole, estragole, and fenchone, which reportedly have multi-functionalities. All phytochemicals were analyzed quantitatively by various chromatographic techniques such as HPLC and gas chromatography-mass (GC-MS) spectrometry. This article also presents the optimum conditions for extracting these 9 targeted phytochemical compounds that were derived from 4 popular oriental herbs, which could be useful for the efficient preparation of each phytochemical.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.489-494
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• 2008

In order to develop a potent antidementia $\beta$-secretase inhibitor from phytochemicals, $\beta$-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest $\beta$-secretase inhibitory activity of 84.5%. After purification of the $\beta$-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified $\beta$-secretase inhibitor with $IC_{50}$ inhibitory activity of $6.3{\times}10^3\;ng/mL$ ($1.56{\times}10^{-6}\;M)$ was obtained with a 0.08% solid yield. The molecular mass of the purified $\beta$-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and $\beta$-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified $\beta$-secretase inhibitory peptide inhibited $\beta$-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as $\alpha$-secretase, chymotrypsin, and elastase.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1237-1242
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• 2009

Polymethoxylated flavones (PMFs) extracted from Citrus sinensis 'Jincheng' peel were characterized by chromatographic and spectroscopic techniques. Seven individual PMF were identified. 3, 3', 4', 5, 6, 7-hexamethoxyflavone (HEX), nobiletin (NOB), heptamethoxyflavone (HEP), 5-demethylnobiletin (DN), and tangeretin (TAN) were characterized through electrospray ionization mass spectrometry (ESI-MS) in positive mode of protonated molecular ions $[M+H]^+$, the diagnostic fragment ions, together with the UV-Vis spectra and high performance liquid chromatography (HPLC) elution order from literature data. Sinensetin (SIN) and tetramethyl-O-scutellarein (SCU) were isolated and identified through their MS, $^1H$ nuclear magnetic resonance (NMR) and UV-Vis spectral studies. The levels of PMFs in peels from different cultivars of citrus fruits grown in China were determined for the first time. The results showed that C. aurantium 'Bitter orange' peel was the most promising variety for HEP. C. sinensis peel was a good source for SIN and SCU.

• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.247-256
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• 2010

A high-performance liquid chromatographic (HPLC) method was developed to determine buprofezin residues in hulled rice and fruits. The buprofezin residue was extracted with acetone and the extract was stepwise purified by liquid-liquid partition and Florisil column chromatography. For rice samples, acetonitrile/n-hexane partition was additionally employed to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate buprofezin from sample co-extractives, as detected by ultraviolet absorption at 250 nm. Recovery experiment at the limit of quantitation validated that the proposed method could evidently determine the buprofezin residue at the level of 0.02 mg/kg. Mean recoveries from hulled rice, apple, pear, and persimmon samples fortified at three tenfold levels were in the range of 80.8~85.2%, 89.1~98.4%, 88.8~95.7% and 90.8~96.2%, respectively. Relative standard deviations of the analytical method were all less than 5%, irrespective of sample types. A selected-ion monitoring LC/mass spectrometry with positive electrospray ionization was also provided to sensitively confirm the suspected residue.