Dorema aitchisonii 之自由基清除及抗氧化活性   全文下載

Free Radical Scavenging and Antioxidant Activities of Dorema aitchisonii

本研究以體外試驗評估Dorema aitchisonii 莖葉之抗氧化特性，包括1,1-diphenyl-2-picryl hydrazyl自由基、一氧化氮及過氧化氫清除活性，鐵螯合能力，還原力及抑制血紅素催化亞麻油酸氧化能力等。抗溶血活性以過氧化氫誘導大鼠紅血球溶血試驗調查。以高效液相層析二極體陣列檢測器（HPLC/DAD）檢測沒食子酸，芸香?，槲皮素和香豆素含量。DPPH自由基清除活性之IC50為488 ± 18 μg/mL，D. aitchisonii萃取物之一氧化氮清除活性和鐵螯合能力均弱，分別為0.4 - 3.2 mg/mL和778 ± 22 μg/mL。 D. aitchisonii萃取物能有效抑制血紅素催化亞麻油酸氧化，但活性較維生素C低（p < 0.01）；以濃度依存方式清除過氧化氫，IC50為211 ± 11 μg/mL；呈現良好抗溶血活性，IC50為385 ± 15 μg/mL（維生素C對應值為235 ± 9 μg/mL）；總多酚含量41.2 ± 1.9 μg gallic acid equivalents/g；總類黃酮含量13.8 ± 0.8 mg quercetin equivalents/g，每mg之D. aitchisonii萃取物含7.27 μg芸香?、0.011 μg沒食子酸及微量之香豆素和槲皮素。儘管D. aitchisonii含多酚和類黃酮量，尤其是芸香?，其抗氧化活性極弱，然抗溶血活性佳。"

The aim of this study was to investigate the antioxidant properties of the aerial parts of Dorema aitchisonii by employing various in vitro assay systems including 1,1-diphenyl-2-picryl hydrazyl radical, nitric oxide and hydrogen peroxide-scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation. Antihemolytic activity was investigated against H2O2 induced hemolysis in rat erythrocytes. Gallic acid, rutin, quercetin and cumarin contents of the preparation were determined by HPLC with diode array detector (HPLC/DAD). The IC50 for DPPH radical-scavenging activity was 488 ± 18 µg/mL. The extract showed weak NO scavenging activity in the range of 0.4 and 3.2 mg/mL, as well as Fe2+ chelating ability (IC50 = 778 ± 22 µg/mL). The extract was effective in inhibiting hemoglobin-induced linoleic acid peroxidation, but its activity was less than Vitamin C (p < 0.01). The extract was capable of scavenging H2O2 in a concentration-dependent manner with an IC50 211 ± 11 µg/mL. The extract exhibited good antihemolytic activity with an IC50 385 ± 15 µg/mL (the corresponding value for Vitamin C being 235 ± 9 µg/mL). The total content of phenolic compounds was 41.2 ± 1.9 mg gallic acid equivalents/g and the total flavonoid content was 13.8 ± 0.8 mg quercetin equivalents/g. The extract contained 7.27 μg rutin and 0.011 μg gallic acid/mg extract, but cumarin and quercetin were present in trace amounts. In spite of presence of phenolic and flavonoid content, especially rutin, D. aitchisonii show weak antioxidant activity, but its antihemolytic activity was good.