지충이(Sargassum thunbergii) 추출물의 항산화 효과
Antioxidant effect of sargassum thunbergii extracts
지충이 항산화효과 해조류 SARGASSUM THUNBERGII;
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This study is aimed at investigation of antioxidation effect and general composition of Sargassum thunbergii for its application to functional food. The antioxidation effect study was carried out by measuring reducing power with 2.2-diphenyl-1-picrylhydrazyl(DPPH), superoxide dismutase(SOD), nitrite-scavenging activity, thiobarbituric acid reactive sub-stances(TBARS), peroxid value(POV) and β-carotene-linoleate system. The general composition was analyzed by measuring contents of moisture, crude lipid, crude protein, mineral, amino acids and free sugars. 1. The Sargassum thunbergii was generally composed of 11.5% moisture, 0.7%crude lipid, 15.7% crude protein and 58.2% total sugar. The sugars was major component of Sargassum thunbergii. The mineral composition of Sarga-ssum thunbergii was following as (per 100g of dried sample weight) : Ca, 2,288㎎ ; Mg, 1,217㎎ ; Na, 811㎎ ; K, 759㎎ ; Fe, 483㎎. 2. Total content of composition amino acids was 5,635㎎% consisting of 1,017㎎% glutamic acid, 645㎎% aspartic acid, 470㎎% phenylalanine, 410㎎% alanine and 338㎎% leucine. Total content of free sugars was 99.7㎎% consisting of40.2㎎% galactose, 22.3㎎% mannose, 16.5㎎% maltose, 12.1 ㎎% sucrose and 8.6㎎% xylose. 3. Phenolic compounds contents of Sargassum thunbergii in extraction phases of chloroform and methanol were 22.5㎎ and 20.1㎎ per 100㎖ extraction solvent, respectively. Hydrogen donating activities were proportionaly increased with concentration of the extracts of Sargassum thunbergii obtained with extraction of solvents except hexane. The hydrogen-donating activities were 70% and 63% with extracts of methanol and water, respectively at concentration of 1000㎍/㎖, which were significantly higher than those activities obtained with other extracts. Nitrite-scavenging activity was measured at pH 2.5, 4.2 and 6.0 among which the highest activity was observed at pH 2.5. The nitrite-scavenging activities observed with extracts of methanol, chloroform, butanol and hexane at pH 2.5 were 90%, 88%, 85%, and 82%, respectively. It means that Sargassum thunbergii contains lots of substances showing high nitrite-scavenging activity. 4. SOD like ability of chloroform extract was stronger than other extracts. TBARS of chloroform extract was 1.5 MDA/L which was measured in addition of H2O2 oxygen species, 2.8 MDA/L in FeCl_(2) oxygen species, and 0.9 MDA/L in CuSO4 oxygen species. 5. All extracts of Sargassum thunbergii showed lower POV than a well-known natural antioxidant, ascorbic acid with which 18 meq/㎏ of POV was observed at 12 hours. Especially, chloroform extract among the extracts showed the strongest antioxidation activity of 4 meq/㎏ POV at 12 hours which was similar to POV of BHT, a well-known chemical antioxidant. 6. Antioxidant activities measured with β-carotene-linoleate system were 78% in methanol extract, 62% in chloroform extract, 51% in water extract and 43% in hexane extract. The antioxidation activity of methanol extract was higher than 72% BHA.