Isolation and identification of new compound, 2,7″-phloroglucinol-6,6′-bieckol from brown algae, Ecklonia cava and its antioxidant effect

Brown algae, Ecklonia cava has been regarded as a useful material in the prevention or treatment of several human diseases in Jeju Island, Korea. In this study, we investigated its antioxidant activity, and isolated a new antioxidative compound, which was identified as 2,7″-phloroglucinol-6,6′-bieckol (PHB) on the basis of LC/MS, as well as 1H and 13C NMR spectroscopy results. The antioxidant activity of PHB was evaluated via several in vitro assays, such as radical scavenging activities using electron spin resonance spectrometry, intracellular reactive oxygen species scavenging activity, and DNA damage assays. PHB evidenced profound scavenging activities on DPPH, alkyl, hydroxyl, and superoxide radicals (IC50: 0.51, 2.07, 75.64 and 57.19 μM for DPPH, alkyl, hydroxyl and superoxide radicals, respectively). The antioxidant activity of PHB was higher than that of ascorbic acid. Furthermore, PHB effectively inhibited H2O2-induced DNA damage. The results of this study indicate that PHB may prove useful as a novel natural marine antioxidant.

► 2,7″-phloroglucinol-6,6′-bieckol (PHB) isolated from Ecklonia cava, a brown algae.
► PHB showed strong scavenging activities on DPPH, alkyl, hydroxyl, and superoxide radicals.
► The antioxidant activities of PHB were higher than that of the commercial antioxidant, ascorbic acid.
► PHB effectively inhibited DNA damage induced by H2O2.
► PHB can be used for valuable natural antioxidant and seemed to be applicable in both healthy medicine and food industry.