Brown and red seaweeds as potential sources of antioxidant nutraceuticals

摘要

Multifunctional antioxidant potential of several brown and red edible seaweeds was evaluated in organic and aqueous soluble extracts. The great reduction power and radical scavenging activity of Bifurcaria bifurcata - a Sargassaceae brown algal species - in both organic and aqueous extracts were emphasized. In addition, two Gigartinaceae red algal species, Gigartina pistillata and Mastocarpus stellatus showed relatively high reduction power in the aqueous extracts. When all of the variables of the aqueous extracts were combined in a principal component analysis, a clear differentiation pattern among the tested seaweeds was observed. In the Phaeophyceae, the correlation found among reduction power, radical scavenging activity and total phenolic content is in favour of the involvement of phenolic compounds in the antioxidant mechanisms, whereas in the case of the Florideophyceae, the role of sulphate-containing polysaccharides in reduction power is presumably shown. Nevertheless, the evidence of some taxonomy-based clustering (class and order levels) in this study may prove that polyphenol and sulphate content, besides multifunctional antioxidant profile, are related to specific groups of seaweeds. This evidence could help the search of suitable sources of phytochemicals from seaweeds for further nutraceutical applications.