• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.166-175
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• 2008

In this study, we focused on natural water-soluble antioxidants from the Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis. They were prepared by enzymatic digestion using five carbohydrases (Viscozyme, Celluclast, AMG, Termamyl and Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme and Alcalase) and their potential antioxidant activity was assessed. Among the enzymatic digests, Neutrase digest from A. coffeaeformis exhibited the highest effect in DPPH radical scavenging. Flavourzyme (48.7%), Viscozyme (47.4%) and Celluclast (45.7%) digests from Navicula sp. exhibited higher $O^{{\cdot}-}_2$ radical scavenging activity. Viscozyme digest from A. coffeaeformis (45.9%) possessed the highest effects in hydroxyl radical scavenging. Termamyl (89.3%) and Protamex (88.8%) digests from A. coffeaeformis had strong metal chelating activity. Lipid peroxidation was significantly inhibited in Termamyl and Kojizyme digests from A. longipes, AMG and Termamyl digests from Navicula sp. and Kojizyme digest from A. coffeaeformisi. These data suggest that enzymatic digests of the Jeju benthic diatoms might be valuable sources of antioxidant which can be applied in food and pharmaceutical industry.

• ALGAE
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• v.24 no.1
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• pp.47-55
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• 2009

Recently, interest in plant-derived food additives has developed natural antioxidants, in order to alternate syn-thetic antioxidants with several disadvantages. In the present study, different organic fractions from solvent parti-tions of 80% methanol extract from Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis was assessed for their potential antioxidant effects. Among the solvent fractions tested, n-hexane (80.4%) and 80% methanol extract (76.6%) from A. longipes, chloroform (63.2%) from Navicula sp. and n-hexane (67.4%) from A. cof-feaeformis were effective in DPPH free radical scavenging. Fractions of chloroform (53.4%) and n-hexane (53.1%) from A. longipes exhibited higher activities on $H_2O_2$ scavengin. Fraction of n-Hexane from A. longipes exhibited the highest hydroxyl radical scavenging activity and NO. scavenging activity (56.5% and 75.6%, respectively). Aqueous residue from A. coffeaeformis (75.6%) showed the highest metal chelating effect. chloroform and ethyl acetate frac-tion of all the diatoms exhibited significant antioxidant activities in lipid peroxidation inhibitory activity. In particu-lar, both chloroform and the ethyl ecetate fraction from A. longipes and A. coffeaeformis exhibited lipid peroxidation inhibitory activity significantly higher than that of $\alpha$- tocopherol. These data suggest that the Jeju benthic diatoms tested are rich in hydrophilic and hydrophobic antioxidative compounds with different antioxidative properties that can be applied in food industry.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.174-186
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• 2007

Amphora coffeaeformis and Achnanthes longipes are commonly found as dominant benthic microalgae in Jeju coastal water throughout the year. In order to investigate pharmaceutical uses of these diatoms, each single species was isolated with micropipette under phase contrast microscope and subcultured with synthetic seawater media which was enriched with F/2 media, trace metal solution and $Na_2SiO_3$). Growth characteristics of these species were also determined with different combination of salinity, nutrients concentration and temperature. Thereafter, mass culture of each species was done based on the maximum growth condition. Biomass was collected after two weeks of mass culture and freeze dried for antioxidant study. The antioxidant properties of different fractions (n-hexane, chloroform and ethylacetate) obtained by solvent fractionation of 80% methanolic extract of two microalgae were investigated for free radical, reactive oxygen species scavenging (Super oxide, Hydrogen peroxide, Hydroxyl radical and Nitric oxide), metal chelating and lipid peroxidation inhibition activities. All fractions of A. longipes showed higher $DPPH^{\cdot}$ (free radical) scavenging activities (n-hexane: 89.0%, Chloroform: 76.0%, Ethylacetate: 66.0%, Methanol: 90.6% and aqueous residue: 63.0%). N-hexane fraction of A. longipes showed significantly higher activity (49.0%) on nitric-oxide. Ethylacetate fraction of A. longipes and aqueous residue of A. coffeaeformis exhibited 64.0% and 75.6% metal chelating activity which was higher than commercial antioxidants (${\alpha}$-tocopherol: 18.0% and BHT: 16.0%). The n-hexane fraction of A. coffeaeformis had 67.5% activity on $DPPH^{\cdot}$. Chloroform and n-hexane fractions of A. coffeaeformis exhibited 46.2% and 47.6% $H_2O_2$ scavenging effects which were closely similar to commercial antioxidants (${\alpha}$-tocopherol: 49.2% and BHT: 58.6%). Chloroform and ethylacetate fractions of A. longipes and fraction of n-hexane and chloroform of A. coffeaeformis showed better lipid peroxidation activities than ${\alpha}$-tocopherol. These data suggest that both organic and aqueous fractions have good antioxidative compounds with different antioxidant properties.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.225-227
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• 2001

출현한 식물플랑크톤은 82속 135종이었고 이중 Chrysophyta가 36속 63종(46.7%)로 가장 많이 출현하였다. 생태학적 주요종으로는 Aulacoseira granulata 등의 출현빈번종, Achnanthes longipes 등의 해수종, Actinastrum hantzschii var. fluviatile 등의 오수지표종 그리고 Ceratium furca등의 적조원인종이 출현하였다. 현존량은 1,000 ${cells/\ell}$ ～ 3,103,000 ${cells/\ell}$이었다. 우점종의 천이는 봄에 Pandorina morum, 여름에 Microcystis aeruginose, 가을과 겨울에 Oscillatoria tenuis, 겨울과 봄에 Phormidium tenue로의 천이양상을 보였다. 우점도지수는 0.34 ～ 0.94였고 종다양도지수는 0.5 ～ 2.57이었다. 오탁지수는 평균 2.4로 조사되어 $\beta$-중부수성 수역에 해당하였다. 유사도지수에 의한 집괴분석의 결과, 정점 1이 한그룹 그리고 정점 2, 3, 4가 한그룹, 정점 5가 한그룹으로 크게 3그룹으로 분석되어졌다.