Antioxidant activity of dulse (Palmaria palmata) extract evaluated in vitro

Palmaria palmata (dulse) is traditionally consumed as a snack food and garnish; but, little is known about its potential as a source of antioxidants. A I-butanol soluble fraction extracted from dulse exhibited (OH)-O-. scavenging activity EDTA (non-site and site specific activity) in a deoxyribose assay. EC50 concentrations of dulse extract to quench DPPH. and ABTS(.+) free radicals were 12.5 and 29.5 mg/ml. Dulse extract inhibited (p < 0.05) conjugated diene production in a linoleic acid emulsion at 24, 48 and 52 h, 38 degreesC and inhibited (p = 0.044) thiobarbituric acid reactive substances (TBARS) production at 52 h. One milligram dulse extract exhibited reducing activity = 9.68 mug L-ascorbic acid and total polyphenol content = 10.3 mug gallic acid; the dulse extract did not chelate transition metal ions. The antioxidant activity of the dulse extract was associated with aqueous/alcohol-soluble compounds characterized by phenolic functional groups with reducing activity. (C) 2004 Elsevier Ltd. All rights reserved.