• Ocean and Polar Research
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• 제29권2호
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• pp.187-191
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• 2007

In this study, antioxidant activities of acetone/dichloromethane and methanol extracts of Arctic seaweeds were investigated. The antioxidant properties of both extracts of arctic seaweed were evaluated using two different peroxynitrite tests, including scavenging power on authentic peroxynitrite and inhibitory activities on peroxynitrite generation from 3-morpholinosydnonimine (SIN-1) producing superoxide anion and nitric oxide simultaneously in vitro. At concentration of $10\;{\mu}g/ml$, the acetone/dichloromethane and methanol extracts of Odonthalia dentata exhibited 54.6 and 64.2% inhibition against peroxynitrite generation from SIN-1 while they exhibited 24.3 and 23.0% scavenging activities on authentic peroxynitrite, respectively. On the other hand, the acetone/dichloromethane extract of Polysiphonia stricta exhibited 61.8% inhibition only against the induced peroxynitrite from SIN-1. Furthermore, the crude extracts of Odonthalia dentata and Polysiphonia stricta were fractionated into n-hexane, 85% aq. MeOH, n-BuOH, and $H_2O$ fractions, successively, and only 85% aq. MeOH fraction exhibited the best inhibition.

• Ocean and Polar Research
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• 제31권2호
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• pp.213-218
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• 2009

We examined the intracellular antioxidative effects of 20 Arctic seaweed extracts in Raw 264.7 cells. Each seaweed species was subjected to extraction using acetone/dichloromethane and methanol, respectively, after which the extracts were combined and used as the test sample. The antioxidant ability of all 20 seaweeds extracts was evaluated using four different activity tests, including the degree of occurrence of intracellular reactive oxygen species (ROS), $ONOO^-$, and lipid peroxidation in Raw 264.7 cells, as well as the extent of oxidative damage of genomic DNA purified from Raw 264.7 cells. Crude extracts from Monostroma obscurum, Alaria esculnta, Laminaria digitata, Desmarestia aculeata, Chorda filum, Ptilota seriata, Phycidrys rubens, Devaleraea ramentacea and Palmaria palmata exhibited significant scavenging effects on the generation of intracellular ROS. Among them, Monostroma obscurum and Phycidrys rubens significantly inhibited membrane lipid peroxidation and DNA oxidation. Moreover, Phycidrys rubens exhibited scavenging effects on peroxynitrite generated from SIN-1.

• Molecular & Cellular Toxicology
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• 제5권2호
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• pp.120-125
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• 2009

Alaria esculenta is a brown seaweed found in the Arctic. This study investigated the protective effect of A. esculenta extract (AEE) against oxidant-mediated injury and its mode of action in RAW264.7 macrophages. The methyl thiazolyl tetrazolium (MTT) assay showed that $H_2O_2$ treatment reduced cell viability, whereas AEE protected cells from $H_2O_2$-mediated cytotoxicity in a dose-dependent manner. Because heme oxygenase-1 (HO-1) is known to protect cells against oxidative damage, we investigated the effect of AEE on HO-1 gene expression and HO enzyme activity. The protective effect of AEE against $H_2O_2$-induced injury was correlated with increased HO enzyme activity. AEE also induced HO-1 mRNA and protein expression, as determined RT-PCR and Western blotting, respectively. To characterize the mechanisms by which AEE induces HO-1 gene expression, we examined the effect of AEE on the nuclear translocation of NF-E2-related factor-2 (Nrf2) and Akt phosphorylation. AEE treatment activated upstream signaling for HO-1 gene expression, including the nuclear translocation of Nrf2 and Akt phosphorylation. Collectively, these results suggest that AEE has anti-oxidant activity that is mediated, at least in part, via the activation of Nrf2 and Akt and the subsequent induction of HO-1 gene expression.