Radical scavenging activity of lipids from seaweeds isolated by solid-liquid extraction and supercritical fluids

In vitro antioxidant activities of the lipid fractions from two selected seaweeds, Solieria chordalis and Sargassum muticum were investigated according to the extraction methods. The activity of neutral lipids, glycolipids and phospholipids, thanks to extraction by chloroform/methanol (1/1 v/v; CM) mixture, pure supercritical carbon dioxide (sc-CO2), supercritical carbon dioxide with 2% of ethanol (sc-CO2 + EtOH 2%) and supercritical carbon dioxide with 8% of ethanol as co-solvent (sc-CO2 + EtOH 8%), were studied using DPPH radical scavenging assays. All the lipid classes demonstrated a free radical scavenging activity at the concentration of 1 mg/ml. The best scavenging activity (86.6 ± 5.7%) was obtained when the neutral lipid fraction was extracted from S. chordalis with a CM mixture. The neutral lipid fraction extracted with sc-CO2 showed a lower activity than those obtained with solvents. However, the addition of ethanol in sc-CO2 did not affect the antioxidant activity of neutral lipids fixed at around 16% of radical scavenging. For S. muticum, the activity of glycolipids (50.9 ± 0.8%) and phospholipids (48.4 ± 1.6%) obtained with sc-CO2 were twice as large as that of fractions obtained with CM, 29.6 ± 3.4% and 28.0 ± 4.2%, respectively. The activity of neutral lipids did not change with the extraction method with around 25% of radical scavenging. This is the first report of free radical scavenging activity of lipid classes obtained by supercritical carbon dioxide extraction from seaweeds.