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Validation of a spectrophotometric methodology for a rapid iodine analysis in algae and seaweed casts
Publication . Nunes, N.; Valente, S.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M.A.A. Pinheiro de
Iodine plays an important role in human metabolism and its deficiency is particularly harmful in pregnancy and childhood. It remains a major public health concern
in many countries, especially in Portugal. The main purpose of this work was to develop a validated spectrophotometric analysis for a fast and reliable iodine
quantification in algal samples. Absorbance was determined at 410 nm demonstrating a good linearity (R2 ≈ 1.0) in the range of 0–0.06 mg I/100 g. LOD and LOQ
were 1.7 × 10−3 and 5.0 × 10−3 mg I/100 g, respectively. Accuracy was determined using recovery and varied between 101 and 118%. For precision analysis, an
intra-day test performance (RSD = 8.7%) and a repeatability assay (RSD = 3.8%) were performed. Matrix effect assessment demonstrated that this had a negligible
effect (3.2%) in the iodine quantification. The spectrophotometric method was externally validated, for iodine quantification in algal samples, by INSA certified
laboratory. The correlation coefficient between external iodine quantification and our work was R2 ≈ 0.9, showing a good correlation. Applicability was assessed in
25 macroalgae species (5 green, 9 red and 11 brown), 12 seaweed casts, collected in Canary Islands and 1 microalga (Isochrysis galbana) provided by ITC (Instituto
Tecnologico de Canarias).
Fatty acid composition, TLC screening, ATR-FTIR analysis, anti-cholinesterase activity, and in vitro cytotoxicity to A549 tumor cell line of extracts of 3 macroalgae collected in Madeira
Publication . Nunes, N.; Rosa, G. P.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M. A. A. Pinheiro de
Three macroalgae collected at Madeira Island were included in this study to determine their potential for drug, nutraceutical,
food, or supplement application. Fatty acid content was higher in Zonaria tournefortii (12.32 mg g−1 dw) with 16.58% of PUFAs,
eicosapentaenoic acid (C20:5ω3), and arachidonic acid (20:4ω6) having concentrations of 2.59 and 1.17%, respectively. The
anti-thrombogenic and anti-atherogenicity potential was higher for Z. tournefortii due to relevant fatty acids in the biochemical
composition this macroalgae. Lipid classes were assessed in the lipid extract and neutral lipids (NL) were in higher yield in
Asparagopsis taxiformis (51.16%) and lower in Z. tournefortii (26.96%). The glycolipids (GL) were between 36.03 and 16.11%
in Z. tournefortii and Ulva lactuca. Phospholipids (PL) fraction varied from 35.91 and 31.60% in A. taxiformis and
Z. tournefortii. TLC screening identified that U. lactuca contains phytol and cholesterol in its NL, digalactosyldiacylglycerol
in its GL, and cardiolipin and L-α-phosphatidylcholine in its PL. Zonaria tournefortii contains phytol and cholesterol in its NL
classes, and the PL classes contain L-α-phosphatidylethanolamine and 1-(3-sn-phosphatidyl)-rac-glycerol. The macroalgae
A. taxiformis revealed cholesterol in its NL fraction and the same phospholipids as Z. tournefortii in its PL fraction. ATRFTIR analysis enabled a “fingerprint” spectra and important sulfation absorption bands were identified, revealing the functional
polysaccharides within these macroalgae. Anti-cholinesterasic activity was assessed in A. taxiformis, with a low IC50 for AChE
(8.92 ± 0.43 μg mL−1
) and BuChE (13.96 ± 0.32 μg mL−1
), demonstrating dual inhibitory activity, justifying the interest to
identify the active principle which may be the scaffold of a novel drug.
Evaluation of fucoxanthin contents in seaweed biomass by vortex-assisted solid-liquid microextraction using high-performance liquid chromatography with photodiode array detection
Publication . Nunes, N.; Leça, João M.; Pereira, Ana C.; Pereira, Vanda; Ferraz, S.; Barreto, Maria Carmo; Marques, José C.; Carvalho, M.A.A. Pinheiro de
Fucoxanthin is considered an important marine bioactive compound with biological properties with promising effects, namely on health. A simple and efficient
analytical methodology is proposed for its quantification in seaweed biomass by using vortex-assisted solid-liquid microextraction (VASLME) followed by reversed
phase high-performance liquid chromatography (RP-HPLC) photodiode array detection (PDA) analysis. This microextraction uses reduced quantities of sample
(25 mg) and solvent (300 μL of ethanol) to efficiently extract this high-valued xanthophyll, in a vortex time of 15 min. These extraction parameters were optimized
performing a Central Composite Design (CCD) analysis, running 32 individual experiments. In turn, the method validation was assessed. The linearity of the method
was confirmed (R2 = 0.99998) in a concentration range from 12 to 3600 μg·g−1 dw. Also, good sensitivity and accuracy results were observed through the LOD
(3.33 μg·g−1
), LOQ (10.09 μg·g−1
) and recovery (varied from 95 to 97%) assessments. Good precision was also verified, with intra-day variation within 2.0–3.3%,
and inter-day within 1.0–3.8%. Matrix effect was also evaluated and an acceptable variation of 3.4% was found. The method applicability was confirmed by the
analysis of 22 seaweed biomass samples and fucoxanthin content was found to vary from about 10 to 853 μg·g−1 dw. This method demonstrated a good performance
and can be successfully implemented for a rapid, reliable and accurate screening of fucoxanthin in seaweed biomass.
Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure
Publication . Sangil, Carlos; Martins, Gustavo M.; Hernández, José Carlos; Alves, Filipe; Neto, Ana I.; Ribeiro, Cláudia; León-Cisneros, Karla; Canning-Clode, João; Rosas-Alquicira, Edgar; Mendoza, José Carlos; Titley, Ian; Wallenstein, Francisco; Couto, Ruben P.; Kaufmann, Manfred
Shallow subtidal macroalgal communities in the North-eastern Atlantic archipelagos (Azores, Madeira, Canaries and Cape
Verde) were studied in order to identify their spatial organization patterns and the main drivers of change. Fifteen islands and
145 sites across 15º of latitude and 2850 km were sampled. We found high spatial variability across the scales considered
(archipelago, island and site). The structure of macroalgal communities differed among archipelagos, except between Madeira
and the Canaries, which were similar. Across a latitudinal gradient, macroalgal communities in the Azores were clearly separated
from the other archipelagos; communities in Madeira and the Canaries occupied an intermediate position, while those in Cape
Verde appeared at the opposite end of the gradient. In the Azores, species with warm-temperate affinities dominated commu nities. Cape Verde communities were, in contrast, dominated by tropical taxa, whereas in the subtropical Canaries and Madeira
there was a mixture of species with colder and warmer affinities. Apart from crustose coralline algae, the Dictyotales were the
group with greatest cover; larger and longer-lived species were progressively replaced by short-lived species along a latitudinal
gradient from north to south. The perennial species Zonaria tournefortii dominated the sea-bottom in the Azores, the semi perennial Lophophora variegata in the Canaries, the filamentous algae in Madeira and the ephemeral Dictyota dichotoma in Cape
Verde. We hypothesized that the differences among archipelagos could be explained by synergies between temperature and
herbivory, which increased in diversity southwards, especially in Cape Verde. This was supported by the predominance of non crustose macroalgae in the Azores and of crustose macroalgae in Cape Verde, as would be predicted from the greater herbivore
activity. At the scale of islands and sites, the same set of environmental variables drove differences in macroalgal community
structure across all the Macaronesian archipelagos.
Lipophilic toxins occurrence in non-traditional invertebrate vectors from North Atlantic Waters (Azores, Madeira, and Morocco): Update on geographical tendencies and new challenges for monitoring routines
Publication . Silva, Marisa; Rodríguez, Inés; Barreiro, Aldo; Kaufmann, Manfred; Neto, Ana Isabel; Hassouani, Meryem; Sabour, Brahim; Alfonso, Amparo; Botana, Luis M.; Vasconcelos, Vitor
In the last decades, due to monitoring programs and strict legislation poisoning incidents occurrence provoked
by ingestion of naturally contaminated marine organisms has decreased. However, climate change and an thropogenic interference contributed to the expansion and establishment of toxic alien species to more temperate
ecosystems. In this work, the coasts of Madeira, São Miguel islands and the northwestern Moroccan coast were
surveyed for four groups of lipophilic toxins (yessotoxins, azaspiracids, pectenotoxins, and spirolides), searching
for new vectors and geographical tendencies. Twenty-four species benthic organisms were screened using
UHPLC-MS/MS technique. We report 19 new vectors for these toxins, six of them with commercial interest (P.
aspera, P. ordinaria, C. lampas, P. pollicipes, H. tuberculata and P. lividus). Regarding toxin uptake a south-north
gradient was detected. This study contributes to the update of monitoring routines and legislation policies,
comprising a wider range of vectors, to better serve consumers and ecosystems preservation.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
5876
Funding Award Number
UID/BIA/00329/2013