Comparison of diode array and electrochemical detection in the C30 reverse phase HPLC analysis of algae carotenoids

Qualitative and quantitative determination of carotenoids pigments can provide valuable information about the organisms in which this important class of compounds is found. In the HPLC analysis of pigments, diode array (DAD), electrochemical (ED) and other kinds of detector may be used. The aim of this work is to develop an HPLC method using a C30 column to identify and quantify sixteen different pigments from algae. A further aim is to compare precision and accuracy obtained by DAD and ED. ED is normally more sensible than DAD. On the other hand, the highest precision and accuracy was obtained with DAD. In conclusion, the method was efficient for quantitative and qualitative analyses of pigments from cyanobacteria and different microalgae classes. Their pigment patterns for several organisms are also discussed.A determinação qualitativa e quantitativa de carotenóides pode fornecer diferentes e importantes informações sobre os organismos que os contêm. Na análise de pigmentos por HPLC diversos detectores podem ser utilizados, como diode array (DAD) e eletroquímico (ED). O presente trabalho tem como objetivo desenvolver um método por HPLC utilizando uma coluna C30 para a identificação e quantificação de dezesseis pigmentos em diferentes classes de algas, além de comparar as respostas obtidas nos detectores DAD e ED por meio da análise dos resultados de precisão e exatidão. Apesar do ED ser geralmente um detector mais sensível que o DAD, os resultados de precisão e exatidão foram mais satisfatórios para o DAD. O método desenvolvido foi eficiente para a análise quantitativa dos pigmentos de cianobactérias e diferentes classes de algas, sendo que o padrão cromatográfico encontrado em cada classe foi discutido.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Milênio-Redoxom

Characteristic product ions of acetylene carotenoids by electrospray and nanospray ionization tandem mass spectrometry

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Astaxanthin Restrains Nitrative-Oxidative Peroxidation in Mitochondrial-Mimetic Liposomes: A Pre-Apoptosis Model

Astaxanthin (ASTA) is a ketocarotenoid found in many marine organisms and that affords many benefits to human health. ASTA is particularly effective against radical-mediated lipid peroxidation, and recent findings hypothesize a "mitochondrial-targeted" action of ASTA in cells. Therefore, we examined the protective effects of ASTA against lipid peroxidation in zwitterionic phosphatidylcholine liposomes (PCLs) and anionic phosphatidylcholine: phosphatidylglycerol liposomes (PCPGLs), at different pHs (6.2 to 8.0), which were challenged by oxidizing/nitrating conditions that mimic the regular and preapoptotic redox environment of active mitochondria. Pre-apoptotic conditions were created by oxidized/nitr(osyl) ated cytochrome c and resulted in the highest levels of lipoperoxidation in both PCL and PCPGLs (pH 7.4). ASTA was less protective at acidic conditions, especially in anionic PCPGLs. Our data demonstrated the ability of ASTA to hamper oxidative and nitrative events that lead to cytochrome c-peroxidase apoptosis and lipid peroxidation, although its efficiency changes with pH and lipid composition of membranes.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESPBPE fellowship)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (Bolsa Produtividade em Pesquisa, Nivel 2, CNPq, Brazil)Programa Iberoamericano de Ciencia y Tecnologia para el Desarollo (CYTEDRed iberoamericana para el estudio de nuevos carotenoides bioactivos como ingredientes de alimentos, Spain)Univ Sao Paulo IQUSP, Inst Quim, Dept Bioquim, BR-05508000 Sao Paulo, SP, BrazilUniv Cruzeiro Sul, ICAFE, BR-01506000 Sao Paulo, SP, BrazilSuperintendencia Policia Tecn Cient, BR-05507060 Sao Paulo, SP, BrazilLychnoflora Pesquisa & Dev Prod Nat LTDA, BR-14030090 Ribeirao Preto, SP, BrazilGrp Fleury, BR-04344070 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Exatas & Terra, UNIFESP, BR-09972270 Diadema, SP, BrazilUniv Sao Paulo IQUSP, Inst Quim, Dept Quim Fundamental, BR-05508000 Sao Paulo, SP, BrazilCSIC, IATA, Dept Ciencia Alimentos, Calle Catedrat Agustin Escardino 7, Paterna 46980, SpainUniv Fed Sao Paulo, Dept Ciencias Exatas & Terra, UNIFESP, BR-09972270 Diadema, SP, BrazilFAPESP: 017/06032-2CNPq: 304663/2015-8RIENCBI: 112RT0445Web of Scienc

Antioxidant activity and chemical composition of the non polar fraction of Gracilaria domingensis (Kützing) Sonder ex Dickie and Gracilaria birdiae (Plastino & Oliveira)

Gracilaria domingensis (Kützing) Sonder ex Dickie and Gracilaria birdiae (Plastino & Oliveira) (Gracilariales, Rhodophyta) are seaweeds that occur on the Brazilian coast. Based on their economic and pharmaceutical importance, we investigated the antioxidant activity of the methanolic, ethyl acetate and hexane extracts of both species. The hexane extracts display a high antioxidant activity and comparative analyses indicated G. birdiae as the most active species. Chemical investigation of these fractions showed several carotenoids and fatty acids, as well as cholesterol and sitosterol derivatives. HPLC-DAD analysis of G. birdiae showed violaxanthin (0.04 μg.mg-1 of dry material), antheraxanthin (5.31 μg.mg-1), aloxanthin (0.09 μg.mg-1), zeaxanthin (0.45 μg.mg-1) and β-carotene (0.37 μg.mg-1) as the major carotenoids. G. domingensis showed a similar carotenoid profile, however, with much lower concentration than G. birdiae. Gas chromatography coupled to mass spectrometry was used to determine other nonpolar compounds of these seaweeds. The main compounds detected in both studied species were the fatty acids 16:0; 18:1 Δ9; 20:3 Δ6,9,12, 20:4 Δ5,8,11,14. We found no specificity of compounds in either species. However, G. birdiae, presented higher contents of carotenoids and arachidonic acid than G. domingensis

A Fragmentation study of di-acidic mycosporine-like amino acids in electrospray and nanospray mass spectrometry

Two mycosporine (MAAs), containing an extra acid function, were analyzed by nanospray and electrospray ionization tandem mass spectrometry. In contrast to the previous studies it is demonstrated that no significant characteristic methyl radical loss occurred in positive mode. The fragmentation pathway in negative mode was also proposed in this work, along with theoretical calculations to characterize the site of protonation.No presente estudo, duas micosporinas (MAAs) contendo um segundo ácido carboxílico foram submetidas à fragmentação em eletrospray e nanospray em diferentes equipamentos. Em contraste com resultados anteriores, a eliminação de radical metila no modo positivo de análise foi um processo minoritário de fragmentação. Neste trabalho apresentamos também a via de fragmentação destas substâncias em modo negativo e cálculos teóricos para caracterizar os sítios de protonação.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Apolar Compounds in Seaweeds from Fernando de Noronha Archipelago (Northeastern Coast of Brazil)

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 n9; 18 : 2 Δ9,12; 20 : 4; 20 : 5. These fatty acids are commonly found in seaweeds present in warm regions. Thus, we found no specificity in the presence of a particular set of fatty acids and the studied species indicating that they are not useful as taxonomic indicators. However, they could be used in a comparative study with algae found in polluted area because many of the studied seaweeds are widespread and Fernando de Noronha has low human influence

Differential metabolic and biological profiles of Lychnophora ericoides mart. (Asteraceae) from different localities in the Brazilian "campos rupestres"

This paper reports HPLC-DAD-MS/MS and HPLC-ECD characterisation of secondary metabolite profiles of Lychnophora ericoides Mart. leaf extracts from different provenances and their cytotoxic and antioxidant properties. Leaf extracts from populations representing seven different locations were evaluated for antioxidant activity by the DPPH radical scavenging system and activity towards cellular growth in three tumor cell lines. The extracts were electrochemically analysed by HPLC-ECD and their main secondary metabolites were identified by HPLC-DAD-MS and HPLC-DAD-MS/MS. An amplified defensive secondary chemistry, together with maximal cytotoxic and antioxidant bioactivities, were found for plants collected at the interface between two types of forest. These findings furnish additional support for the hypothesis that plants occurring at the interface between two forests ecosystems might be stimulated to amplify their own production and storage of defensive secondary metabolites due to the greater number of environmental influences

EFFECT OF CHARGE GENERATION IN ESI SOURCE ON THE NEUTRAL AROMATIC ELIMINATION MECHANISM IN XANTHOPHYLLS

Carotenes and xanthophylls are natural pigments with high economic relevance in chemical, cosmetics, food and pharmaceutical industries. Systematic studies of carotenoid fragmentation pathways have demonstrated that the neutral elimination of aromatic ring from the polyene chain by electrocyclization reaction produced diagnostic ions to rapidly identify their presence in mixture. However, carotenes and xanthophylls also showed the ability to produce both protonated and radical molecular species, opening up multiple acid-base and/or redox fragmentation, which hamper carotenoids elucidation. Here we investigate the ionization and fragmentation of the radical/protonated and sodiated parent masses [M]+•/[M+H]+ and [M+Na]+ of two natural xanthophylls (canthaxanthin and fucoxanthin) and the synthetic apo-b-carotene using a Fourier-transform ion-cyclotron resonance mass spectrometer (FTICR MS). The MS/MS analysis showed that sodium adduct yielded better fragmentation of the diagnostic aromatic ring elimination in a simpler MS/MS spectra, whereas molecular ion and protonated molecule resulted in a multitude of fragments involving additional charge-remote fragmentations and direct cleavages of the conjugated π-system by retro-ene and vinyl-allyl reactions. The results suggested that Na+ promoted electrocyclic aromatic ring elimination by assisting the correct orbital conformation of the polyene chain, giving clearly fragments to the unambiguous determination of carotenoids in biological samples.     Keywords: carotenoids, xanthophylls, pericyclic rearrangement, electrocyclization, aromatic ring elimination, FTICR M