Antioxidant properties of four edible algae harvested in the Noto Peninsula, Japan

There are various marine algal products consumed as traditional food in the Noto Peninsula area, Japan. Water extract solution (WE) and ethanolic extract solution (EE) were prepared from three brown algae, Phaeophyceae Scytosiphon lomentaria (kayamo-nori, dried product), Papenfussiella kuromo (kuromo, fresh-raw product) and Nemacystus decipiens (mozuku, fresh-raw product), and one Rhodophyceae Porphyra sp. (nori, dried product). We also studied their phenol contents and antioxidant properties including (1) suppression of hemoglobin-induced linoleic acid peroxidation, (2) reducing power, (3) ferrous ion chelating, (4) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and (5) scavenging of superoxide anion radical-generated non-enzymatic system. WE contained phenolic compounds about 2.2-9.4 mg catechin equivalent (CE)/g dry sample and showed strong antioxidant activities, although the results were varied with the five test models. On the other hand, the antioxidant activities of EE were not detected or very low compared to the ones of WE.