DEFAR - Artigos publicados em periódicos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531

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2020 - 20213

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Data inicial: 2020Assunto: search.filters.subject.Mass spectrometry

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    A high throughput approach for determination of dermorphin in human urine using LC-HRMS and LC-MS/MS for doping control purposes.
    (2020) Castro, Juliana de Lima; Martucci, Maria Elvira Poleti; Pereira, Henrique Marcelo Gualberto; Sousa, Valéria P. de
    Dermorphin is a peptide with analgesic actions similar to morphine, but with greater effect and less potential to cause tolerance. The use of dermorphin has been documented in race horses, and its use in humans has already been reported. Considering the potential advantages from the use of dermorphin over morphine, a method to monitor it, and its main metabolite dermorphin (1-4), in humans becomes necessary for doping control. Here, we present two orthogonal methods for this purpose: a high-throughput liquid chromatography coupled to high resolution mass spectrometry (HRMS) as an Initial Testing Procedure and liquid chromatography-tandem mass spectrometry (MS/MS) in the Selected Reaction Monitoring (SRM) acquisition mode for a Confirmation Procedure. For urine samples pre-treatment through a mixed-mode weak cation exchange solid phase extraction (WCX-SPE) emerged as an effective approach to extract peptides from the biological sample. For the HRMS analysis, a Full-MS scan acquisition mode was selected to detect the exact masses of dermorphin and dermorphin (1-4) at m/z 803.37226 and 457.20816, respectively. The SRM method used in the MS/MS confirmation protocol presented high specificity and sensitivity. The selected product ions for dermorphin were 602.2, 202.1 and 574.3 and for dermorphin (1-4) were 207.1, 223.1 and 235.1. Both methods were evaluated for specificity, repeatability, carryover, matrix effects and recovery. No carryover and matrix effects were detected. The Limit of Detection for Initial Testing Procedure and the Limit of Identification for Confirmation Procedure was 2,5 ng/mL. Also, specificity and robustness were acceptable for the application. Together, the developed methods proved to be efficient for the analysis of dermorphin and metabolite for human doping control purpose.
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    Removal of dexamethasone by oxidative processes : structural characterization of degradation products and estimation of the toxicity.
    (2021) Quaresma, Amanda de Vasconcelos; Rúbio, Karina Taciana Santos; Taylor, Jason Guy; Sousa, Bianca Aline de; Silva, Silvana de Queiroz; Werle, Alceni Augusta; Afonso, Robson José de Cássia Franco
    Dexamethasone (DEX) belongs to a class of steroid hormones that can potentially be harmful due to their endocrine disrupting properties. The efficient elimination of DEX during the treatment of drinking water is needed to ensure that the health of both human and aquatic species are protected. Thus different oxidative processes were investigated in order to assess the effect of these procedures and conditions on DEX. Aqueous solutions of DEX were treated by conventional chlorination ([NaClO]=10 mg L− 1 ) and advanced oxidative processes (ozonation – [O3]=8 mg L− 1 ; photocatalysis – [TiO2]=120 mg L− 1 and UV-C; photolysis – UV-C). The most and least efficient processes for DEX removal were ozonation (95%) and chlorination (54%), respectively. In total, 16 degradation products were identified and characterized by high-resolution mass spectrometry and only two have been proposed in previous reports. Chemical structures of the degradation products were proposed and alcohol oxidation, ozonolysis and decarboxylation were the main chemical transformations observed. The toxicities of DEX and its derivatives were evaluated by following methods: MTT assay (HepG2 cell), ECOSAR (acute and chronic toxicity) and molecular docking (AutoDock). MTT assay results demonstrated that only a mixture DEX and the chlorinated derivative were toxic at high concentrations. ECOSAR analysis showed that products formed from dehydration and fluoride elimination were more toxic than intact DEX, mainly for fish and Daphnid and to a lesser extent for green algae. The docking study revealed that these degradation products were not capable of making hydrogen bonds with residual amino acids GLN570, GLN642 and CYS736, but were stable at the glucocorticoid receptor indicating the possibility of being toxic to humans.
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    Dereplication of Palicourea sessilis ethanol extracts by UPLC-DAD-ESI-MS/MS discloses the presence of hydroxycinnamic acid amides and the absence of monoterpene indole alkaloids.
    (2020) Samulski, Gabriela Bontempo; Gontijo, Douglas da Costa; Moreira, Nayara Couto; Brandão, Geraldo Célio; Oliveira, Alaíde Braga de
    Secondary metabolites characterization of ethanol extracts of Palicourea sessilis leaves and stems by UPLC-DAD ESI-MS/MS led to putative identification of hydrolysable tannins in leaf extract (ESI negative mode) while hydroxycinnamic acid amides (HCA) such as N-p-coumaroylputrescine and N-feruloylagmatine were detected in both leaf and stems extracts in the ESI positive mode. Secondary metabolites quantification data showed a higher content of total phenolic in the leaf extract while the total alkaloids contents are statistically equivalent in both of the extracts. Furthermore, monoterpene indole alkaloids were not detected in both extracts. The presence of HCA is here firstly reported for a Palicourea species. This finding increases the classes of secondary metabolites occurring in this genus.