高手们帮帮忙!帮我翻译段英文!急用!小弟先谢谢了!

高手们帮帮忙!帮我翻译段英文!急用!小弟先谢谢了!
The human body, constantly exposed to free radicals, evolved a complex defence system, including compounds that prevent the formation of new radicals by removing peroxides, by dismutating superoxides, by chelating metal ions and compounds that inhibit the propagation of peroxidation (the so-called chain-breaking antioxidants) [4]. Dietary modulation of oxidative stress, however, involves mainly the chain-breaking antioxidants. Essential dietary antioxidants, including vitamin A, C and E are involved in oxidative stress control, as are carotene and carotenoids [1,2]. However, numerous non-essential dietary compounds such as phenolics are also considered antiatherosclerotic and anticarcinogenic and presumably play a role in controlling oxidative reactions in vivo [5]. While these antioxidants seem to be important physiologically, very little is known about the absorption, incorporation, metabolic fate and antioxidant action in humans.
The concentration of each of these antioxidants and their relative antioxidant activity (that is the amount of free radicals trapped per mole), and their possible synergism contributes to the total antioxidant capacity. This parameter, therefore, represents a more integrated measure than the simple evaluation of the content of individual antioxidants, and includes all unmeasured or unmeasurable compounds. The methods available for this purpose take advantage of a constant peroxyl radical flow produced by thermal decomposition of an azocompound [8]. This flow leads to the oxidation of a target molecule, whose decay is a measure of the lipid peroxidation reaction and, indirectly, of the ability of plasma, body fluids or simple chemical solutions to break the reaction. Figure 1 resumes the method we used to assess the antioxidant capacity of plasma or antioxidant compounds [3]. A constant flow of peroxyl radicals is obtained by adding 4 mM AAPH to a reaction mixture consisting in 150 nM R-Phycoerythrin (R-PE) when plasma (or antioxidants) is added, a lag phase is produced. The plasma antioxidant capacity can be quantified, by standardizing the lag-phase induced by plasma with that induced by a known amount of an antioxidant compound (Trolox).
The antioxidant potential produced by ascorbate, urate, tocopherol, and thiol groups accounted only for 67% of the total antioxidant capacity. The remaining 23% may be explained by other compounds present in plasma (carotenoids, retinol, bilirubin, creatinine, polyphenols) which could play an important antioxidant role. To evaluate whether dietary phenolics significantly contribute to systemic antioxidant defences we studied plasma antioxidant capacity in human beings before and after consumption of polyphenol-rich beverages (tea and wine).

人体,经常被暴露在自由基,演变一个复杂防御系统,包括通过去除过氧化物防止新的基础形成,通过dismutating过氧化物,通过结为螯合物金属离子和化合物禁止过氧化的化合物(所谓的链子打破的抗氧剂) [4的]传播.氧化重音的饮食模块化,然而,介入主要链子打破的抗氧剂.根本饮食抗氧剂,包括维生素A,C和E在氧化压力控制介入,象胡萝卜素和类胡萝卜素[1,2].然而,许多非本质饮食化合物例如酚醛树脂在控制氧化反应也被认为antiatherosclerotic和anticarcinogenic和据推测扮演一个角色体内[5].当这些抗氧剂生理地时似乎是重要的,很少知道关于在人的吸收、并网、新陈代谢的命运和抗氧化行动.的The集中是每摩尔被困住的相当数量自由基)这些抗氧剂和他们的每一相对抗氧化活动(和他们可能的协同作用造成总抗氧化容量.这个参量,因此,比各自的抗氧剂内容的简单的评估代表一项更加联合的措施,并且包括所有不可测或不可测量的化合物.可利用的方法为此利用azocompound [8的]热分解导致的恒定的peroxyl根本流程.这流程,间接地,导致目标分子的氧化作用,朽烂是油脂过氧化反应措施,并且等离子、体液或者简单的化工解答的能力打破反应.图1恢复我们曾经估计抗氧化容量等离子或抗氧剂化合物的方法[3].peroxyl基础恒流通过增加4 mM获得AAPH到包括在150毫微米R藻红素(R-PE)的反应混合物,当等离子(或抗氧剂)时增加,停滞阶段被生产.等离子抗氧化容量可以通过规范化与已知的相当数量导致的那的等离子导致的停滞阶段定量,一种抗氧化化合物(Trolox).
The抗氧化潜力由抗坏血酸,urate,维生素E生产了,并且硫烃小组仅占67%总抗氧化容量.保持的23%也许用其他化合物解释当前在可能扮演一个重要抗氧化角色的等离子(类胡萝卜素、松香油、胆红素、肌氨酸酐,多酚).要评估饮食酚醛树脂是否极大造成系统抗氧化防御我们学习在人的等离子抗氧化容量在富有多酚的饮料的消耗量前后(茶和酒).