英语翻译The protective role of glutathione as an antioxidant and

英语翻译
The protective role of glutathione as an antioxidant and detoxifying agent has been demonstrated in various clinical studies.It is a ubiquitous compound that is synthesized rapidly in the liver,kidney,and other tissues,including the gastrointestinal tract.In animal cells,glutathione acts as a substrate for
glutathione peroxidase,which reduces lipid peroxides that are formed from polyunsaturated fatty acids (PUFA) in the diet,and as a substrate for glutathione-S transferase,which conjugates electrophilic compounds.Recent studies show that glutathione obtained from the diet is directly absorbed by the
gastrointestinal tract and thus dietary glutathione can readily increase the antioxidant status in humans (89).Dietary glutathione,in addition to levels supplied by the bile,may be used by the small intestine to decrease the absorption of peroxides.These results indicate that in the intact animal,luminal lutathione is available for use by the intestinal epithelium to metabolize peroxides and other reactive species and to prevent their transport to other tissue.Dietary glutathione occurs in highest amounts in fresh meats,in moderate amounts in some fruits and vegetables,whereas it is absent or found only in small amounts in grains and dairy products (90).Only fresh asparagus at 28.3 mg/100 g and fresh avocado at 27.7 mg/100

谷胱甘肽作为一种抗氧化剂及解毒剂的保护作用,已在各种临床研究中被证明出来.它是一种能快速合成、普遍存在肝,肾和其它组织之中(包括胃肠道)的化合物.在动物细胞中,谷胱甘肽作为谷胱甘肽过氧化物酶的酶底物,它能降低了在饮食中,源自多元不饱和脂肪酸（PUFA ）形成的脂质过氧化物,而且作为谷胱甘肽-S转移酶的酶底物,它还会和亲电化合物结合.最近的研究表明,从饮食中获得的谷胱甘肽会直接被
胃肠道吸收,因此膳食性谷胱甘肽可以很容易地增加人体中的抗氧化状态（ 89 ） .膳食性谷胱甘肽,除了由胆供给,可用于小肠降低过氧化物的吸收的程度外.这些研究结果都指出,在完整健康的动物体内,管腔谷胱甘肽可供肠上皮细胞使用,从而对氧化物和其它反应性物质进行代谢,并防止其传输到其它身体组织.膳食性谷胱甘肽在新鲜肉类中的含量最高,在一些水果和蔬菜中亦存在适量(膳食性谷胱甘肽),而不存在或仅少量发现於谷物和奶制品中（ 90 ）,只有新鲜的芦笋(28.3/100g)和新鲜鳄梨(27.7 mg/100)是例外