Free radical-scavenging properties of lignin
Free radical-scavenging properties of lignin
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DOI：
10.1080/01635589809514637
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发表时间：
1998-01-01
影响因子：
2.9
通讯作者：
Gau, RJ
中科院分区：
文献类型：
--
作者：
Lu, FJ;Chu, LH;Gau, RJ
木质素是膳食纤维的主要成分之一。它是一种复杂的疏水分子，通常与杂木聚糖一起存在于细胞壁中。我们的实验数据表明，木质素是一种自由基清除剂。当使用NADH-吩嗪硫酸甲酯-硝基蓝四唑鎓自由基产生系统时，引起黄嘌呤氧化酶尿酸产生50%抑制（IC 50）的46.29 μ g/ml的碱-木质素浓度是超氧阴离子自由基的清除剂。分光光度法测定表明，碱木质素的IC 50为59.08 μ g/ml，可抑制与超氧阴离子自由基产生相关的酶之一黄嘌呤氧化酶的活性，并呈现混合型非竞争性抑制模式。使用脱氧核糖方法，我们发现碱木质素是一种羟基自由基清除剂，IC 50为250 μ g/ml，使用硫代巴比妥酸方法，我们可以看到碱木质素抑制非酶和酶脂质过氧化，IC 50分别为72和100 μ g/ml。碱木质素还阻碍葡萄糖-6-磷酸脱氢酶的活性，葡萄糖-6-磷酸脱氢酶是另一种与超氧阴离子自由基的产生有关的酶，IC 50为123.6 μ g/ml，并以剂量依赖的方式阻碍癌细胞（HeLa）的生长和存活。我们的实验结果表明膳食纤维中木质素的自由基清除活性可能涉及纤维的另一种机制，结肠癌的相互作用。我们还认为膳食纤维预防结肠癌的能力可能部分取决于膳食纤维中木质素的含量以及木质素的自由基清除能力。
Lignin is one of the major components of dietary fiber. It is a complex hydrophobic molecule that typically occurs in cell walls with heteroxylans. Our experimental data show that lignin is a free radical scavenger. When the NADH-phenazine methosulfate-nitro blue tetrazolium free radical-producing system is used, an alkali-lignin concentration of 46.29 mu g/ml that causes 50% inhibition of uric acid production by xanthine oxidase (IC50) is a scavenger of superoxide anion radicals. Spectrophotometric assay has shown that alkali-lignin with an IC50 of 59.08 mu g/ml inhibits the activity of xanthine oxidase, one of the enzymes related to the production of superoxide anion radicals, and presents a mixed-type noncompetitive inhibition pattern. Using the deoxyribose method, we have found that alkali-lignin is a hydroxyl radical scavenger with an IC50 of 250 mu g/ml, and using the thiobarbituric acid method, we can see that alkali-lignin inhibits nonenzymatic and enzymatic lipid peroxidation with an IC50 of 72 and 100 mu g/ml, respectively. Alkali-lignin also hinders the activity of glucose-6-phosphate dehydrogenase, another enzyme related to the generation of superoxide anion radicals, with an IC50 of 123.6 mu g/ml, and obstructs the growth and viability of cancer (HeLa) cells in a dose-dependent manner Our experimental results suggest another mechanism whereby the free radical-scavenging activity of lignin in dietary fiber may be involved in the fiber-colon cancer interaction. We also suggest that the ability of dietary fiber to protect against colon cancer may be partly determined by the amount of lignin in dietary fiber as well as the free radical-scavenging ability of lignin.