This study was conducted to investigate the antioxidant and radical scavenging activity of different extracts from Cook noni juice, including noni polysaccharide (noni-ppt), ethanol solute and ethyl acetate extract. Superoxide anion radicals and hydroxyl radicals were generated from autoxidation of pyrogallol (PR) and Fenton reaction (Fe2 +/H2O2). Furthermore 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) method was applied to evaluate the scavenging activity of the extracts. Malondialdehyde (MDA) ,the product of lipid peroxidation (LPO) was induced by adding Fe2+ into yolk homogenate. The ability of preventing LPO was measured by thibarbituric acid (TBA) method. All measurements were performed by spectrophotometric methods. The results suggested that the fraction of ethanol solute and ethyl acetate extract showed significant scavenging and antioxidant ability; L-ascorbic acid served as the standard. Noni-ppt had weaker activity on hydroxyl radical, DPPH radical, and LPO, and could accelerate the procedure of PR autoxidation. The abilities of the extracts may be related to their polarity.%本文对诺你果汁多糖、乙醇溶出物和乙酸乙酯萃取物体外对超氧阴离子(O2-·)、羟自由基(·OH)、DPPH和脂质过氧化(LPO)的抑制作用进行了研究.超氧阴离子(O2-·)由邻苯三酚自氧化产生;羟自由基(·OH)由Fenton反应产生;利用Fe2+诱发卵黄脂蛋白产生丙二醛(NDA),TBA法测定.所有测定均为分光光度法.结果表明,与已知抗氧化剂L-抗坏血酸相比,乙醇溶出物和乙酸乙酯萃取物均有明显的捕捉自由基和抗氧化能力,而多糖捕捉自由基和抗氧化能力很低,且对O2-·没有抑制作用,反而会增加其生成速度.
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