Thais Guaratini

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In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The(More)
Cosmetic stability prediction relies on quantitative chemical determinations of active components after certain times and in different temperatures. However, physical stability, an important parameter in skin care products is not considered in these conditions. This study proposes the determination of cosmetic stability chemical and physical parameters(More)
We report here new chemical evidence for the generation of radical molecular ions of compounds with a conjugated pi-system (polyene) in ESI and HR-MALDI mass spectrometry. The oxidation potential of the neutral polyenes was calculated by cyclic-voltammetry and the results compared with those previously published for other complex conjugated compounds that(More)
Hyphenated techniques of gas chromatography coupled to mass spectrometer were used to determine fatty acids in eleven species of seaweeds from Fernando de Noronha archipelago. The main compounds detected in all studied species were the alcohol phytol and the fatty acids 14 : 0; 15 : 0; 16 : 0; 18 : 0; 18 : 1 n(9); 18 : 2 Δ(9,12); 20 : 4; 20 : 5. These fatty(More)
SRTXRF WAS USED TO DETERMINE AS, BA, BR, CA, CO, CR, CS, CU, DY, FE, K, MN, MO, NI, PB, RB, SR, TI, V, AND ZN IN ELEVEN SEAWEED SPECIES COMMONLY FOUND IN FERNANDO DE NORONHA: Caulerpa verticillata (J. Agardh) (Chlorophyta), Asparagopsis taxiformis (Delile), Dictyurus occidentalis (J. Agardh), Galaxaura rugosa (J. Ellis & Solander) J. V. Lamouroux, G.(More)
Fungi, including the entomopathogenic deuteromycete Metarhizium anisopliae, produce a wide diversity of secondary metabolites that either can be secreted or stored in specific developmental structures, e.g., conidia. Some secondary metabolites, such as pigments, polyols and mycosporines, are associated with pathogenicity and/or fungal tolerance to several(More)
This paper reports the chemical evidence of the balance between radical molecular ions and protonatedmolecules of xanthophylls (an oxygen-containing carotenoid) with a conjugated pi-system (polyene) and oxygen as a heteroatom in ESI and HRESI mass spectrometry. The ionization energy of neutral xanthophylls was calculated by semi-empirical methods. The(More)
Este artigo descreve a caracterização por CLAE-DAD-EM/EM e CLAE-DEC dos perfis de metabólitos secundários de extratos das folhas de Lychnophora ericoides Mart. de diferentes procedências e suas propriedades citotóxicas e antioxidantes. Extratos foliares de populações representando sete diferentes localidades foram avaliados quanto à atividade antioxidante(More)