Inhibition of xanthine oxidase by phytic acid and its antioxidative action
Inhibition of xanthine oxidase by phytic acid and its antioxidative action
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DOI：
10.1016/j.lfs.2003.09.040
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发表时间：
2004-02-13
期刊：
影响因子：
6.1
通讯作者：
Miura, T
中科院分区：
文献类型：
--
作者：
Muraoka, S;Miura, T
我们检查了植酸是否抑制了酶促超氧化物歧化。来源：黄嘌呤氧化酶(XO)。在黄嘌呤生成尿酸的过程中，植酸对XO的半数抑制作用(IC50)约为30 mM，而超氧化物的生成受植酸的影响较大，IC50约为6 mM，说明XO的超氧化物产生区对植酸更为敏感。植酸对小鼠肠匀浆中XO活性也有抑制作用。然而，与黄油牛奶中的XO相比，肠匀浆中超氧化物的生成对植酸的生成比尿酸的生成更敏感。植酸可抑制XO诱导的超氧化物歧化所致的脂质过氧化反应，而肌醇则不能。XO引起的ADP-Fe3+还原可被超氧化物歧化酶抑制，但植酸对其无抑制作用。结果表明，植酸干扰了启动脂质过氧化的ADP-铁-氧复合体的形成。植酸和肌醇均能抑制XO诱导的超氧化物依赖的DNA损伤。甘露醇可抑制DNA链断裂。肌醇可能是羟基自由基的清除剂。植酸的抗氧化作用可能不仅与抑制XO有关，还可能与阻止ADP-铁-氧复合体的形成有关。(C)2003 Elsevier Inc.保留所有权利。
We examined if phytic acid inhibits the enzymatic superoxide. source xanthine oxidase (XO). Half inhibition of XO by phytic acid (IC50) was about 30 mM in the formation of uric acid from xanthine, but generation of the superoxide was greatly affected by phytic acid; the IC50 was about 6 mM, indicating that the superoxide generating domain of XO is more sensitive to phytic acid. The XO activity in intestinal homogenate was also inhibited by phytic acid. However, it was not observed with intestinal homogenate that superoxide generation was more sensitive to phytic acid compared with the formation of uric acid as observed with XO from butter milk. XO-induced superoxide-dependent lipid peroxidation was inhibited by phytic acid, but not by myo-inositol. Reduction of ADP-Fe3+ caused by XO was inhibited by superoxide dismutase, but not phytic acid. The results suggest that phytic acid interferes with the formation of ADP-iron-oxygen complexes that initiate lipid peroxidation. Both phytic acid and myo-inositol inhibited XO-induced superoxide-dependent DNA damage. Mannitol inhibited the DNA strand break. Myo-inositol may act as a hydroxyl radical scavenger. The antioxidative action of phytic acid may be due to not only inhibiting XO, but also preventing formation of ADP-iron-oxygen complexes. (C) 2003 Elsevier Inc. All rights reserved.