Potential antioxidant activity of marine red alga Grateloupia filicina extracts

Grateloupia filicina is an important alga cultivated as a source of food in Korea and Japan. In order to examine its potential antioxidant activity, crude extracts of G. filicina were evaluated for their effect on scavenging of reactive oxygen species (DPPH, .OH, H2O2, and O-2(-)) and inhibition of lipid peroxidation. The activities of these extracts were compared with those of commercial antioxidants such as BHA, BHT and alpha-tocopherol. The methanolic extract (2 mg/mL) of G. filicina scavenged 82% of DPPH radicals which is almost three times higher than that of BHT. The same methanolic extract scavenged 65% of superoxide anion which is almost two times higher than that of BHT and alpha-tocopherol. In contrast, the extracts in chloroform and carbon tetrachloride inhibited lipid peroxidation more effectively than all commercial antioxidants tested in a linoleic acid model system.