• Journal of Aquaculture
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• v.20 no.1
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• pp.7-13
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• 2007

The seed production of Ecklonia stolonifera Okamura was studied under laboratory conditions through the embryonic sporophyte stage and the field cultivation was conducted in eastern coast of Korea. The germination of zoospores occurred within 3 days and the growth of gametophytes was most rapid at $25^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}s^{-1}$. Sporophyte growth was highest at $20^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}s^{-1}$ and lowest at $25^{\circ}C$ and $80\;{\mu}mol{\cdot}m^{-2}s^{-1}$. In the nursery culture of E. stolonifera lasting for 2 weeks in January, the initial blade length of E. stolonifera (about $500\;{\mu}m$) grew to $526.3{\pm}176.0\;{\mu}m$ at water temperature of $12.05^{\circ}C$. The blade length and width reached their maxima in July, after which the ends of blade and stem began to degrade with the increase in water temperature. The degraded end of the blade started to regenerate in October, when water temperature began to decline. This species can be considered a potential candidate for aquaculture, increasing in the availability of raw material and aiding in recovery of seaweed bed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.909-915
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• 1997

The nitrite scavenging effect of methanol extracts of marine algae were evaluated to discover new natural nitrite scavengers. Among the tested seaweeds, Ecklonia stolonifera, an edible brown algae, showed the strongest scavenging effect. The MeOH extract was then sequentially partitioned into $CH_2Cl_2,\;CH_2Cl_2$ insoluble interface, EtOAc, n-BuOH, and $H_2O$ layers. The EtOAc and n-BuOH fraction demonstrated high levels of nitrite-scavenging activity while the $CH_2Cl_2,\;CH_2Cl_2$ insoluble interface, and $H_2O$ fractions were inactive. A column chromatography of the EtOAc fraction through silica gel and Sephadex LH-20 yielded phloroglucinol and a new compound tentatively named phlorotannin A. The nitrite scavenging activity of phloroglucinol $(IC_{50}=3.9{\mu}g/ml)$ was more potent than that of L-ascorbic acid $(IC_{50}=65.0{\mu}g/ml)$. However, phlorotannin A $(IC_{50}=193.2{\mu}g/ml)$ showed only low levels of activity. From the above results, it is possible to suggest that both the MeOH extract and their fractions and isolated phloroglucinol and phlorotannin A obtained from E. stolonifera may be applicable as scavengers of nitrite, which is a precursor for the formation of carcinogenic N-nitroso compounds.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.581-586
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• 1998

The present study was conducted to prepare seaweed extracts suppressing mutagenic activity of 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine ( PhIP ) ana 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx) derived from cooked meat produce. The tumor initiation activity of PhIP and MeIQx was assayed with Ames method using Salmonella typhimurium TA98 in the presence of S-9 mixtures before and after addition of methanol-solubles of seaweed, such as, Phaeophyta; Undaria pinnatifida, Ecklonia stolonifera Ecklonia cava, Laminaia japonica Sargassum fulvellum, Sargassum hornezi, Sargassum miyabei, Sargassum thunbergii, Agarum cribrosum and Hizikia fusifomis, Rhodophpei Porphyra yezoensis, Grateloupia eiliptiut Lomentraria catenata, Ploemium telfairiae and Glarilaria verrucosa, Chlorophyta; Codium fragile, Enteromorpha compresa and Ulva pertusa. Among seaweed tested, Phaeophyta was shown the higher desmutagenic activity than Rhodophyta and Chlorophyta. E. stolonifera, E. cava and S. miyabei, among Phaeophyta exerted the stronger desmutagenic activity (above $90\%$/2 mg). The ethyl acetate, diethyl ether and chlomform extracts except water extracts from E. stolonifera exhibited a high desmutagenic activity. The ethyl acetate extract of E. stolonifera which showed highest activity was fractionated with Sephadex LH20 column chromatography to give active fraction A-7, which showed desmutagenicity of $90\%$/mg against PhIP and $80\%$/mg against MeIQx. The active fraction had the absorbance at 207.7 and 232nm.

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.195-199
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• 2000

Tyrosinase inhibitory activities of 14 kinds of seaweed, Ecklonia stolonifera, Ecklonia cava, Undaria pinnatiflda, Laminaria japonica, Sargassum fulvellum, Sargassum miyabei, Sargassum thunbergii, Porphyra yezoensis, Gracilaria verrucosa, Carpopeltis affinis, Pachymeniopsis elliptica, Gelidium amansii, Codium fragile and Ulva pertusa were determined using commercially available mushroom tyrosinase in an in vitro assay system. The $1\%$ (w/v) methanol extract from E. stolonifera showed the highest tyrosinase inhibitory activity of $79.0\%$, electron donating activity of $79.0\%$ and total phenol content of 3.75 mg/100g. Ethyl acetate-methanol-water (7 : 2 : 0.2, v/v) fraction $(0.5\%,\;w/v)$ isolated from the methanol extract showed tyrosinase inhibitory activity of $75.9 \%$, electron donating activity of $88.1 \%$ and total phenol content of 4.38 mg/100g. Tyrosinase inhibitory activity was closely associated with total phenol content (R = 0.99) and electron donating activity (R=0.99). Maximum absorption wavelength of the fraction was 218nm and that of phenolic compounds showed about a range from 210 to 220nm. The inhibition mode of the fraction was noncompetitive inhibition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.439-446
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• 2015

Inflammation is a protective response to infection or injury. However, prolonged inflammation can contribute to the pathogenesis of many diseases, such as cancer, diabetes, arthritis, atherosclerosis, and Alzheimer's disease. Recent studies have shown that activated macrophages, inflammatory effector cells, can react to tissue insults in a polarized manner, in which their phenotypes are polarized into two major subtypes, categorized as M1 or M2. Classical M1 activation involves the production of pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-${\alpha}$, and free radicals, while M2 or alternative activation is an anti-inflammatory phenotype involved in homeostatic processes, such as wound healing, debris scavenging, and the dampening of inflammation via the production of very low levels of pro-inflammatory cytokines and high levels of anti-inflammatory mediators, including IL-10. As part of our ongoing effort to isolate anti-inflammatory compounds from seaweeds, we investigated the effects of phlorotannins isolated from the brown alga Ecklonia stolonifera on macrophage polarization. Mouse peritoneal macrophages were treated with various concentrations of the extracts, and real-time RT-PCR analyses were performed to examine the expression of polarization markers: IL-$1{\beta}$, IL-6, and TNF-${\alpha}$ for M1 and arginase-1, peroxisome proliferator-activated receptor (PPAR)-${\gamma}$, found inflammatory zone-1 (Fizz-1), chitinase 3-like 3 (Ym1), and$Kr{\ddot{u}}ppel$-like factor 4 (Klf-4) for M2. The pretreatment of cells with eckol, dieckol, and phlorofucofuroeckol-A (PFF-A), isolated from the ethyl acetate fraction of E. stolonifera ethanolic extract, potentiated the anti-inflammatory M2 phenotype of the macrophages. These results indicate that phlorotannins derived from E. stolonifera can be used to enrich macrophages with markers of the M2 anti-inflammatory state.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.370-378
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• 2005

The characteristics of heavy metal biosorption on the seaweeds were investigated to develop a biological treatment technology for wastewater polluted with heavy metals. The heavy metal biosorption on seaweeds ranked in the tallowing order: U. pinnatifida$\geq$E. stolonifera$\geq$Laminaria sp.>G. amansii. The Pb was biosorbed in the range of $93{\sim}99%$, and the Cu and Cd were biosorbed in the range of $70{\sim}80%$ at the concentration of the heavy metal of $100mg/{\ell}$ respectively. The seaweed which was pretreated with $CaCl_2$ solution improved the biosorption of the heavy metals. The temperature and pH didn't affect the biosorption of heavy metals. The Langmuir isotherm reasonably fit the data of heavy metal biosorption compared to the Freundlich isotherm. The affinity of metals on the biosorption ranked in the following order: Pb>Zn>Cu>Cd. The biosorption efficiency of the heavy metals on the U. pinnatifida decreased in the multi-component rather than the single component. The heavy metals adsorbed on the U. pinnatifida were recovered using 0.3%-NTA. U. pinnatifida among the seaweed used in this work showed the best performance for the biosorption of the heavy metals.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.218-223
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• 2018

The liver is an essential organ for the detoxification of exogenous xenobiotics, drugs and toxic substances. The incidence rate of non-alcoholic liver injury increases due to dietary habit change and drug use increase. Our previous study demonstrated that Ecklonia stolonifera (ES) formulation has hepatoprotective effect against alcohol-induced liver injury in rat and tacrine-induced hepatotoxicity in HepG2 cells. This present study was designated to elucidate hepatoprotective effects of ES formulation against carbon tetrachloride ($CCl_4$)-induced liver injury in Sprague Dawley rat. Sixty rats were randomly divided into six groups. The rats were treated orally with ES formulation and silymarin (served as positive control, only 100 mg/kg/day) at a dose of 50, 100, or 200 mg/kg/day for 21 days. Seven days after treatment, liver injury was induced by intraperitoneal injection of $CCl_4$ (1.5 ml/kg, twice a week for 14 days). The administration of $CCl_4$ exhibited significant elevation of hepatic enzymes (like AST and ALT), and decrease of antioxidant related enzymes (superoxide dismutase, glutathione peroxidase and catalase) and glutathione. Then, it leaded to DNA damages (8-oxo-2'-deoxyguanosine) and lipid peroxidation (malondialdehyde). Administration of ES formulation inhibited imbalance of above factors compared to $CCl_4$ induced rat in a dose dependent manner. Real time PCR analysis indicates that CYP2E1 was upregulated in $CCl_4$ induced rat. However, increased gene expression was compromised by ES formulation treatment. These findings suggests that ES formulation could protect hepatotoxicity caused by $CCl_4$ via two pathways: elevation of antioxidant enzymes and normalization of CYP2E1 enzyme.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.587-593
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• 1998

To elucidate anti-tumor promoter from seaweed, the anti-tumor promoting activity of Ecklonia stolonifera, Undaria pinnatifida and Laminaria japonica extracts were determined by Epstein-Barr virus (EBV)-early antigen (EA) induction caused by a tumor promoter, teleocidin B-4. The methanol extracts of seaweed were subsequently fractionated with diethyl ether, distilled water, chloroform and ethyl acetate. Among the solvent fractions tested, chloroform and ethyl acetate fraction of E. stolonifera showed a high anti-tumor promoting activity at the levels of 88.0 and $85.9\%$ by the addition of 20 ${\mu}g/m{\ell}$, respectively. To characterize anti-tumor promoters from solvent fractions of E. stolonifera, the effects of phenols, chlorophyll derivatives and carotenoids on the anti-tumor promoting activity were investigated. Phenols, such as bromophenol and phloroglucinol showed anti-tumor promoting activity of $57\~66\%$ at 20 ${\mu}g/m{\ell}$. Pigments, such as chlorophylls and carotenoids exerted high anti-tumor promoting activities. Chlorophyll a and pheophorbide a exhibited the activity of $77.4\%$ and $66.6\%$ at 5${\mu}M/m{\ell}$, respectively. The active compounds of carotenoids were tentatively identified as lutein and $\alpha-cryptoxanthin$ from the profiles of visible spectra and R_f value of their authentic compounds, and showed anti-tumor promoting activities of $76.9\%$ and $84.4\%$ at dose of 20 ${\mu}g/m{\ell}$, respectively.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1226-1232
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• 2004

Extracts from seventeen seaweeds were determined for tyrosinase inhibitory activity using mushroom tyrosinase with L-tyrosine as a substrate. Only one of them, Ecklonia stolonifera OKAMURA (Laminariaceae) belonging to brown algae, showed high tyrosinase inhibitory activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction from the methanolic extract of E. stolonifera, led us to the isolation of phloroglucinol derivatives [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 1~5 were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with $IC_{50}$ values of 92.8, 126, 33.2, 177, and 2.16 ${\mu}g$ /mL, respectively. It was compared with those of kojic acid and arbutin, well-known tyrosinase inhibitors, with $IC_{50}$ values of 6.32 and 112 ${\mu}g$ / mL, respectively. The inhibitory kinetics analyzed from Lineweaver-Burk plots, showed compounds 1 and 2 to be competitive inhibitors with $K_i$ of $2.3{\times}10^{-4}\;and\;3.1{times}10^{-4}$ M, and compounds 3~5 to be noncompetitive inhibitors with $K_i$ of $1.9{\times}10^{-5},\;1.4{\times}10^{-3}\;and\;1.5{\times}10^{-5}$ M, respectively. This work showed that phloroglucinol derivatives, natural compounds found in brown algae, could be involved in the control of pigmentation in plants and other organisms through inhibition of tyrosinase activity using L-tyrosine as a substrate.