Radical-scavenging capacity of phenol fractions in the brown seaweed Ascophyllum nodosum: An electrochemical approach

In this article, the radical-scavenging capacity of phenol fractions extracted from the brown seaweed Ascophyllum nodosum was assessed using in parallel colorimetric methods (ABTS and DPPH) and electrochemistry (cyclic voltammetry). Results obtained by the three methods correlated in the case of global fractions, whereas only ABTS and DPPH correlated when activities were expressed on a phenol basis. The successive fractions separated by both their average molecular size and their polarity exhibited activities largely dependant on their phenol content, suggesting that phlorotannins are the main anti-oxidant molecules in hydro-alcoholic extracts of A. nodosum. In addition, phenol fractions of relative low molecular weight were clearly more active than others. This work opens new opportunities to better evaluate the radical-scavenging potential of phenol pools in algae using both bi-parametric fractionating and electrochemistry. (C) 2011 Elsevier B.V. All rights reserved.