• Journal of Life Science
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• v.28 no.10
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• pp.1170-1178
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• 2018

The anti-inflammatory effect of brown alga Ecklonia cava is well known, and several phlorotannins have also been reported. In this study, major active components for anti-allergy and anti-inflammation were identified by NMR and MS analysis, and the levels of effectiveness were compared. Six major phlorotannins-phloroglucinol, eckol, eckstolonol, triphlorethol-A, phlorofucofuroeckol A, and dieckol-were isolated from the ethyl acetate fraction of E. cava. In order to analyze the major active substances in E. cava, antioxidant, anti-inflammatory, and anti-allergic effects were evaluated for the six separate substances. Antioxidant capacities of each phlorotannin were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, where phlorofucofuroeckol A and triphlorethol-A had the highest radical scavenging capacity in respective radical scavenging assays. Phlorofucofuroeckol A exhibited the highest inhibition of nitric oxide production in LPS-stimulated RAW 264.7 cells among phlorotannins tested. Dieckol inhibited the release of ${\beta}-hexosaminidase$, a marker for the release of histamine in mast cells, in a dose-dependent manner in antigen-stimulated RBL-2H3 mast cells. Additionally, no cytotoxicities were observed at 1 and $2{\mu}g/ml$ in both phlorofucofuroeckol A and dieckol. These results suggest that phlorofucofuroeckol A and dieckol may play a key role in allergic inflammatory reactions.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.198-204
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• 2011

The brown seaweed Ecklonia cava is known to be a rich source of phlorotannins that have diverse biological activities. Among the phlorotannins in E. cava, concentrations of dieckol and phlorofucofuroeckol-A, which were identified as major active components, were determined in different parts of the tissue. We compared the efficacy of different pretreatments for their extraction. A high-performance liquid chromatography (HPLC) method to determine phlorotannin concentrations showed good accuracy (92.64 and 94.02%, respectively), precision (3.92 and 3.94%, respectively), and linearity (r>0.996). Mature thalli contained 1.5-fold more dieckol (1.82 mg/g-dry tissue) than young thalli. In the tissues of E. cava, blade tissue contained more phlorotannins than the stipe or holdfast. Among differently dried thalli, approximately 90% or more dieckol and phlorofucofuroeckol-A were extracted from shadow-dried tissue as compared with lyophilized tissue. In sun-dried and oven-dried thalli, approximately 60% of the phlorotannins were extracted. Thalli washed with fresh water, boiled thalli, and steamed thalli showed reduced extraction of the compounds.

• Archives of Pharmacal Research
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• v.28 no.6
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• pp.691-698
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• 2005

Phlorotannins, the polyphonic compounds found in brown Eisenia and Ecklonia algae, have several pharmacologically beneficial effects such as anti-inflammation. In addition, our recent data show that these compounds may improve the cognitive functions of aged humans suggesting the potential ability to enhance memory in several neurodegenerative disorders. To examine the experimental hypothesis that two effective components of Ecklonia cava, dieckol and phlorofucofuroeckol (PFF), have memory-enhancing abilities, both were administered orally to mice before a passive avoidance test. The repeated administration of either dieckol or PFF dose-dependently reduced the inhibition of latency by the administration of ethanol. To investigate the mode of memory-enhancing actions, the levels of major central neurotransmitters in three different regions (striatum, hippocampus, and frontal cortex) of the mouse brain were measured. The levels of some of the neurotransmitters were significantly changed by ethanol. Both dieckol and PFF altered the levels of some neurotransmitters modified by the ethanol treatment. It is noteworthy that both dieckol and PFF increased the level of acetylcho-line, and they exerted anticholinesterase activities. Overall, the memory-enhancing abilities of dieckol and PFF may result from, at least in part, the increment of the brain level of acetylcho-line by inhibiting acetylcholinesterase.

• ALGAE
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• v.30 no.4
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• pp.313-323
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• 2015

Lipid peroxidation means the oxidative degradation of lipids. The process from the cell membrane lipids in an organism is generated by free radicals, and result in cell damage. Phlorotannins, well-known marine brown algal polyphenols, have been utilized in functional food supplements as well as in medicine supplements to serve a variety of purposes. In this study, we assessed the potential anti-lipid peroxidation activity of phlorofucofuroeckol-A (PFF-A), one of the phlorotannins, isolated from Ecklonia cava by centrifugal partition chromatography in 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH)-stimulated Vero cells and zebrafish system. PFF-A showed the strongest scavenging activity against alkyl radicals of all other reactive oxygen species (ROS) and exhibited a strong protective effect against ROS and a significantly strong inhibited of malondialdehyde in AAPH-stimulated Vero cells. The apoptotic bodies and pro-apoptotic proteins Bax and caspase-3, which were induced by AAPH, were strongly inhibited by PFF-A in a dose-dependent manner and expression of Bcl-xL, an anti-apoptotic protein, was induced. In the AAPH-stimulated zebrafish model, additionally PFF-A significantly inhibited ROS and cell death, as well as exhibited a strong protective effect against lipid peroxidation. Therefore, these results suggest that PFF-A has excellent protective effects against ROS and lipid peroxidation induced by AAPH in both an in vitro Vero cell model and an in vivo zebrafish model.

• ALGAE
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• v.30 no.3
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• pp.241-246
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• 2015

This research was conducted to develop effective and safe marine-derived antiviral compounds against norovirus. The ethyl acetate (EtOAc)-extract from Eisenia bicyclis exhibited strong antiviral activity against murine norovirus (MNV) as a norovirus surrogate. Among the phlorotannins from E. bicyclis, dieckol (DE) and phlorofucofuroeckol-A (PFF) were known to possess the strongest antibacterial activity. In this study, DE and PFF were evaluated for antiviral activity against MNV. DE and PFF exhibited strong anti-MNV activity with 50% effective concentration ($EC_{50}$) of $0.9{\mu}M$. However, PFF exhibited more effective antiviral activity against MNV with higher selective index (668.87) than that of DE (550.60), due to its lower cell toxicity against RAW 264.7. This is the first report on the anti-MNV activity of phlorotannins from seaweed. The results obtained in this study suggest that the phlorotannins could be used as a potential source of natural antiviral agents.

• Food Science and Industry
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• v.51 no.4
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• pp.334-342
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• 2018

People in Korea, a peninsular, have acquired a variety of marine food resources including seaweeds. Ecklonia stolonifera, a brown algae, is commonly dwelling in Korean coasts and their cultivation methods were developed for a mass-production. Recently, studies have revealed that Ecklonia stolonifera is a promising material for the development of health functional foods. In an effort to carefully review the current understating in the effects and mechanisms of Ecklonia stolonifera on liver functions by deduction from relevant literatures, the effective components were identified as phlorotannins, including dieckol, eckstolonol, eckol, phlorofucofuroeckol A, and phlorosterol. Their aiding action on the hepatic functions is categorized as follows. A) Regulation of oxidative stress by anti-oxidant capacity, B) Protection of hepatocytes from toxins, C) Prevention of alcoholic fatty liver and fibrogenesis, D) Regulation of chronic disease by improvement of inflammatory responses and lipid metabolisms, and E) indirect benefit conferred by a personal total wellness.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1376-1380
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• 2005

In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with $EC_{50}$ values of 62.0 and 79.2 $\mu$g/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an $EC_{50}$ value of 50.0 $\mu$g/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.194-198
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• 2004

Reactive oxygen species (ROS) play an important role in the pathogenesis of many human degenerative diseases such as cancer, aging, arteriosclerosis, and rheumatism. Much attention has been focused on the development of safe and effective antioxidants. To discover sources of antioxidative activity in marine algae, extracts from 17 kinds of seaweed were screened for their inhibitory effect on total ROS generation in kidney homogenate using 2',7'-dichlorofluorescein diacetate (DCFH-DA). ROS inhibition was seen in three species: UIva pertusa, Symphyocladia latiuscula, and Ecklonia stolonifera. At a final concentration of 25 $\mu\textrm{g}$/mL, U. pertusa inhibited 85.65$\pm$20.28％ of total ROS generation, S. latiscula caused 50.63$\pm$0.09％ inhibitory, and the Ecklonia species was 44.30$\pm$7.33％ inhibition. E. stolonifera OKAMURA (Lam-inariaceae), which belongs to the brown algae, has been further investigated because it is commonly used as a foodstuff in Korea. Five compounds, phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5), isolated from the ethyl acetate soluble fraction of the methanolic extrclct of E. stolonifera inhibited total ROS generation.

• ALGAE
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• v.29 no.2
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• pp.165-174
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• 2014

Ecklonia cava is a common edible brown algae that is plentiful in Jeju Island of Republic of Korea. Polyphenols from E. cava have strong anti-inflammatory activity. However, a large number of the by-products from E. cava processing are discarded. In the present study, to utilize these by-products, we assessed the anti-inflammatory activity of the polyphenol-rich fraction (PRF) from E. cava processing by-product (EPB) in lipopolysaccharide (LPS)-induced RAW264.7 macrophage cells. Four compounds, namely eckol, eckstolonol, dieckol, and phlorofucofuroeckol-A, were isolated and identified from PRF. We found that PRF suppressed the production of nitric oxide (NO), inducible nitric oxide synthase, and cyclooxygenase-2 in the LPS-induced cells. Furthermore, the protective effect of PRF was investigated in vivo in LPS-stimulated inflammation zebrafish model. PRF had a protective effect against LPS-stimulated toxicity in zebrafish embryos. In addition, PRF inhibited LPS-stimulated reactive oxygen species and NO generation. According to the results, PRF isolated from EPB could be used as a beneficial anti-inflammatory agent, instead of discard.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.301-307
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• 2015

Phlorotannins and marine algal polyphenols, including dieckol, 6,6-bieckol, phloroglucinol, phlorofucofuroeckol-A, and eckol, were isolated from brown seaweeds. These compounds have beneficial bioactivities, and Ecklonia cava has become widely used for the extraction and isolation of phlorotannins. Eckol, in particular, has been to shown to have antioxidant, anti-inflammatory, anticoagulatory, and photoprotective properties. However, due to its low abundance in weaweed, the isolation and purification of eckol are difficult. Its limited availability renders the isolation and purification of eckol labor-intensive processes. Centrifugal partition chromatography (CPC) is an efficient technique for the isolation and purification of eckol. In this study, eckol was isolated from the ethyl acetate fraction of the 70% ethanol extract of E. cava using CPC with a two-phase solvent system of a n-hexane:EtOAc:methanol:water (2:8:3:7, v/v) solution. The purity and anti-inflammatory activity of the isolated eckol were verified by high-performance liquid chromatography and by assaying lipopolysaccharide-induced inflammatory responses in an immortalized murine BV2 microglial cell line, respectively. In conclusion, CPC is a useful technique for simple and efficient isolation of eckol from E. cava.