Isoorientin-6″-O-glucoside, a water-soluble antioxidant isolated from Gentiana arisanensis

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• 作者：Ko ; Feng N. ; Chu ; Chen C. ; Lin ; Chun N. ; Chang ; Chia C. ; Teng ; Che-M.
• 关键词：Free radical ; DPPH ; Antioxidant ; LDL ; Isoorientin-6&Prime ; -O-glucoside ; (Gentiana arisanensis)
• 刊名：Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
• 出版年：1998
• 出版时间：January 15, 1998
• 年：1998
• 卷：1389
• 期：2
• 页码：81-90
• 全文大小：882 K

文摘

The antioxidant activities of isoorientin-6″-O-glucoside were studied using various models. Isoorientin-6″-O-glucoside was more potent than Trolox, probucol and butylated hydroxytoluene (BHT) in reducing the stable free radical 1,1-di-phenyl-2-picrylhydrazyl (DPPH). It also scavenged superoxide anion, peroxyl and hydroxyl radicals that were generated by xanthine/xanthine oxidase, 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) and Fe³⁺-ascorbate-EDTA-H₂O₂ system, respectively. The IC₅₀ value, stoichiometry factor and second-order rate constant were 9.0 ± 0.8 μM, 1.8 ± 0.1 and 2.6 × 10¹⁰ M⁻¹ s⁻¹ for superoxide generation, peroxyl and hydroxyl radicals. However, isoorientin-6″-O-glucoside did not inhibit xanthine oxidase activity or scavenge hydrogen peroxide (H₂O₂), carbon radical or 2,2′-azobis(2,4-dimethyl-valeronitrile) (AMVN)-derived peroxyl radical in hexane. Isoorientin-6″-O-glucoside inhibited Cu²⁺-induced oxidation of human low-density lipoprotein (LDL) as measured by fluorescence intensity, thiobarbituric acid-reactive substance formation and electrophoretic mobility. Since isoorientin-6″-O-glucoside did not possess pro-oxidant activity, it may be an effective water-soluble antioxidant that can prevent LDL against oxidation.