Comparison of extraction and transesterification methods on the determination of the fatty acid contents of three Brazilian seaweed species

Seaweeds are photosynthetic organisms important to their ecosystem and constitute a source of compounds with several different applications in the pharmaceutical, cosmetic and biotechnology industries, such as triacylglycerols, which can be converted to fatty acid methyl esters that make up biodiesel, an alternative source of fuel applied in economic important areas. This study evaluates the fatty acid profiles and concentrations of three Brazilian seaweed species, Hypnea musciformis (Wulfen) J.V. Lamouroux (Rhodophya), Sargassum cymosum C. Agardh (Heterokontophyta), and Ulva lactuca L. (Chlorophyta), comparing three extraction methods (Bligh & Dyer - B&D; AOAC Official Methods - AOM; and extraction with methanol and ultrasound - EMU) and two transesterification methods (7% BF3 in methanol - BF3; and 5% HCl in methanol - HCl). The fatty acid contents of the three species of seaweeds were significantly different when extracted and transesterified by the different methods. Moreover, the best method for one species was not the same for the other species. The best extraction and transesterification methods for H. musciformis, S. cymosum and U. lactuca were, respectively, AOM-HCl, B&D-BF3 and B&D-BF3/B&D-HCl. These results point to a matrix effect and the method used for the analysis of the fatty acid content of different organisms should be selected carefully

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

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Dichotomaria marginata (Rhodophyta) as a bioindicator for marine pollution: An overview about its metabolites and adsorbed pollutants

Macroalgae are considered bioindicators for marine pollution, because they have the ability to quickly react to changes in their environment. In consequence, macroalgae populations fluctuate, according to species characteristics and adaptive strategies. Their cell wall polysaccharides contain sulfate groups that are capable of retaining and accumulating heavy metals. In addition to traditional contaminants, emerging pollutants are being recognized in aquatic environments. Herein, emerging pollutants have been identified after being desorbed from the macroalga Dichotomaria marginata, collected from Fortaleza Beach, Ubatuba -SP, Brazil. Based on that algal polysaccharide networks have the potential of forming hydrogen bonds with polar compounds, it was hypothesized that these pollutants would be bound to sugar polymers. Compounds present in the D. marginata samples were identified using both gas and liquid chromatography/mass spectrometry (GC/MS and HPLC/MS), assisted by computational methods. It was possible to unequivocally identify 22 emerging contaminants with GC/MS, and 16 substances with HPLC/MS

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

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

Effects of a cyanobacterial extract containing-anatoxin-a(s) on the cardiac rhythm of Leurolestes circunvagans

This work presents the effects of an anatoxin-a(s)-containing extract on a cockroach semi-isolated heart preparation and the results supporting the extract s biological activity on acetylcholinesterase (purified from ell). The presence of the toxin in cyanobacterial strains Anabaena spiroides (ITEP-024, ITEP-025 and ITEP-026) isolated from the Tapacurá reservoir in Pernambuco, Brazil, was confirmed by means of liquid chromatography coupled to an ion-trap mass spectrometer. The anticholinesterase activity was assessed biochemically by the Ellman test and was confirmed by measuring the cockroach s heart rate. The concentration of the extract containing the tested anatoxin-a(s) (antx-a(s)) (10, 16 and 100 &#956;g.&#956;L-1) inhibited the eel acetylcholinesterase (AChE) by more than 90%. The cockroach cardiac frequency increased by a maximum of about 20% within 29 min after the addition of 2.5x10³ &#956;g of extract containing antxa (s).g-1 bw (n=9, p<0.05). Our results strongly indicate that antx-a(s) is capable of exerting biological effects on cockroach, indicating that more research might be conducted to determine its role in the environment, especially on insects

Preliminary data of antioxidant activity of green seaweeds (Ulvophyceae) from the Southwestern Atlantic and Antarctic Maritime islands

Background. Seaweeds must survive in highly competitive environments and thus develop defense strategies that may produce highly diversified antioxidant compounds. Goals. The main objective of this work was to assess the antioxidant activity of green seaweeds. Methods. Six species of ulvophycean chlorophytes were collected during spring/ summer, between the Antarctic (Monostroma hariotii, Protomonostroma rosulatum and Ulva hookeriana formerly as U. bulbosa) and the southwestern Atlantic Ocean (Gayralia brasiliensis, Protomonostroma undulatum and Ulvafasciata). They were then tested for their antioxidant activities using the 2.2-diphenyl-picrylhydrazyl (DPPH) radical scavenging method and by quantification of their phenolic (expressed as gallic acid equivalent GAE and carotenoid contents. Results. Among the evaluated species, P. rosulatum and U. hookeriana showed high antioxidant potential (77.9±2.8 and 53.1±15.0%, respectively) and high phenolic content (176±6.0 and 144.7±8.9 ?g GAE g-1, respectively). These species were collected on King George Island (South Shetland archipelago, around the Antarctic Peninsula) and their higher antioxidant potential may be associated with adaptation to the high incidence of UV rays in this region during summer. In general, tested seaweeds, mainly the samples collected in the Antarctic and Chilean Patagonia, showed higher values of phenolic (from 58.3±2.0 to 144.7±8.9 ?g GAE g-1) and carotenoid contents (from 23.4±0.2 to 51.5±0.1 ?g ?-carotene g-1). Conclusions. The presence and levels of these compounds suggest that the target seaweeds may have high antioxidant potential. Also the antioxidant activity could be associated with the occurrence area of the species instead of the order or taxonomic group to which they belong

Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design

In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18-26A degrees C; L, 74-162 mu mol photons m(-2) s(-1); N, 40-80 mu mol L-1; P, 8-16 mu mol L-1; and M, 1-5 nmol L-1. The optimal conditions, which resulted in a maximum growth rate of a parts per thousand yen6.4% d(-1) from 7 to 10 days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 2(5) full factorial design) to be L, 74 mu mol photons m(-2) s(-1); T, 26A degrees C; N, 80 mu mol L-1; P, 8 mu mol L-1; and M, 1 nmol L-1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5-7.0% d(-1). The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X (L), (alpha = 0.05). On the other hand, the only significant quadratic term (X (Q)) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R (adjusted) (2) = 0.9540).INCTRedoxomaINCT-RedoxomaFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP [09/54718-4]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq [143542/2008-7]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CAPESCape