Browsing by Author "Pereira, David M."
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- A gas chromatography-mass spectrometry multi-target method for the simultaneous analysis of three classes of metabolites in marine organismsPublication . Pereira, David M.; Vinholes, Juliana; de Pinho, Paula Guedes; Valentao, Patricia; Mouga, Teresa; Teixeira, Natercia; Andrade, Paula B.In this work a fast and simple multi-target gas chromatography–mass spectrometry (GC–MS) method for the simultaneous detection and absolute quantification of amino acids, fatty acids and sterols in marine organisms is proposed. The methodology was applied to the characterization of the echinoderm Marthasterias glacialis Linnaeus spiny sea star extracts. The main factors influencing the extraction of target compounds were evaluated by using different extraction procedures, solvent systems and temperature conditions and a comparison with a reference technique was performed. The most suitable procedure, capable of successfully extract the three classes of target compounds, was ethanol as solvent at 40 1C under magnetic stirring. Good analytical parameters were obtained since calibrations curves for the 40 compounds under analysis (15 amino acids, 16 fatty acids and 9 sterols) showed regression coefficients (r 2 ) ranging from 0.9844 to 0.9978, with low RSD (from 0.00 to 9.45%), and detection limits varying from 0.03 to 15.40 mg/L. The RSD values for intra- and interday variations studies were also good (RSDo13.5%, for both) and recoveries were higher than 92%. Variation in samples from different harvests and origins and their chemical composition during the year is reported. The fact that no previous treatment of samples is required can make this a useful technique for metabolite profiling in marine organisms, among others, both in biomedical and nutritional studies. Moreover, due to the fast and robust character of the proposed method it seems to be suitable for the implementation as routine analysis.
- HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling of cytotoxic carotenoids from the echinoderm Marthasterias glacialis (spiny sea-star)Publication . Ferreres, Federico; Pereira, David M.; Gil-Izquierdo, Angel; Valentão, Patrícia; Botelho, João; Mouga, Teresa; Andrade, Paula B.An HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling analysis was conducted on the marine echinoderm Marthasterias glacialis (spiny sea-star). Bio-guided purification of the methanolic extract led to the isolation of several carotenoids, namely zeaxanthin, astaxanthin and lutein. These compounds were characterized using both UV–Vis characteristics and MS spectra interpretation. No previous works addressed the MS analysis of carotenoids present in this organism. The purified carotenoid fraction displayed a strong cell proliferation inhibition against rat basophilic leukemia RBL-2H3 (IC25 5 268 mg/mL) cancer cell line. Against healthy V79 (rat lung fibroblasts (IC25 5411 mg/mL)) cell line, however, toxicity was lower, as it is desired for anti-cancer molecules. This study suggests that M. glacialis may constitute a good source of bioactive compounds that can be used as lead compounds for the pharmaceutical industry.