| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 95 === Abstract
The purpose of this study was attempted to investigate the antioxidative activity of seven kinds of commonly used herbal tea materials. The methanol, hot water and hot water-methanol extracts were then prepared to measure antioxidative activities, total phenolic content and total flavonoid content. A HPLC method was also carried out to analyze active components.
Results showed that the scavenging effect on DPPH radical, reducing power, and inhibiton of linoleic acid peroxidation were higher in hot water extract than in methanolic extract. However, methanol extract had higher chelating effect on ferrous ion.
Among the materials, Artemisia capillaries, Kadsura japonica and Mesona procumbent were stronger in DPPH scavenging, Houttuynia cordata and Artemisia capillaries were stronger in chelating effect and reducing power, and Artemisia capillaries and Kadsura japonica were stronger in the inhibition of linoleic acid peroxidation. When antioxidative activities were expressed as IC50 values, the IC50 measured from methanol extracts were the lowest, followed by that from hot water extracts. In methanol extracts, the IC50 for scavenging DPPH (0.0062~0.0711 mg/mL), reducing power (0.0212~0.1370 mg/mL) and inhibition of linoleic acid peroxidation (0.0093~0.1062 mg/mL) were commonly smaller in Artemisia capillaries and Kadsura japonica than in others. But the IC50 for chelating ferrous ion (0.0015~0.0124 mg/mL) was the lowest in Houttuynia cordata.
The total phenolic and flavonoid contents in methanol (34.37~233.32 mg/g and 40.00~221.40 mg/g) and hot water (9.05~131.93 mg/g and 19.26~217.61 mg/g) extracts were much higher than that in hot water-methanol extract (total phenolic content: 1.40~17.94 mg/g; total flavonoid content: 0.95~19.27 mg/g). The total phenolic content was most abundant in Kadsura japonica and Artemisia capillaries, but that in Salvia plebeia was the lowest. The total flavonoid content was most rich in Artemisia capillaries, whereas Salvia plebeia and Houttuynia cordata contained the lowest. The samples were also analyzed for the presence of phenolic acids and flavonoids. A total of 11 components including gallic acid, catechin, catechin, caffeic acid, rutin, myricetin, morin, quercetin, luteolin, kaempferol and apigenin were detected and the total amount in samples was 1.12~44.32 mg/g. The major constituents in Mesona procumbent, Solanum violaceum, Artemisia capillaries, Ilex asprella and Salvia plebeia, however, were still unknown.
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