饲料中锰对日本沼虾抗氧化酶活性的影响

研究了日本沼虾(Macrobrachium nipponense)饲料中不同含量的Mn对虾体抗氧化酶活性的影响,以及在低氧胁迫下Mn对抗氧化酶的激活效果.结果表明,在投喂Mn的质量分数为150 ?g/g的饲料后,日本沼虾的超氧阴离子(O2·-)值降低,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性升高.Mn对虾体内SOD,CAT和GPX的激活作用表现出明显的剂量效应,饲料中Mn的缺乏或过量都使它们的活性受到影响.在低氧胁迫下,饲料中适量的Mn在一定程度上可提高虾体对低氧环境的耐受力.     

生姜提取物在油脂中抗氧化特性分析

利用各类溶剂来浸提生姜中有效抗氧化组分,并对提取物在猪油,花生油中的抗氧化能力进行了试验分析。研究结果表明,提取物对油脂抗氧化能力的强弱与溶剂的极性直接相关,生姜中的抗氧化组分应该是极性物质。论文还对利用溶剂浸提抗氧化组分的经济性开展了初步探讨。     

Causes of oxidative stress in Alzheimer disease

Oxidative stress is one of the earliest events of Alzheimer disease (AD), with implications as an important mediator in the onset, progression and pathogenesis of the disease. The generation of reactive oxygen species (ROS) and its consequent cellular damage/response contributes to much of the hallmark AD pathology seen in susceptible neurons. The sources of ROS-mediated damage appear to be multi-faceted in AD, with interactions between abnormal mitochondria, redox transition metals, and other factors. In this review, we provide an overview of these potential causes of oxidative stress in AD.     

Human endothelial senescence induced by IL-1α in vitro

Interleukin 1(IL-1) is an important proinflammatory cytokine that causes pleiotropic effects. Vascular endothelial cells stimulated by IL-1α can lead to the inflammatory response. Reactive oxygen species (ROS) are also generated at the site of inflammation and serve as an important factor against foreign invader. Here we report that long-term stimulation of human vein endothelial cells with IL-1α can accelerate their senescence associated with β-galactosidase activity. The flow cytometric analyses showed that most of the induced cells entered G0-G1 phase. DNA damage was more severe in senescent cells by comet assay. The induced cells by IL-1α had higher levels of ROS and malonyldialdehyde (MDA), lower activity of antioxidant enzymes and lower capacity of total antioxidant systems than control, which led to cell damage and cell degeneration, that is to say, which contributed to cellular senescence. Our results gave a direct proof to a new hypothesis-"the inflammation hypothesis of aging" on cellular level, and also provided a basis for the study on anti-aging and aging-related diseases.     

响应面法优化笃斯越橘混合菌发酵工艺

采用酵母菌、植物乳杆菌及醋酸菌对笃斯越橘进行混合发酵,通过测定基础指标(pH值、蛋白质、还原糖含量)、活性成分(总酚、黄酮、原花青素、花色苷含量)、抗氧化能力(·OH清除率、总抗氧化能力)确定菌种比例之后,以pH值、蛋白质含量、还原糖含量、总酚含量、·OH清除率及总抗氧化能力为考察指标,进行单因素实验以确定发酵时间、接种量、发酵温度及初始糖度的优化范围,在此基础上以总酚含量和·OH清除率为响应值进行Box-Benhken中心组合实验,优化发酵工艺条件。实验结果表明,在酵母菌、植物乳杆菌、醋酸菌菌种比例1∶2∶1,发酵时间62h,接种量6%,发酵温度38.5℃,初始糖度15.5°Bx的条件下,笃斯越橘发酵液的总酚质量浓度达(53.27±0.16)mg/(100mL),稀释10倍笃斯越橘发酵液的·OH清除率达(83.88±0.19)%,与优化前相比分别提高了56.91%和34.34%,其·OH清除率显著高于阳性对照组(p＜0.01),约为2mg/mL维生素C溶液的5倍。实验结果可为笃斯越橘的深加工提供实验参考依据。     

罗非鱼鱼鳞胶原多肽的优化制备及其生物活性研究

以罗非鱼鱼鳞为原料,采用碱性蛋白酶和胰蛋白酶复合水解,在单因素试验的基础上,采用响应面法优化酶解工艺,制备鱼鳞胶原多肽.测定胶原多肽的抗氧化活性、细菌低温保护活性、氨基酸组成及相对分子质量分布.结果显示,最适酶解条件为:底物质量浓度30.6 mg·m L-1、胰蛋白酶和碱性蛋白的加酶量分别为1.44和0.70 mg·m L-1、酶解温度50℃、pH值8.5、酶解时间6.35 h.酶解胶原多肽对DPPH自由基和羟基自由基的半数清除质量浓度(IC50)分别为2.89和3.54 mg·m L-1.经过细菌低温保护试验,当胶原多肽质量浓度为1 mg·m L-1时,嗜热链球菌的存活率达到75.6%.鱼鳞胶原肽相对分子质量分布显示,78%多肽片段的相对分子质量分布于180~2 000 u之间.氨基酸组成分析显示鱼鳞多肽富含甘氨酸、丙氨酸、脯氨酸、羟脯氨酸及天冬氨酸等,这些特定的氨基酸与胶原多肽的抗氧化活性、细菌低温保护活性相关.     

Antioxidant and prooxidant roles of copper in Tween 20-induced hemolysis of hamster and pig erythrocytes containing marginal vitamin E

The concentration-dependent effects of copper acting either as an antioxidant or as a prooxidant were examined in vitro using Tween 20-induced hemolysis. When cupric ion concentration was more than 10 M, free copper(II) acted as a prooxidant; both extensive hemolysis and production of unknown thiobarbituric acid-reactive substance occurred in hamster and pig erythrocytes irrespective of vitamin E status. However, when cupric ion concentration was 2–4 M in the incubation medium, copper showed a clear antioxidant activity, reducing both hemolysis and malondialdehyde production induced either by diluted peroxide-containing Tween 20 with ascorbic acid and sodium azide in vitamin E-deficient hamster erythrocytes, or by peroxide-containing Tween 20 in pig erythrocytes containing marginal amounts of vitamin E. Copper(II) is taken up by the erythrocytes, where copper(I)-complexes may contribute to the protection of cells with membrane vitamin E against oxidative radical attack.     

芫荽对生物大分子氧化损伤的保护作用及自由基清除能力

研究芫荽对生物大分子氧化损伤的保护作用及自由基清除能力,采用福林酚法检测芫荽的多酚含量,利用2,2′-偶氮二异丁基脒二盐酸盐(2,2′-azobis-2-methyl-propanimidamide,AAPH)作为体外氧化诱导剂,采用凝胶电泳检测芫荽对DNA和蛋白质的氧化损伤保护,用1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)法检测芫荽自由基清除率,用氧化自由基吸收能力(oxygen radical absorbance capacity,ORAC)分析检测芫荽的抗氧化能力值。结果表明,芫荽里的多酚类物质质量分数为4.054μg/mg；芫荽对DNA氧化损伤的最低保护质量浓度为4.0μg/mL,对牛血清蛋白的损伤保护质量浓度为125.0μg/mL；芫荽提取物对DPPH·的IC₅₀值为0.17μg/μL,芫荽提取物的ORAC值为485.3。综上所述,芫荽提取物具有较好的抗氧化活性。     

荭草素和异荭草素抗氧化活性及对肝癌细胞增殖的影响

采用荭草素和异荭草素标准品，通过测定两者对DPPH·、ABTS+·、H2O2、·OH自由基的清除率，脂质过氧化，Cu2+/H2O2诱导的牛血清蛋白-BSA-和DNA氧化损伤及BSA蛋白羰基化的抑制作用来评价二者的抗氧化活性，另外用MTT法评价了二者对人肝癌-HepG2-细胞生长的影响. 结果表明，荭草素和异荭草素均可清除自由基，抑制脂质过氧化、BSA和DNA氧化损伤和BSA羰基化，且一定浓度范围内异荭草素的抗氧化活性强于荭草素；另外荭草素和异荭草素可显著抑制HepG2细胞增殖，并呈浓度和时间依赖性，且异荭草素的抑制率高于荭草素，说明异荭草素是优于荭草素的有抗癌功效的天然抗氧化剂.     

高效液相色谱法测定食品中特丁基对苯二酚

用高效相色谱法测定食品中的抗氧化剂特丁基对苯二酚．样品经甲醇提取过滤后测定，检测波长为280nm，流动相为乙腈．1％乙酸（体积比为45：55），回收率为87．9％～95.1％，测定结果的相对标准偏差小于2％．