Identification of chemical structure and free radical scavenging activity of diphlorethohydroxycarmalol isolated from a brown alga, Ishige okamurae.
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.
Heo
Soo-Jin
SJ
Faculty of Applied Marine Science, Cheju National University, Jeju 690-756, Korea.
Kim
Jong-Pyung
JP
Jung
Won-Kyo
WK
Lee
Nam-Ho
NH
Kang
Hahk-Soo
HS
Jun
Eun-Mi
EM
Park
Soon-Hye
SH
Kang
Sung-Myung
SM
Lee
Young-Jae
YJ
Park
Pyo-Jam
PJ
Jeon
You-Jin
YJ
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
D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006575:Heterocyclic Compounds, 3-Ring; D010851:Picrates; C513811:diphlorethohydroxycarmalol; C004931:1,1-diphenyl-2-picrylhydrazyl