Reduction of lipid peroxidation and H2O2-mediated DNA damage by a red alga (Grateloupia filicina) methanolic extract

The antioxidant activity of an extract of Grateloupia filicina was evaluated using linoleic acid and fish oil as substrates in an induct period at 65 degrees C. Furthermore, the algal extract was subjected to comet assay to evaluate its protecting ability for H2O2-induced DNA damage in rat lymphocytes. Progression of oxidation was examined using weight gain, peroxide value (PV), 2-thiobarbituric acid reactive substances and conjugated diene data. Effectiveness of the extract at 0.03 and 0.05% levels was superior to that of a-tocopherol at 0.01% and the activity of 0.05% extract was higher than that of butylated hydroxyanisole and butylated hydroxytoluene at 0.01%. Also, the algal extract significantly inhibited H2O2 induced DNA damage in comet assay. The maximum DNA damage inhibition (68.9%) was recorded from the 50 mu g ml(-1) alga extract when the rat lymphocyte cells were treated with 50 mu M H2O2. (c) 2005 Society of Chemical Industry.