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Phytosterols profile of edible macroalgae
G. Lopes 1 , C. Sousa 1 , J. Bernardo 1 , T. Mouga 2 , P. Valentão 1 , P. B. Andrade 1
1 REQUIMTE/Department of Pharmacognosy, Faculty of Pharmacy, University of Oporto, Oporto,
Portugal.
2 Escola Superior de Turismo e Tecnologia do Mar, Instituto Politécnico de Leiria, Santuário N.ª Sra.
Dos Remédios, Apartado 126, 2524-909 Peniche, Portugal.
Macroalgae are eukaryotic photosynthesizing multicellular organisms responsible for half of
the O2 production among the major primary producers. They have shown to constitute a rich
source of bioactive compounds, being used as food and in industry. The investigation of new
algal chemical compounds is also a promising area in pharmaceutical studies.
Eighteen seaweeds from the Portuguese coast (3 Chlorophyta, 5 Rhodophyta and 10
Phaeophyta species) were subjected to alkaline hydrolysis and studied for their phytosterols
profile. Seven compounds were determined by HPLC-DAD (Fig. 1).
Fig. 1. HPLC-DAD chromatogram of the brown algae Padina pavonica (detection at 205nm). Peaks:
desmosterol (1), ergosterol (2), fucosterol (3), cholesterol (4), stigmasterol + campesterol (5), βsitosterol
(6).
Method repeatability was good (1.7% variation coefficient for cholesterol), linearity was
excellent for the examined fortification range, with 92% recovery for cholesterol.
Fucosterol was the predominant phytosterol in Phaeophyta and Chlorophyta (71-95% of total
sterols determined), and cholesterol the main one in Rhodophyta (34-87% of total sterol
content). The presence of fucosterol at low concentrations in Rhodophyta is characteristic of
this phylum. From the studied algae, Asparagopsis armata contained the lowest amounts of
phytosterols (555 mg/Kg dry weight) and Cystoseira tamariscifolia the highest one (6502
mg/Kg dry weight).
Acknowledgements:
G. Lopes (SFRH/BD/61565/2009) and J. Bernardo (BII) are indebted to Fundação para a Ciência e a
Tecnologia (FCT) for their grants.
10 3 rd meeting of young researchers at UP