Effects of semicarbazide exposure on endocrine pancreas morphology

2016

J. Agric. Food Chem.

Semicarbazide (1) is a widespread genotoxic food contaminant originating as a metabolic byproduct of the antibiotic nitrofurazone used in fish farming or as a thermal degradation product of the common flour additive azodicarbonamide. The goal of this study is to develop a simple and sensitive high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method for the detection of compound 1 in food products. In comparison to existing methods for the determination of compound 1, the reported method combining online precolumn derivatization and HPLC-FLD is less labor-intensive, produces higher sample throughput, and does not require the use of expensive analytical instruments. After validation of accuracy and precision, this method was applied to determine the amount of compound 1 in fish and bread samples. Comparative studies using an established liquid chromatography coupled with tandem mass spectrometry method did not yield systematically different results, indicating that the developed HPLC-FLD method is accurate and suitable for the determination of compound 1 in fish and bread samples.

Section: Introductionmentioning

confidence: 96%

Automated In-Injector Derivatization Combined with High-Performance Liquid Chromatography–Fluorescence Detection for the Determination of Semicarbazide in Fish and Bread Samples

2016

J. Agric. Food Chem.

Facile Formation of a DNA Adduct of Semicarbazide on Reaction with Apurinic/Apyrimidinic Sites in DNA

2016

Chem. Res. Toxicol.

Mutagenic semicarbazide (SEM) is a hydrazine-containing food contaminant found in a wide variety of foods. Despite decades of research, the toxicity of SEM remains incompletely understood. In this study, we demonstrate for the first time that SEM reacts rapidly with apurinic/apyrimidinic sites in an endogenous DNA lesion to form covalently bonded DNA adducts in vitro and in bacteria. Specifically, we performed high-performance liquid chromatography with high accuracy and tandem mass spectrometry to characterize the DNA adduct formed by reacting SEM with 2'-deoxyribose and single- and double-stranded oligonucleotides containing abasic sites under physiologically relevant conditions. By analyzing the reaction mixture at different time points, the reaction kinetics of SEM with DNA was also elucidated. Moreover, by using a highly sensitive and selective liquid chromatography-tandem mass spectrometry method, we show that SEM induces the dose-dependent formation of DNA adducts in Escherichia coli. The results from our studies provide the first direct evidence suggesting that SEM may exert genotoxicity by forming covalently bonded DNA adducts.

Quantitation of the DNA Adduct of Semicarbazide in Organs of Semicarbazide-Treated Rats by Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry: A Comparative Study with the RNA Adduct

Wong

2016

Chem. Res. Toxicol.

Semicarbazide is a widespread food contaminant that is produced by multiple pathways. However, the toxicity of semicarbazide to human health remains unclear. Using a highly accurate and sensitive isotope-dilution liquid chromatography-tandem mass spectrometry method, we identified and quantitated in this study for the first time the DNA and RNA adduct of semicarbazide in DNA/RNA isolated from the internal organs of semicarbazide-exposed rats. The analysis revealed a dose-dependent formation of the adducts in the internal organs of the semicarbazide-dosed rats and with the highest adduct levels identified in the stomach and small intestine. Furthermore, results showed significantly higher levels of the RNA adduct (4.1-7.0 times) than that of the DNA adducts. By analyzing DNA/RNA samples isolated from rat organs in semicarbazide-dosed rats at different time points postdosing, the adduct stability in vivo was also investigated. These findings suggest that semicarbazide could have exerted its toxicity by affecting both the transcription and translation processes of the cell.