Antioxidant Effects of Phlorotannins Isolated from Ishige okamurae in Free Radical Mediated Oxidative Systems

Abstract

Three phlorotannins, including phloroglucinol, diphlorethohydroxycarmalol, and 6,6'-bieckol, were isolated from Ishige okamurae by column chromatography. The structures of the phlorotannins were determined on the basis of spectroscopic analysis, including NMR and mass spectrometry (MS) techniques. Antioxidant effects of phlorotannins were measured by direct free radical scavenging activities using the electron spin resonance spectrometry (ESR) technique and cellular systems in vitro. The results indicated that diphlorethohydroxycarmalol and 6,6'-bieckol showed potential radical scavenging activities against the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, alkyl, and superoxide radicals. Moreover, no cytotoxicities of the phlorotannins on human fetal lung fibroblasts cell line (MRC-5), mouse macrophages cell line (RAW264.7), and human leukemic cell line (HL-60) were observed. In addition, diphlorethohydroxycarmalol and 6,6'-bieckol significantly reduced the intracellular reactive oxygen species level assessed by 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay in RAW264.7 cells, and myeloperoxide (MPO) activity in HL-60 cells and radical-mediated oxidation of cell membrane proteins in RAW264.7 cells were dose-dependently inhibited in the presence of diphlorethohydroxycarmalol and 6,6'-bieckol. In conclusion, these results suggested that phlorotannins could be used as novel functional foodstuffs or antioxidants in the cosmetic and drug industries.

Depressive Effects on the Central Nervous System and Underlying Mechanism of the Enzymatic Extract and Its Phlorotannin-Rich Fraction fromEcklonia cavaEdible Brown Seaweed

“…30) EC phlorotannin contains such phenolic secondary metabolites as eckol, 6,6 0 -bieckol, dieckol, phlorofucofuroeckol, and triphlorethol-A. 23,24) It has been reported that phlorotannins have such biological properties as antioxidative, 31) anti-inflammatory, 32) antibacterial, 33) antiallergic, 34) and -glucosidase inhibitory 35) effects. To investigate whether the marine polyphenol, phlorotannin, had the same depressive effect on CNS as terrestrial polyphenols, we evaluated the anticonvulsive and sleep-inducing effects of PTRF fractionated from ECEE.…”

<i>In Vivo</i> Antioxidant Activity of Fucoxanthin on Obese/Diabetes KK-<i>A<sup>y</sup></i> Mice

“…Antioxidant activity of seaweed polyphenols have been reported by many researchers [3][4][5][6]. However, the evaluation of the effects exerted by algal polyphenols gives several problems when moving from in vitro experimental systems to the complexity of in vivo system.…”

Arousal Inhibitory Effect of Phlorotannins on Caffeine in Pentobarbital-Induced Mice

“…Their sensory characteristics would be suitable as an additive to coffee. In addition, phlorotannins have various biological activities, such as antioxidative (Zou et al, 2008), anti-inflammatory , antibacterial , and antiallergic (Sugiura et al, 2006) effects. Therefore, HP-PRT may be a good additive for the preparation of coffee products without an arousal effect.…”