A novel antioxidant, pyrogallol-6,6’-bieckol isolated from a brown alga, Ecklonia cava

Abstract

Ecklonia cava is used in Korea as a traditional medical material and also as a food additive. In this study, we evaluated its antioxidant activity, and isolated and identified its novel antioxidative compound, pyrogallol-6,6’-bieckol (PYB). From the ethyl acetate fraction of E.cava extract, PYB was isolated and purified via celite and silica column chromatography followed by RP-HPLC, and identified on the basis of LC-MS and NMR spectroscopy. The antioxidant activities of PYB were evaluated by several in vitro assays such as radical scavenging activities (DPPH, alkyl, hydroxyl, superoxide radical scavenging assays) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assays. The results showed that PYB evidenced strong radical scavenging activities on DPPH, alkyl, hydroxyl, and superoxide radicals (IC50; 0.4µg/mL for DPPH, IC50; 1.76µg/mL for alkyl, IC50; 39.54µg/mL for hydroxyl, IC50; 18.50µg/mL for superoxide radical, respectively). The radical scavenging activities of PYB were determined to be as effective as the commercial antioxidant agent, ascorbicacid. Furthermore, PYB effectively inhibited H2O2-induced DNA damage. These results indicated that PYB from E.cava might prove useful as a novel natural antioxidant agent in the food and pharmaceutical industries.