Antioxidant activity of phenolic meroditerpenoids from marine algae

The overall 102, quenching rate constants k, for three meroditerpenoids from Mediterranean marine algae of the genus Cystoseira were measured using 1,4_dimethylnaphthalene 1,4-endoperoxide as a thermal source of 1O2 (1Dg). The most active of the compounds tested had a ko, value which is comparable with that of alfa-tocopherol. These metabolites also act as inhibitors of methyl linoleate peroxidation, while their O2 quenching activity is rather low, similar to alfa-tocopherol.