• Natural Product Sciences
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• v.16 no.2
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• pp.116-122
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• 2010

A high-performance liquid chromatography (HPLC) with diode array detector (DAD) and electrospray ionization mass spectrometry (ESI-MS) was established for the simultaneous determination of five representative metabolites of the iridoid and phenolic classes from Rehmannia glutinosa. The optimal chromatographic conditions were obtained on an ODS column (5 mm, $4.6{\times}250\;mm$) with the column temperature at $25^{\circ}C$. The mobile phase was composed of water and acetonitrile using a gradient elution with the flow rate 0.3 mL/min. Detection wavelength was set at 205 nm. All calibration curves showed good linear regression ($r^2$ > 0.997) within test ranges. Limits of detection (LOD) and quantitation (LOQ) values were lower than 0.123 and $0.373\;{\mu}g/mL$, respectively. The developed method provided satisfactory precision and accuracy with overall intra-day and inter-day variations of 0.09 - 0.76% and 0.16 - 1.41%, respectively, and the overall recoveries of 99.03 - 102.67% for all of the compounds analyzed. In addition, effectiveness of diverse extraction methods was compared to each other for the development of standard analytic method. The verified method was successfully applied to the quantitative determination of five representative metabolites in twenty-one commercial Rehmannia glutinosa samples from different markets in Korea and China. The analytical results showed that the contents of the five analytes vary significantly with sources.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.675-682
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• 2011

This study was conducted to monitor the concentrations of 24 anti-impotence drugs and their analogues in various foods and dietary supplements, with the aim of ensuring the safety of the foods and supplements. The measurements were done in 226 samples using high performance liquid chromatography/photodiode array detector (HPLC/PDA) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Five male sexual function enhancing products have been detected as follows: acethylvardenafil (21,476 mg/kg; 15 mg/capsule from one sample), sildenafil (52,778 mg/kg, 29 mg/capsule in one sample; 71,535 mg/kg, 48 mg/capsule in one sample), and tadalafil (9,772-55,545 mg/kg, 6-33 mg/capsule in four samples). A sustainable monitoring of anti-impotence drugs and their analogues in various foods and dietary supplement is recommended.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.292-298
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• 2014

Tridemorph is a systemic morpholine fungicide for crops. The objective of this study was to develop reliable and sensitive analytical method for determination of tridemorph residues in tea samples for ensuring the food safety. Tridemorph residues in samples were extracted with acetonitrile after hydration, partitioned with saline water, and then purified using an aminopropyl ($NH_2$) SPE cartridge. The purified samples were detected and quantified using LC-ESI-MS/MS. The linear detection limits for tridemorph ranged from 0.02 to $1.0mgL^{-1}$ with a correlation coefficient of 0.9999. The method was validated using tea samples spiked with tridemorph at different concentration levels (0.02 and $0.05{\mu}gmL^{-1}$). The average recovery ranged between 75.0 and 84.7% with relative standard deviations less than 10%. The LOD and LOQ were 0.01 and $0.02mgL^{-1}$, respectively. The developed method was applied successfully to the identification of tridemorph in real tea samples obtained from different sources, and tridemorph was not detected in any of the samples. The results show that the developed analytical method is accurate and suitable for tridemorph determination in tea samples.

• 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.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.172-177
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• 2006

Hepatotoxic potential of 2, 3-dibromopropene (2, 3-DBPE) and its conjugation with glutathione (GSH) were investigated in male ICR mice. Treatment of mice with 20, 50, and 100 mg/kg of 2, 3-DBPE for 24 h caused elevation of serum alanine aminotransferase and aspartate aminotransferase activities. The hepatic content of GSH was not changed by 2, 3-DBPE. Meanwhile, the GSH content was slightly reduced when mice were treated with 2, 3-DBPE for 6 h and significantly increased 12 h after the treatment. Subsequently, a possible formation of GSH conjugate of 2, 3-DBPE was investigated in vivo. After the animals were treated orally with 20, 50, and 100 mg/kg of 2, 3-DBPE, the animals were subjected to necropsy 6, 12, and 24 h later. A conjugate of S-2-bromopropenyl GSH was identified in liver and serum treated with 100 mg/kg of 2, 3-DBPE by using liquid chromatography-electrospray ionization tandem mass spectrometry. The protonated molecular ions $[M+H]^+$ of S-2-bromopropenyl GSH were observed at m/z 425.9 and 428.1 in the positive ESI spectrum with a retention time of 6.35 and 6.39 min, respectively. In a time-course study in livers following an oral treatment of mice with 100 mg/kg of 2, 3-DBPE for 6, 12, and 24 h, the 2, 3-DBPE GSH conjugate was detected maximally 6 h after the treatment. The present results suggested that 2, 3-DBPE-induced hepatotoxicity might be related with the production of its GSH conjugate.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.729-734
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• 2005

A sensitive and selective method for quantitation of sofalcone and its active metabolite in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Plasma samples were transferred into 96-well plate using an automated sample handling system and spiked with 10 $\mu$L of 2 $\mu$g/mL $d_3$-sofalcone and $d_3$-sofalcone metabolite solutions (internal standard), respectively. After adding 0.5 mL of acetonitrile to the 96-well plate, the plasma samples were then vortexed for 30 sec. After centrifugation, the supernatant was transferred into another 96-well plate and completely evaporated at 40 ${^{\circ}C}$ under a stream of nitrogen. Dry residues were reconstituted with mobile phase and were injected into a $C_{18}$ reversed-phase column. The limit of quantitation of sofalcone and its metabolite was 2 ng/mL, using a sample volume of 0.2 mL for analysis. The reproducibility of the method was evaluated by analyzing 10 replicates over the concentration range of 2 ng/mL to 1000 ng/mL. The validation experiments of the method have shown that the assay has good precision and accuracy. Sofalcone and its metabolite produced a protonated precursor ion ([M+H]$^+$) of m/z 451 and 453, and a corresponding product ion of m/z 315 and 317, respectively. Internal standard ($d_3$-sofalcone and $d_3$-sofalcone metabolite) produced a protonated precursor ion ([M+H]$^+$) of m/z 454 and 456 and a corresponding product ion of m/z 315 and 317, respectively. The method has been successfully applied to a pharmacokinetic study of sofalcone and its active metabolite in human plasma.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.315-322
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• 2013

BACKGROUND: This study was performed for the identification and quantification of glucosinolate (GSL) contents in seven varieties of rapeseed (Brassica napus L.) sprouts cultivated under dark and light conditions. METHODS AND RESULTS: Crude glucosinolates (GSLs) were desulfated by treating with aryl sulfatase and purified using diethylaminoethyl sepharose (DEAE) anion exchange column. Individual GSLs were quantified using high-performance liquid chromatography (HPLC) with electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Eleven GSLs including six aliphatic (progoitrin, sinigrin, glucoalyssin, gluconapoleiferin, gluconapin, and glucobrassicanapin), four indolyl (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin, and neoglucobrassicin) and one aromatic (gluconasturtiin) were identified based on the fragmentation patterns of MS spectrum. Aliphatic GSLs were noted as the predominant group with average 85.2% of the total contents. The most abundant GSLs were progoitrin which was ranged at $8.14-118.68{\mu}mol/g$ dry weight (DW). The highest total GSL amounts were documented in 'Hanra' ($146.02{\mu}mol/g$ DW) under light condition and 'Mokpo No. 68' ($86.67{\mu}mol/g$ DW) in dark condition, whereas the lowest was in 'Tamra' (30.13 and $14.50{\mu}mol/g$ DW) in both conditions. The sum of aliphatic GSLs attributed > 80% in all varieties, except 'Tamra' (67.7% and 64.9% in dark and light conditions, respectively) in the total GSL accumulation. Indolyl GSLs were ranged $2.41-15.73{\mu}mol/g$ DW, accounted 2.78-33.6% of the total GSLs in rapeseed varieties. CONCLUSION(S): These results provide valuable information regarding potential beneficial GSL contents individually. This study attempts to contribute to knowledge of the nutritional properties of the different varieties of rapeseed plants. These results may be useful for the evaluation of dietary information.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.84-92
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• 2010

Antibacterial compound from Bacillus subtilis MJP1 was purified using C18 Sep-Pak cartridge, ion exchange chromatography, and gel filtration chromatography. The purified antibacterial compound showed antibacterial activity against Listeria monocytogenes, Bacillus subtilis, Staphylococcus aureus subsp. aureus, and Enterococcus faecalis. The purified antibacterial compound was found to be stable at $100^{\circ}C$ for 5 min and in the pH range of 3.0~9.0, but it was unstable at pH 10.0. It was inactivated by proteinase K and pronase E, and heat treatment at $121^{\circ}C$ for 15 min, but it was stable with lipase and $\alpha$-amylase treatment, which indicated its proteineous nature. Ultra performance liquid chromatography and electrospray ionization tandem mass spectrometry analysis were used to identify the purified antibacterial compound and confirmed the existence of two peptides (3356.54 Da, 3400.5244 Da).

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.326-333
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• 2009

Heterocyclic aromatic amines (HCAs) are mutagenic and carcinogenic substances that are formed during the heating of protein-rich foods. HCAs are generally found at low amounts in a complex matrix, which requires sophisticated analysis. In this study, HCAs were extracted from lyophilized fish and shellfish samples using solid-phase extraction (SPE) and determined by liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI-MS). The HCA recoveries in the fish and shellfish ranged from 15.7 to 74.7% with standard deviations from 0.2 to 7.63%. And HCA concentrations ranged from 0.8 to 1,117.7 $ng/g^{-1}$ in cooked food samples. 1-methyl-9H-pyrido[3,4-b]indole (Harman), 9H-pyrido[3,4-b]indole (Norharman), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were the most abundant HCAs formed in the muscle of fried mackerel, at levels of 1,117.7, 926.6, and 133.7 ng/g, respectively. 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-aminodipiryrido[1,2-a:3,2-d]imidazole(Glu-P-2), 2-amino-9H-pyrido[2,3-b]indole(A${\alpha}$C), 2-amino-3methyl-9H-pyrido [1,2-a:3,2-d]imidazole(MeA${\alpha}$C), 2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline (TriMeIQx), 2-amino-3,7,8-trimethylimidazo [4,5-f]quinoxaline(7,8-DiMeIQx), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) were only detected by small quantities ranged from 1.5 to 98.6 ng/g. Overall, this study provides useful information on HCA levels in fish and shellfish products consumed in Korea.

• Korean Journal of Medicinal Crop Science
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• v.27 no.6
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• pp.419-426
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• 2019

Background: This study aimed to identify antioxidant compounds from the seeds of Dolichos lablab L. by bioassay-guided isolation and recrystallization. Methods and Results: The water layer of D. lablab L. seed extract inhibits intracellular reactive oxygen species (ROS) expressing the 2',7'-dichlorofluorescein diacetate (DCF-DA), Cu/Zn superoxide dismutase (SOD) and catalase genes, as determined by quantitative real-time PCR (qRT-PCR). Two compounds were purified from the water layer of the seeds of D. lablab L. using column chromatography and prep-high performance liquid chromatography (HPLC). Using nuclear magnetic resonance (NMR) and electrospray Ionization mass spectrometry (ESI-MS), their chemical structures were identified as 5-[(2-acetyl-2,3-dihydro-1H-indazol-1-yl)carbonyl]-4,5-dihydro-3H-furan-2-one (C₁₄H₁₄N₂O₄) and stachyose. Conclusions: Two active antioxidant compounds were purified from the seed extract of D. lablab L. seed extract and the structures of these compounds were identified as C₁₄H₁₄O₄N₂ and stachyose.