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 dependent on their phenol content, suggesting that phlorotannins are the main anti-oxidant molecules in hydro-alcoholic extracts of A.

Phenolic compounds in the brown seaweed Ascophyllum nodosum: distribution and radical-scavenging activities.

Introduction: Phenolic compounds are metabolites exhibited at high levels in Phaeophyceae. Although several studies have been conducted on total phenol contents, no one to our knowledge has dealt with the contents of phenolic compounds and antioxidant activities on purified fractions.

Objective: The purpose of this study was the extraction and purification of phenolic compounds from the brown seaweed Ascophylllum nodosum, to determine both their distribution and their radical-scavenging activities, and to obtain a sufficiently purified oligophenolic fraction to perform an RP-HPLC analysis on molecules with a molecular weight (MW) < 2 kDa.