Time filter

Source Type

Yangsan, South Korea

Choi Y.H.,Yeungnam University | Zhou W.,Yeungnam University | Oh J.,Yeungnam University | Choe S.,Southern District Office | And 3 more authors.
Bioorganic and Medicinal Chemistry Letters

In spite of the critical role of the natural products in drug discovery, surprising little attention has been placed on endangered and rare plant species that could play a pivotal role in pharmaceutical and fiber development. Protein tyrosine phosphatase-1B (PTP1B), which blocks insulin signaling, has been gaining interest to be a promising therapeutic target for the treatment of type 2 diabetes mellitus. Bioassay-guided fractionation on the leaves of Rhododendron brachycarpum G. Don (Ericaceae) yielded seven PTP1B inhibitory triterpenoids, including a new triterpene, rhododendric acid A (1). Their PTP1B inhibitory potency and their lipophilicity were investigated to provide a feasible scaffold that may overcome the innate limitation of the previously reported PTP1B inhibitors. © 2012 Elsevier Ltd. All rights reserved. Source

Cho Y.A.,South Korean National Fisheries Research and Development Institute | Kim E.-M.,South Korean National Fisheries Research and Development Institute | Kim M.-J.,Southern District Office | Kang J.-H.,South Korean National Fisheries Research and Development Institute | And 5 more authors.
Food Control

Two species of mitten crab, Eriocheir sinensis and Eriocheir japonica, are commercially valuable in Korea. Millions of their juveniles have been released in attempts to restore ecological habitat and enhance fishery resources. Due to their habitat's singularity, exact species identification should be conducted before juveniles are released. In this study, we used a highly conserved region of the mitochondrial cytochrome b (cyt b) gene to distinguish E.sinensis from E.japonica. We designed a primer set to amplify part of the mitochondrial cyt b gene of both species and obtained 1024 base pairs (bp) of polymerase chain reaction (PCR) product. These PCR products were digested with the restriction enzyme MboII and the species-specific restriction fragment length polymorphism (RFLP) patterns were analyzed. Also, we designed primers for the rapid identification of cyt b gene (498bp) to distinguish E.sinensis. PCR-RFLP and PCR using new primers are a fast and inexpensive method to access species identification. This simple and rapid method can provide useful information for E.sinensis and E.japonica species identification. © 2013 Elsevier Ltd. Source

Kim J.,National Forensic Service | Ji D.,Keimyung University | Kang S.,Keimyung University | Park M.,National Forensic Service | And 4 more authors.
Journal of Pharmaceutical and Biomedical Analysis

Natural and synthetic opioids have efficient analgesic activity but can also be addictive. Thus, the determination of opioids and their metabolites in biological specimens is of interest in clinical and forensic toxicology laboratories. The analysis of drugs in hair provides valuable information on previous chronic drug use and has been successfully applied to the diagnosis of drug abuse, tolerance, compliance and gestational drug exposure. Despite the abuse of prescription opioids along with heroin and other illegal opiates, few studies have been conducted on the simultaneous determination of the broad range of opioids covering those drugs in hair. In the present study, an analytical method for the simultaneous detection in hair of 18 opioids and metabolites considered to have a high abuse risk based on the results of urine drug screening was established and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the purpose of clinical and forensic applications. The drugs and metabolites were extracted from hair using methanol and analyzed using LC-MS/MS. The validation results proved that the method was selective, accurate and precise with acceptable linearity within calibration ranges. No significant variation was observed by different sources of matrices. The limits of detection and the limits of quantification ranged from 0.05 to 0.25. ng/10. mg hair and from 0.05 to 0.5. ng/10. mg hair, respectively. The developed method was successfully applied to 15 hair samples from opioids users. This method will be very useful for monitoring the inappropriate use of opioid drugs. © 2013 Elsevier B.V. Source

Shin M.,Keimyung University | Ji D.,Keimyung University | Kang S.,Keimyung University | Yang W.,National Forensic Service | And 2 more authors.
Archives of Pharmacal Research

A recent trend in urine drug testing in forensic and clinical toxicology has been the simultaneous determination of different chemical groups of target drugs, which are selected based on their local popularity. Rapid multiple drug analysis, made possible by the use of liquid chromatography-tandem mass spectrometry (LC/MS/MS), has become more widely used, especially in workplace drug testing. Therefore, in the present study, a method for simultaneously analyzing 35 drugs of abuse and relevant metabolites that are most prevalent in Korea, using LC/MS/MS with polarity switching electrospray ionization, was developed and validated. The drugs and metabolites in urine were extracted by using mixed mode strong cation exchange polymeric solid phase extraction cartridges after enzymatic hydrolysis and were then injected into the LC/MS/MS system. The validation results for selectivity, linearity, intra- and inter-assay precision and accuracy for this method were satisfactory, while the results for matrix effects and recovery showed significant variance among the urine samples from different sources. The limits of detection ranged from 0.1 to 10 ng/ml and the limits of quantification were from 1 to 10 ng/ml. To reduce the matrix effects in authentic samples, two different quantitative approaches were compared: quantification using calibration standards prepared by the drug-free pooled urine matrix and quantification using the standard addition. Of these, the latter method was found to be the most suitable. The method developed in this study will be very useful for forensic and clinical toxicology laboratories to adopt for monitoring the inappropriate use of controlled drugs. © 2013 The Pharmaceutical Society of Korea. Source

Choe S.,Southern District Office | Woo S.H.,Central District Office | Kim D.W.,Central District Office | Park Y.,Southern District Office | And 4 more authors.
Analytical Biochemistry

After gas chromatography-mass spectrometry (GC-MS) analysis, data processing, including retention time correction, spectral deconvolution, peak alignment, and normalization prior to statistical analysis, is an important step in metabolomics. Several commercial or free software packages have been introduced for data processing, but most of them are vendor dependent. To design a simple method for Agilent GC/MS data processing, we developed an in-house program, "CompExtractor", using Microsoft Visual Basic. We tailored the macro modules of an Agilent Chemstation and implanted them in the program. To verify the performance of CompExtractor processing, 30 samples from the three species of the genus Papaver were analyzed with Agilent 5973 MSD GC-MS. The results of CompExtractor processing were compared with those of AMDIS-SpectConnect processing by hierarchical cluster analysis (HCA) and principal component analysis (PCA). The two methods showed good classification according to their species in HCA. The PC1 + PC2 scores were 54.32-63.62% for AMDIS-SpectConnect and 56.65-85.92% for CompExtractor in PCA. Although the CompExtractor processing method is an Agilent GC-MS-specific application and the target compounds must be selected first, it can extract the target compounds more precisely in the raw data file with batch mode and simultaneously assemble the matrix text file. © 2012 Elsevier Inc. All rights reserved. Source

Discover hidden collaborations