Aqueous extracts of selenium-fertilized broccoli increase selenoprotein activity and inhibit DNA single-strand breaks, but decrease the activity of quinone reductase in Hepa 1c1c7 cells.
Aqueous extracts of selenium-fertilized broccoli increase selenoprotein activity and inhibit DNA single-strand breaks, but decrease the activity of quinone reductase in Hepa 1c1c7 cells.
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DOI：
10.1016/j.fct.2005.10.002
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发表时间：
2006-05
期刊：
影响因子：
--
通讯作者：
Anna-Sigrid Keck;J. Finley
中科院分区：
文献类型：
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作者：
Anna-Sigrid Keck;J. Finley
根据生长条件，西兰花可能富含异硫氰酸酯萝卜硫素和/或矿物质硒（Se）;这两种化合物可能在减少细胞内氧化应激和预防慢性疾病方面发挥重要作用。莱菔硫烷上调II期解毒蛋白（例如醌还原酶[QR]）的转录，而硒是产生硫氧还蛋白还原酶（TR）和谷胱甘肽过氧化物酶-1（GPx 1）所必需的，两者都具有抗氧化活性。本研究的目的是确定是否与硒的青花菜施肥增加青花菜的抗氧化能力。在用纯化的萝卜硫素、亚硒酸钠或硒化西兰花提取物处理的小鼠肝癌细胞（Hepa 1c 1c 7细胞）中，测量了过氧化氢诱导的DNA单链断裂（通过单细胞电泳、彗星试验测量）和抗氧化酶（GPx、TR和QR）的活性。当作为化学纯物质单独供应时，亚硒酸钠比萝卜硫素更有效地减少单链断裂。硒处理的青花菜提取物对DNA单链断裂的抑制作用最强，含0.71μM硒和0.08μM萝卜硫素的提取物对DNA单链断裂的抑制率达94%。一个显着的正相关（r=0.81，p=0.009）GPx 1活性和DNA单链断裂的抑制，以及24小时之间的滞后时间添加硒，萝卜硫素或花椰菜提取物和抑制单链断裂表明，一些抗氧化保护介导的硒蛋白。相反，施肥的西兰花硒降低的能力，西兰花提取物诱导QR活性。这些结果表明，硒和萝卜硫素，单独或作为西兰花的组成部分，可能有助于降低氧化应激。他们进一步表明，硒对于降低氧化应激是最重要的，但最大限度地提高西兰花的硒含量也可能会损害其诱导II期解毒蛋白的能力。
Depending on growth conditions, broccoli may be enriched in the isothiocyanate sulforaphane and/or the mineral selenium (Se); both compounds may play an important role in the reduction of intracellular oxidative stress and chronic disease prevention. Sulforaphane up-regulates transcription of Phase II detoxification proteins (e.g. quinone reductase [QR]), whereas Se is needed for the production of thioredoxin reductase (TR) and glutathione peroxidase-1 (GPx1), both of which exhibit antioxidant activity. The objective of the present study was to determine whether the fertilization of broccoli with Se increases the antioxidant ability of broccoli. Hydrogen peroxide-induced DNA single-strand breaks (measured by single cell electrophoresis, Comet assay) and activity of antioxidant enzymes (GPx, TR and QR) were measured in mouse hepatoma cells (Hepa 1c1c7 cells) treated with purified sulforaphane, sodium selenite or extracts of selenized broccoli. When supplied separately as chemically pure substances, sodium selenite was more effective than sulforaphane for reduction of single-strand breaks. Se-fertilized broccoli extracts were the most effective for reduction of DNA single-strand breaks, and extracts that contained 0.71μM Se and 0.08μM sulforaphane inhibited 94% of DNA single-strand breaks. A significant positive association (r=0.81, p=0.009) between GPx1 activity and inhibition of DNA single-strand breaks as well as a 24h lag time between addition of Se, sulforaphane or broccoli extract and inhibition of single-strand breaks suggests that some of the antioxidant protection is mediated through selenoproteins. Conversely, fertilization of broccoli with Se decreased the ability of broccoli extract to induce QR activity. These results demonstrate that Se and sulforaphane, alone or as a component of broccoli, may help decrease oxidative stress. They further suggest that Se is the most important for decreasing oxidative stress, but maximizing the Se content of broccoli also may compromise its ability to induce Phase II detoxification proteins.