碩士 / 國立臺灣海洋大學 / 食品科學系 / 95 / This study investigated the antioxidative activity of seven edible seaweeds, Gelidium amansii, Gracilaria tenuistipitata, Ulva fasciata, Ulva intestinalis, Ulva clathrata, Monostroma nitidum, and Ulothrix flaccida, collected in Taiwan. The methanol extract, acid hydrolysate, and water extract of each individual seaweed were prepared to measure antioxidative activity, using the inhibition of hemoglobin-induced linoleic acid peroxidation, α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging, reducing power, and ferrous ion chelating as the indicators, and to calculate their IC50 values. Also, the total phenolic and total flavonoid contents were determined. And the active phenolic compounds were analyzed by seaweeds by using HPLC.
The IC50 values measured from methanol extract, acid hydrolysis, and water extract of seaweeds, were : 0.037~0.356 mg/mL, 0.007~0.216 mg/mL, 0.015~0.757 mg/mL for the inhibition of linolic acid peroxidation; 0.06~4.70 mg/mL, 0.32~0.70 mg/mL, 0.86~35.92 mg/mL for the effect on scavenging DPPH radical; 0.26~9.40 mg/mL, 0.64~4.07 mg/mL, 1.58~5.29 mg/mL for reducing power; and 0.37~5.77 mg/mL, 9.00~42.33 mg/mL, 0.53~12.59 mg/mL for the effect on chelating ferrous ion, respectively. Among the sample, Gelidium amansii (Rhodophyta), Ulva clathrata (Chlorophyta), and Ulva fasciata (Chlorophyta) exhibited higher antioxidant activities them others. High correlation (R2＞0.8) between antioxidant activity and total phenolic and total flavonoid contents were observed in methanol and water extracts.
Results of HPLC analysis showed that the total component of phenolics detected was the highest in methanol extract (30.13~1244.88 mg/g), followed by water extract (7.55~120.41 mg/g), and acid hydrolysate (0.86~131.43 mg/g). The most abundant amounts in methanol extracts of Rhodophyta and Chlorophyta samples were Gelidium amansii (1244.88 mg/g) and Monostroma nitidum (289.43 mg/g), in which the known major components were catechin and rutin in the former, and were catechol, catechin, epicatechin, and hesperidin in the latter.
| Identifer | oai:union.ndltd.org:TW/095NTOU5253080 |
| Date | January 2007 |
| Creators | Song-Bo Hou, 侯松伯 |
| Contributors | Tze-Kuei Chiou, Ph. D, 邱思魁 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 95 |
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