Free radical scavenging activity of enzymatic extracts from a brown seaweed Scytosiphon lomentaria by electron spin resonance spectrometry

The radical scavenging activities of the enzymatic extracts hydrolyzed from Scytosiphon lomentaria on hydroxyl, alkyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were investigated using a spin-trapping electron spin resonance (ESR) spectrophotometer and compared with the ESR signal intensity. The brown seaweed S. lomentaria was enzymatically hydrolyzed to prepare water-soluble extracts by five carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and five proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase, Protamex). The enzymatic extracts exhibited strong scavenging activity on hydroxyl, alkyl and DPPH radical, and the activity increased with increment of concentration of the enzymatic extracts. These results were similar to the scavenging values on hydroxyl and alkyl radical, and lower to the scavenging value on DPPH radical compared with vitamin C used as a reference, respectively. Therefore, the enzymatic extracts of S. lomentaria are a potent antioxidant. (C) 2003 Elsevier Ltd. All rights reserved.