Antioxidant activity of phenolic meroditerpenoids from marine algae

The overall 1O2 quenching rate constants k(q) 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 (1?(g)). The most active of the compounds tested had a k(q), value which is comparable with that of ?-tocopherol. These metabolites also act as inhibitors of methyl linoleate peroxidation, while their O2.- quenching activity is rather low, similar to ?-tocopherol.