Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Development of a new HPLC-based method for 3-nitrotyrosine quantification in different biological matricesPublication . Teixeira, Dulce; Prudêncio, Cristina; Vieira, MónicaThe nitration of tyrosine residues in proteins is associated with nitrosative stress, resulting in the formation of 3-nitrotyrosine (3-NT).1 3-NT levels in biological samples have been associated with numerous physiological and pathological conditions. Hence several attempts have been made in order to develop methods that accurately quantify 3-NT in these matrices.The aim of this study was to develop a simple, rapid, low-cost and sensitive high-performance liquid chromatography (HPLC)-based 3-NT quantification method. Methods All experiments were performed on an Hitachi LaChrom Elite® HPLC system. The method was validated according to International Conference on Harmonisation (ICH) guidelines for serum samples. Additionally, other biological matrices were tested, namely whole blood, urine, B16 F-10 melanoma cell line, growth medium conditioned with the same cell line, bacterial and yeast suspensions. Results From all the protocols tested, the best results were obtained using 0.5% CH3COOH:MeOH:H2O (15:15:70) as mobile phase, with detection at wavelengths 215, 276 and 356 nm, at 25 °C, and using a flow rate of 1 mL min−1. By using this protocol, it was possible to obtain a linear calibration curve, limits of detection and quantification in the order of μg L−1, and a short analysis time (<15 min per sample). The developed protocol allowed the successful detection and quantification of 3-NT in all biological matrices tested, with detection at 356 nm. Conclusion This method, successfully developed and validated for 3-NT quantification, is simple, cheap and fast. These features render this method a suitable option for analysis of a wide range of biological matrices, being a promising useful tool for both research and diagnosis activities.
- Development of a chromatographic method for simultaneous analysis of glutathione formsPublication . Teixeira, Dulce; Coelho, Pedro; Prudêncio, Cristina; Azenha, Manuel; Vieira, MónicaReduced glutathione (GSH)is the most abundant low molecular weight thiol-containing tripeptide (glycine, cysteine, and glutamate) which is synthesized in the cells. GSHplays critical roles in protecting cells from oxidative damage and the toxicity of xenobiotics. Besides, it is also involved in the regulation of intracellular redox homeostasis, which leads to its oxidation into oxidized glutathione (GSSG). Determining the ratio of GSH/GSSG in different biological samples is a major procedure for the evaluation of an individual’s oxidative status and can be a potential biomarker of oxidative stress.
- Development of a method based on HPLC-DAD for the detection and quantification of glutamate and gamma-aminobutyric acidPublication . Machado, Patrícia; Teixeira, Dulce; Vieira, Mónica; Prudêncio, CristinaWith the increasing incidence of neurodegenerative diseases, the need arose to study several molecules that may be useful to the study of new therapies and to treat the symptoms that come with these diseases, as is the case of depression. GABA and glutamate have a very important role in the homeostasis of the organism and molecules of interest and potential from the point of view of diagnosis are revealed. HPLC is a method that allows the detection and quantification of various analytes in different biological matrices, allowing rapid results with high precision, sensitivity and specificity.