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A sulfated polysaccharide fraction from the red alga Gracilaria intermedia (PLS) was obtained by papain digestion (60 °C, 30 min). The extract was subjected to colorimetry and turbidimetry analysis, Fourier transform infrared (FTIR) spectroscopy, 1 H, 13 C and 2 D 1 H COSY nuclear magnetic resonance (NMR) and gas chromatography/mass spectrometry analysis. Antioxidant activity tests were performed (chelation of ferrous ion, total antioxidant capacity, and scavenging of DPPH radicals); significant activity of the extract indicated that these polysaccharides may be used as non-synthetic antioxidants. The rheological behavior of aqueous polysaccharide solutions was studied at 25 ± 1 °C using steady-shear and dynamic oscillatory measurements. All the solutions analyzed showed pseudoplastic behavior and potential to act as a thickening agent, as proved through a preliminary comparison with a commercial product used for this application.

Um novo derivado da piperazina, 5-oxopiperazinio-3-sulfonato monohidratado, foi produzido a partir de uma rota sintética simples como resultado da adição do íon bisulfito, HSO 3 -, ao anel e do ataque nucleofílico de moléculas de água a moléculas de pirazina. O material isolado foi caracterizado por RMN, espectrometria de massa, infravermelho e difração de raios-X.A new derivative of piperazine, 5-oxopiperazinium-3-sulfonate monohydrate, was produced from a simple synthetic route as a result of the nucleophilic addition to HSO 3 -bisulphite ion and of the nucleophilic attack of water molecules on pyrazine molecules. The isolated material was characterized by means of NMR, mass spectrometry, infrared, and X-ray diffraction.

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