Metabolomics has focused on toxicological applications to (1) understand the mechanisms of toxicity, (2) identify novel biomarkers of toxicity, and (3) provide in vivo assessment in animal models through simple and fast methods to date. The toxicological effects of nonylphenol (NP) were evaluated after intraperitoneal injection of rats with 0, 50, and 250 mg kg(-1) day(-1) NP for four consecutive days. In the nontargeted approach, different extraction conditions were introduced to investigate the effects of NP on rats through gas chromatography/mass spectrometry (GC/MS). The GC/MS data obtained were further analyzed with partial least-squares discriminant analysis to compare toxicological effects between control and treated groups. The targeted approach was also used in combination with GC/MS to quantify endocrine hormones and to identify possible biomarkers in rat urine under optimal extraction conditions. In addition, we considered the metabolic trajectory to examine the metabolite profiles and patterns related to steroid metabolism in rats that were treated with NP, considering both treatment amount and time. The data suggest that tetrahydrocorticosterone and 5alpha-tetrahydrocorticosterone are possible urinary biomarkers of NP-induced toxicity. This metabolomic approach is a promising tool to assist with screening in toxicological studies.

BackgroundLead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population.MethodsThis population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0–83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer.ResultsThe geometric mean, median and 95th percentile of blood Pb was 1.82 µg/dL, 1.83 µg/dL, and 3.78 µg/dL, respectively. The respective values were 2.92 µg/L, 2.87 µg/L, 9.12 µg/L for Hg, and 0.56 µg/L, 0.59 µg/L, 2.20 µg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0–4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age.ConclusionThis study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.

This study has attempted to establish an analysis method through validation against heavy metals in the body (Pb, Cd and Hg) using ICP-MS and Gold amalgamation and find out the relevance between heavy metal and Alzheimer’s disease after analyzing the distribution of heavy metal concentration (Pb, Cd and Hg) and correlations between a control group and Alzheimer’s disease group. In this study, Pb and Cd levels in the blood and serum were validation using ICP-MS. For analysis of Hg levels in the blood and serum, the gold amalgamation-based ‘Direct Mercury Analyzer’ has been used. According to an analysis on the heavy metal concentration (Pb, Cd and Hg concentration) in the blood, Cd concentration was high in the Alzheimer’s disease group. In the serum, on the contrary, Pb and Hg were high in the Alzheimer’s disease group. For analysis of correlations between heavy metal levels in the blood and serum and Alzheimer’s disease, t-test has been performed. Even though correlations were observed between the blood lead levels and Alzheimer’s disease, they were statistically insignificant because the concentration was higher in a control group. No significance was found in Cd and Hg. In the serum, on the other hand, no statistical significance was found between the heavy metal (Pb, Cd and Hg) and Alzheimer’s disease. In this study, no statistical significance was observed between heavy metal and decrease in cognitive intelligence. However, it appears that a further study needs to be performed because the results of the conventional studies were inconsistent.

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This study aimed to measure phytoestrogen contents in health functional foods (HFFs) to alleviate menopausal symptoms that are commercially available in South Korea. A sensitive and selective method using gas chromatography-mass spectrometry (GC-MS) for the monitoring of 21 phytoestrogens was developed and fully validated. Phytoestrogens were extracted by liquid-liquid extraction using methyl tert-butylether as the solvent. Food samples were enzymatically hydrolyzed with β-glucuronidase/arylsulfatase. Before GC-MS, the analytes were derivatized to their trimethylsilyl derivatives by incubation with N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane for 30 min at 80 C. The calibration curves showed good linearity (r 2 > 0.99) in the range of interest for each analyte. The limits of detection and quantification of the 21 phytoestrogens were in the ranges of 0.5-20 and 1-50 ng/mL, respectively. The intra-and inter-day precisions were all below 15.7%. These multivariate procedures were efficient in determining the optimal conditions using peak heights as responses.