Chromatographic Method for Monitoring of Pesticide Residues and Risk Assessment for Herbal Decoctions Used in Traditional Korean Medicine Clinics.

The presence of pesticide residues in herbs and the herbal products derived from them raises serious health concerns. This study was conducted to investigate the residual pesticide concentrations and assess potential human health risks from herbal medicines used in traditional Korean medicine clinics. A total of 40 samples of herbal decoctions were collected from 10 external herbal dispensaries. The pesticide residues were analyzed by the multiresidue method for 320 different pesticides using liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography tandem mass spectrometry (GC-MS/MS). As a result of the monitoring, carbendazim was detected at 0.01 and 0.03 µg/g in eight samples and no pesticide was detected in the other herbal decoctions. Carbendazim was set for each individual item as less than 0.05 µg/g in Paeoniae radix, less than 0.05 µg/g in Cassiae semen, less than 2.0 µg/g in Lycii fructus, and less than 10 µg/g in Schisandrae fructus (dried). Therefore, the results of this study suggested that the detected pesticide residues in herbal decoctions could not be considered as posing a serious health risk.

GC-MS-based quantitative signatures of cytochrome P450-mediated steroid oxidation induced by rifampicin.

BACKGROUND: Drug-induced cytochrome P450 (CYP) activity affects endocrine function and drug clearance rates, leading to the development of unpredictable pathologic and toxicologic risks. METHODS: Urinary steroid profiling based on gas chromatography-mass spectrometry (GC-MS) was used for simultaneous quantification of CYP-mediated regioselective hydroxysteroids and their substrates, including 26 androgens, 9 estrogens, 5 progestins, and 7 corticoids. The quantitative data were visualized using a hierarchically clustered heat map to allow identification of CYP-mediated steroid signatures. Twelve healthy subjects were orally administered 600 mg of rifampicin a day for 7 days, and their CYP enzyme activity was evaluated. RESULTS: Using GC-MS, all 47 steroids were well separated with good peak shapes. This assay had good linearity (r > 0.994) in a dynamic range, and the interassay imprecision (% CV) and inaccuracy (% bias) were 3.0%-15.6% and 98.0%-109.2%, respectively. Administration of the CYP3A4 inducer rifampicin produced distinct differences in CYP3A4 and CYP11B1, CYP19A1, HSD11B, and HSD17B, which were indicated by their heat map-visualized steroid signatures. CONCLUSIONS: This CYP-mediated steroid signature profile allows simultaneous assessment of CYP1A, CYP1B, CYP2C, CYP3A, CYP11B, CYP17A, CYP19A, and CYP21A in urine samples. This method could therefore be a useful tool for assessing drug efficacy.

Cell chip to detect effects of graphene oxide nanopellet on human neural stem cell.

The graphene oxide (GO) nanopellet, a potentially useful carbon-based material, recently started being applied in cell-based research areas. Its toxicity assessment using the neural-stem-cell-based chip has not been thoroughly reported yet, though. Herein, a cell chip was fabricated to electrochemically detect the toxic effects of GO nanopellets on HBl.F3 cells. The RGD peptide was immobilized on the gold electrode surface to enhance the binding affinity of the HBl.F3 cells to the electrode surface. A clear redox peak appeared when the HB1.F3 cells were analyzed via cyclic voltammetry. The GO nanopellet was analyzed via Raman spectroscopy to confirm its distinct structural characteristics that normally differ from those of graphite oxide. After GO was added to the HB1.F3 cells, differential pulse voltammetry was performed to discover the toxic effects of GO nanopellets on HB1.F3 cells. A negative correlation was achieved between the concentration of the GO nanopellets and the cell viability, which was verified via both MTT assay and a microscopic imaging tool. Thus, these electrochemical tools can be usefully applied to the toxicity assessment of various kinds of carbon-based materials.

Blocking the phosphatidylinositol 3-kinase pathway inhibits neuregulin-1-mediated rescue of neurotoxicity induced by Aß1-42.

OBJECTIVES: Neuregulin-1 (NRG1) has an important role in both the development and the plasticity of the brain as well as neuroprotective properties. In this study, we investigated the downstream pathways of NRG1 signalling and their role in the prevention of Aß1-42 -induced neurotoxicity. METHODS: Lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and TUNEL staining were assayed to examine the neuroprotective properties in primary rat cortical neurons. KEY FINDINGS: The inhibition of PI3K/Akt activation abolished the ability of NRG1 to prevent Aß1-42 -induced LDH release and increased TUNEL-positive cell count and reactive oxygen species accumulation in primary cortical neurons. CONCLUSIONS: Our results demonstrate that NRG1 signalling exerts a neuroprotective effect against Aß1-42 -induced neurotoxicity via activation of the PI3K/Akt pathway. Furthermore, this suggests that NRG1 has neuroprotective potential for the treatment of AD.

Changes in steroid metabolism among girls with precocious puberty may not be associated with urinary levels of bisphenol A.

Precocious puberty (PP) refers to the appearance of physical and hormonal signs of pubertal development at an abnormally early age. Urinary steroid signatures obtained from 42 patients with central PP and 40 patients with peripheral PP were assessed to compare metabolic changes. Levels of androgens such as testosterone, androstenedione, androstenediol, 16α-hydroxy-dehydroepiandrosterone, and 5α-androstenedione tended to be high in both PP groups, and the level of 17ß-estradiol was higher in the central-PP group (P<0.01) than in the peripheral-PP and 32 age-matched healthy girls. Altered steroid metabolism was also associated with urinary BPA levels, and levels of testosterone, 17ß-estradiol, and pregnenolone were significantly increased among individuals with high BPA levels. In particular, a correlation was observed between estrogen metabolism and BPA levels irrespective of the type of PP. These findings suggest that in girls, BPA exposure causes metabolic changes in steroidogenesis, but not the early onset of PP.

Extractive ethoxycarbonylation in high-temperature gas chromatography-mass spectrometry based analysis of serum estrogens.

A comprehensive gas chromatography-mass spectrometry (GC-MS)-based profiling was developed as a practical assay for quantification of 18 endogenous estrogens in serum samples. The present GC-MS method was conducted with the two-phase extractive ethoxycarbonlyation (EOC) of the phenolic hydroxy groups of estrogen with ethyl chlorformate combined with the non-polar n-hexane extraction. The subsequent perfluoroacylation of aliphatic hydroxy groups with pentafluoropropionyl anhydride (PFPA) was conducted. The serum samples were separated through a high temperature GC column (MXT-1) within an 8-min run and analyzed in selected-ion monitoring mode with good chromatographic properties for 18 estrogens as their EOC-PFP derivatives. The limit of quantification (LOQ) was 0.025-0.10 ng/mL for most estrogens analyzed except for E3 and 2-OH-E3 (0.5 ng/mL each). The devised method was found to be linear over a 10(3)-fold concentration range with a correlation coefficient (r(2)>0.992), whereas the precision (% CV) and accuracy (% bias) ranged from 3.1 to 16.3% and from 93.5 to 111.1%, respectively. Decreased 2-methoxy-17ß-estradiol levels were confirmed in patients with preeclampsia than healthy pregnant women. This technique can be used for a clinical diagnosis as well as understanding the pathogenesis in estrogen-related disorders.