Isolation and identification of a novel antioxidant from marine algae and its antioxidative effect

Abstract

To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative effect of a marine alga, Ecklonia cava using several biological assays. A potent free radical scavenging activity was detected in the diethyl ether fraction, and the active compound was isolated via silca column chromatography followed by RP-HPLC. Finally, the novel antioxidant was identified on the basis of LC-MS and NMR spectroscopic data as 2,7”-phloroglucinol-6,6’-bieckol (PB), a kind of phlorotannin. The antioxidant activities of PB 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 PB evidenced strong radical scavenging activities on DPPH, alkyl, hydroxyl, and superoxide radicals then that of commercial antioxidant agent, ascorbic acid. Furthermore, PB effectively inhibited H2O2-induced DNA damage. These results indicated that PB from E. cava might prove useful as a novel natural antioxidant agent in the food and pharmaceutical industries.