• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.144-151
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• 2012

In the course of this study aimed at the development of functional food ingredients from seaweeds, the in vitro antimicrobial activities of methanol extracts prepared from 35 different seaweeds (17 phaeophyta, 11 rhodophyta and 7 chlorophyta) were determined against food-borne diseases and pathogenic microorganisms including multi-drug resistant (MDR) Pseudomonas sp. and Candida sp. Based on disc-diffusion assays at 500 g/disc concentration of the methanol extracts, Ishige okamurai, I. foliacea, Sargassum confusum, and S. yamade exhibited strong antibacterial activities in a broad-spectrum, except against Pseudomonas aeruginosa. In addition to the latter four seaweeds, Ecklonia stolonifera, E. cava and Eisenia bicyclis also demonstrated antifungal activity against C. albicans. Among these 8 selected seaweeds, I. okamurai, I. foliacea, and S. yamade exhibited strong hemolytic activity (55-93%) at 500 g/ml against human RBC. Organic solvent sequential fractions using hexane, ethylacetate and butanol, and water residues were prepared from the 8 selected seaweeds and their anti-Candida sp. activities were further determined. The ethylacetate and butanol fraction of I. okamurai, and the hexane fraction of I. foliacea demonstrated antifungal activity against MDR-pathogenic Candida sp. Although the solvent fractions had no activity against MDR-Pseudomonas sp., our results suggest that seaweeds, especially Ishige okamurai, I. foliacea, S. confusum, and S. yamade could be developed as broad-spectrum antimicrobial ingredients.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.197-198
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• 2002

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1485-1490
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• 2008

The effects of $\gamma$-irradiation on antioxidant and physicochemical properties of powder and 70% fermented ethanol extracts of Ishige okamurai (I. okamurai) were investigated. In case of powder, although yields were increased, there were no significant changes in total phenolic compounds (TPC) and 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect by $\gamma$-irradiation at 3, 7, and 20 kGy. In case of 70% fermented ethanol extracts, the results of TPC and DPPH radical scavenging effects showed no significant changes. However, antioxidant index increased in the 20 kGy irradiated I. okamurai extracts and decreased in 3 kGy irradiated ones. The optical density value of UV spectrum at 427 nm significantly decreased depending on increasing irradiation dosage. In conclusion, irradiated extracts of I. okamurai can be applied to the food industry due to irradiation stability on antioxidant properties. Also, irradiated extracts can be more useful for food processing as a result of a decrease of extracts color by irradiation.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.50-56
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• 2009

This study was carried out to determine the optimum extraction conditions for Ishige okamurai by comparing the yields, total phenolic compound content (TPC), and antioxidant properties of its 95%, 70%, 50% fermented ethyl alcohol and water extracts. Additionally, the effects of heat and pH treatments on the antioxidant properties of the extracts were evaluated by their TPC and 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging capabilities. The yields of the extracts were greatest in the order of water > 50% > 70% > 95% fermented ethyl alcohol, and the TPC of the 70% (26.18%) and 50% fermented ethyl alcohol (27.56%) extracts were higher than those of the others. However, in terms of DPPH radical scavenging and ferrous-reducing power, the 70% fermented ethyl alcohol extract of Ishige okamurai showed the highest antioxidant effects. Additionally, in the results for the heat and pH treatments, the antioxidant properties of the 70% fermented ethyl alcohol extract were not influenced by the treatment conditions except at pH 10.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.201-207
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• 2008

In this study, we investigated the antimicrobial and antifungal activity from the wild seaweeds of Jeju island. The active ingredients of the seaweeds were prepared by 80% methanol extraction. Antimicrobial and antifungal activity of seaweed extracts was examined. We found that 6 plant extracts among 45 plants, namely, Codium contractum, Undaria pinnatifida, Ishige sinicola, Ishige okamurai, Ishige okamuriai, Ecklonia cava, Hizikia fusiformis, Ulva fasciata, Ulva pertusa, Sargassum siliquastrum, Ecklonia kurome, Gracilaria textorii, significantly inhibited growth of harmful microorganisms. Additionally, according to DPPH assay. 2 plant extracts were found to have antioxidant activities. Taken together, these results suggest the possibility that 11 plant extracts can be utilized as an antimicrobial agent.

• Journal of Plant Biology
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• v.19 no.4
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• pp.111-118
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• 1976

The marine algal vegetation of spring season in the intertidal belt of Jeju Island, Korea, was carried out by the quadrat method at 4 transects; Moseulpo, Kangjeong, Whabug, and Hado in 1976. The transects were divided into 5 stations by exposed frequencies of the substratum from water, such as more than 50%, 46-49%, 28-45%, 7-27%, and less than 6%. As a result, the algal vegetations were separated into three groups, high, middle and low algal communities. The representative dominant species of each group are aas follows. High algal community: Porphyra suborbiculata, Bangia fusco-purpurea, Gloiopeltis furcata. Middle algal community: Ishige okamurai, Hizikia fusiforme, Corallina pilulifera, Sargassum thunbergii. Low algal community: Sargassum ringgoldianum, Sarg. confusum. The coverage of these groups is 43.5, 57.6%, and 77.3%, respectively.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.506-512
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• 2009

The antimicrobial activity of water and ethanol extracts from 30 species of algae was measured using the agar diffusion method and minimum inhibitory concentration (MIC) test. In agar diffusion method, the 95% ethanol extracts from 12 of the algae showed growth inhibition against the tested microorganisms. In particular, Ishige okamurai, Ecklonia stolonifera, Sargassum siliquastrum, Sargassum thunbergii, Colpomenia bullosa, and Ecklonia cava had strong antibacterial activities against Gram-positive bacteria at 4 mg/mL. In the results of the MIC test, S. siliquastrum showed the most antimicrobial activity, where its MIC values ranged from 0.005 to 0.0075% against Listeria monocytogenes, Clostridium perfringens, and Basillus subtilis. In the thermal stability test, for the ethanol extracts of I. okamurai, E. cava, S. siliquastrum, S. thunbergii, and C. bullosa, the extracts proved to maintain high antimicrobial activities when they were treated at $121^{\circ}C$ for 15 min. In the pH stability test, the antimicrobial activity of the S. siliquastrum ethanol extract was stable from pH 2 to 10, whereas the activity of the other species ethanol extracts were weakened under pH 10 against several microbes.

• Journal of Marine Bioscience and Biotechnology
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• v.5 no.4
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• pp.33-39
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• 2011

As a rapid and quick bioactive compound evaluation technique, we utilized an automatic system of high throughput screening (HTS) to investigate ${\alpha}$-glucosidase inhibitory efficacy of seaweeds, collected from Jeju Island in Korea. In this study, different extracts with methanol at $20^{\circ}C$ and $70^{\circ}C$ from 23 species of brown seaweeds and 22 species of red seaweeds and 9 species of green seaweeds were subjected to HTS. Of the brown seaweeds tested, Myelophycus simplex (20B3), Ishige sinicola (20B5, 70B5), Colpomenia sinuosa, (20B14, 70B14), Hizikia fusiforme (20B21), Ishige okamurai (70B22) and Ecklonia cava (70B23) showed significantly high ${\alpha}$-glucosidase inhibitory activity with 96.52%, 98.34%, 98.37%, 80.49%, 96.16%, 76.32%, 98.32% and 98.12%. Schizymenia dubyi (20R15), Gelidium amansii (20R16) and Polysiphonia japonica (70R22) amomng the red seaweeds showed remarkable ${\alpha}$-glucosidase inhibitory activity more than 95%. On the other hand, the green seaweeds showed poor ${\alpha}$-glucosidase inhibitory activities (less the10%) at 1 mg/ml.

• Journal of Life Science
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• v.21 no.4
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• pp.576-583
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• 2011

In the course of study for the development of functional food ingredients from seaweeds having useful biological activities, the in-vitro antioxidant and nitrite scavenging activities of the methanol extracts prepared from 35 different seaweeds (17 phaeophyta, 11 rhodophyta and 7 chlorophyta) were determined. At $500\;{\mu}g/ml$ concentration of the methanol extracts, Ecklonia cava, Ecklonia stolonifera, Eisenia bicyclis (Kjellman) Setchell, Ishige foliacea, I. okamurai, Sargassum confusum, S. fulvellum, S. yamade and Zostera marina showed 60% more DPPH and ABTS scavenging activity. The exceptions were found in I. okamurai and Z. marina, which showed 45% and 53% ABTS scavenging activity, respectively. The correlation coefficient between DPPH and ABTS scavenging activities was 0.855, suggesting that the 9 different seaweeds extracts could scavenge anion and cation radicals concurrently. In reducing power, only E.cava, E.stolonifera and E.bicyclis showed above 0.88 ($Abs_{700}$). In a while, in nitrite scavenging activity at $100\;{\mu}g/ml$ concentration of the methanol extracts, 19 different seaweeds extracts including I. foliacea, I. okamurai, S. confusum, S. fulvellum, and S. yamade showed 60% more activity. Calculation of $IC_{50}s$ of DPPH, ABTS and nitrite scavenging activities of 9 different seaweeds extracts further showed that I. foliacea and S. yamade, besides E.cava, E.stolonifera and E.bicyclis, have strong antioxidant and nitrite scavenging activity. These results suggest that the selected 9 different seaweeds could be developed as functional food ingredients and I. foliacea and S. yamade have potential as novel natural sources of antioxidant and nitrite scavenger.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.265-273
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• 1986

The marine algal communities of Yonhwa-do at the southern coast of Korea were investigated in aspects to quantitative analysis of their structure and dynamics. As a result, 114 species, including 2 blue-green, 69 red, 25 brown and 18 green algae, were identified. The R/P value(2.8) is higher than that of other regions of the southern coast of Korea. Sheet and filamentous groups of the functional groups of algae showed higher composition rate in spring and summer than in autumn and winter, but coarsely branched and thick leathery groups showed an opposite tendency. Cluster analysis based on species presence suggested the existence of 5 distinct groups in spring, but 3 groups in the other seasons. The species exhibiting important value above 20 were as follows: Porphyra suborbiculata, Corallina pilulifera, Hizikia fusiforme, Sargassum thunbergii, Undaria pinnatifida, Ishige okamurai, Chondria crassicaulis, and crustose coralline algae. The coverage of algal communities composed only of crustose coralline algal complex was higher than that of other algal complex, but occurrence frequency of these two communities was indifferent. It is suggested that the occurrence in high quantity of crustose coralline algae from this area is related to grazing by herbivorous animals.