title: Identification of chemical structure and free radical scavenging activity of diphlorethohydroxycarmalol isolated from a brown alga, Ishige okamurae.
abstract: To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative activity of methanolic extracts from the marine brown alga, Ishige okamurae collected off Jeju Island. A potent free radical scavenging activity was detected in the ethyl acetate fraction containing polyphenolic compounds, and the potent antioxidant elucidated as a kind of phlorotannin, diphlorethohydroxycarmalol, by NMR and mass spectroscopic data. The free radical scavenging activities of the diphlorethohydroxycarmalol were investigated in relation to 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals using an electron spin resonance (ESR) system. The diphlorethohydroxycarmalol was found to scavenge DPPH (IC50=3.41 microM) and alkyl (IC50=4.92 microM) radicals more effectively than the commercial antioxidant, ascorbic acid. Therefore, these results present diphlorethohydroxycarmalol as a new phlorotannin with a potent antioxidative activity that could be useful in cosmetics, foods, and pharmaceuticals.
authors.affiliation: Faculty of Applied Marine Science, Cheju National University, Jeju 690-756, Korea.
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Heo
authors.forename: Jong-Pyung
authors.initials: JP
authors.lastname: Kim
authors.forename: Won-Kyo
authors.initials: WK
authors.lastname: Jung
authors.forename: Nam-Ho
authors.initials: NH
authors.lastname: Lee
authors.forename: Hahk-Soo
authors.initials: HS
authors.lastname: Kang
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Jun
authors.forename: Soon-Hye
authors.initials: SH
authors.lastname: Park
authors.forename: Sung-Myung
authors.initials: SM
authors.lastname: Kang
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: Lee
authors.forename: Pyo-Jam
authors.initials: PJ
authors.lastname: Park
authors.forename: You-Jin
authors.initials: YJ
authors.lastname: Jeon
mesh_terms: D001713:Biphenyl Compounds; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000459:Phaeophyceae / Q000737:chemistry / Q000378:metabolism*; D010851:Picrates / Q000032:analysis; D012623:Seawater
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006575:Heterocyclic Compounds, 3-Ring; D010851:Picrates; C513811:diphlorethohydroxycarmalol; C004931:1,1-diphenyl-2-picrylhydrazyl