Noda Y, Anzai K, Mori A, Kohno M, Shinmei M, Packer L
Department of Molecular and Cell Biology, University of California at Berkeley 94720-3200, USA.
Biochem Mol Biol Int. 1997 Jun;42(1):35-44. doi: 10.1080/15216549700202411.
Free radical scavenging activities of water-soluble extracts from some natural sources, health foods, and antioxidant substances were measured using the JES-FR30 JEOL spectrometer. The objective was to develop a standardized method whereby comparison could be made between the radical scavenging activities of complex mixtures. Scavenging of hydroxyl radical was determined using DMPO. Activity was calibrated using a standard material, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H -1- benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1), an analog of vitamin C and vitamin E which is water soluble and stable at room temperature. The order of greatest hydroxyl radical scavenging activity was green tea extract, pine bark extract (Pycnogenol), Ginkgo Biloba extract (EGb 761), a flavonoid blend of several fruit and vegetable extracts (GNLD), and Bio-Normalizer (Sun-O Corp). Activity was determined after treatment of samples with ascorbic acid oxidase. This treatment revealed the presence of ascorbate in some natural extracts and commercial preparations. The pine bark extract was the most heat resistant and had ascorbate-like activity in the preparations. Scavenging of superoxide anion was determined using the spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and analyzed by comparison with a standard curve made with superoxide dismutase. Comparison of the water solubilized components of natural source antioxidants showed that filtrates fractionated using centrifuge type Millipore filter tubes (M.W. < 100,000; M.W. < 10,000) also had almost the same SOD-like activity. Samples were also treated with ascorbate oxidase or by heating (100 degrees C for 10 min). The order of activity, from greatest to least, was Ginkgo biloba extract EGb 761, pycnogenol, beta-catechin, tea and BioNormalizer.
使用JES-FR30 JEOL光谱仪测量了一些天然来源、健康食品和抗氧化物质的水溶性提取物的自由基清除活性。目的是开发一种标准化方法，以便能够比较复杂混合物的自由基清除活性。使用DMPO测定羟基自由基的清除情况。活性通过标准物质L-抗坏血酸2-[3,4-二氢-2,5,7,8-四甲基-2-(4,8,12-三甲基十三烷基)-2H-1-苯并吡喃-6-基-氢磷酸酯]钾盐（EPC-K1）进行校准，EPC-K1是维生素C和维生素E的类似物，水溶性且在室温下稳定。羟基自由基清除活性最高的顺序为绿茶提取物、松树皮提取物（碧萝芷）、银杏叶提取物（EGb 761）、几种水果和蔬菜提取物的类黄酮混合物（GNLD）以及Bio-Normalizer（Sun-O公司）。在用抗坏血酸氧化酶处理样品后测定活性。该处理揭示了一些天然提取物和商业制剂中存在抗坏血酸盐。松树皮提取物耐热性最强，并且在制剂中具有类似抗坏血酸盐的活性。使用自旋捕获剂5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）测定超氧阴离子的清除情况，并通过与用超氧化物歧化酶绘制的标准曲线进行比较来分析。对天然来源抗氧化剂的水溶性成分进行比较表明，使用离心式密理博滤管（分子量<100,000；分子量<10,000）分级的滤液也具有几乎相同的类超氧化物歧化酶活性。样品还用抗坏血酸氧化酶处理或加热（100℃10分钟）。活性顺序从高到低为银杏叶提取物EGb 761、碧萝芷、β-儿茶素、茶和BioNormalizer。
