Total phenolic contents, radical scavenging and cyclic voltammetry of seaweeds from Brittany

► The different seaweed species from Brittany possess diverse antioxidant properties. ► The type of extracts has a great impact on TPC and antioxidant seaweed's activity. ► Ascophyllum nodosum is the most reactive than Fucus serratus than Fucus vesiculosus. ► Good correlation between spectroscopic methods and electrochemical methods for algae. ► Cyclic voltammograms of a number of polyphenols and the study of their properties.