【作者】 张丹；

【导师】 张捷； 朱本占；

【作者基本信息】 华中农业大学 ， 环境科学， 2009， 硕士

【摘要】 天然抗氧化物植酸和秦皮乙素用途广泛。本文以3-羧酸香豆素作为荧光探针研究了植酸、一磷酸腺苷（AMP）、三磷酸腺苷（ATP）、乙烯胺的乙酸衍生物EDTA、NTA和DTPA以及羟自由基清除剂如:二甲基亚砜（DMSO）,甲酸（HCOOH）和乙醇（CH₃CH₂OH）对Fenton体系产生羟自由基的影响,同时选取HepG2细胞作为模型,探讨了秦皮乙素对铁参与的生物反应体系的影响,8HQ-Fe与细胞作用30分钟后加入秦皮乙素。研究结果表明:植酸可促使Fenton体系产生羟自由基（·OH）;AMP和ATP对Fenton体系具有同样的促进作用;乙烯胺的乙酸衍生物EDTA、NTA和DTPA也能够促进·OH的产生;DMSO,HCOOH和CH₃CH₂OH可清除植酸-Fenton体系产生的·OH;同样,植酸可促使VO（Ⅱ）-H₂O₂反应（类Fenton体系）产生·OH;0.1 mM的8-羟基喹啉-铁（1:1）复合物对细胞有较大毒性;秦皮乙素本身对细胞不产生毒性,可保护细胞免受铁离子诱导的毒性,二者呈现一定的剂量-效应关系;秦皮乙素类似物4-甲基七叶苷原和秦皮素也具有相似的剂量-效应关系。其机理与铁的络合作用有关。该结果为进一步认识天然抗氧化物植酸和秦皮乙素提供参考。更多还原

【Abstract】 Phytic acid and esculetin has been widely used as antioxidant. In this study, coumarin-3-caroxylic acid was used as fluorescent probe to detect hydroxyl radical; meanwhile, the effect of esculetin on 8HQ-Fe-induced cell viability was investigated in HepG2 cells. Esculetin was added to the cells 30 min before the addition of 8HQ-Fe.The results indicated that: Phytic acid could markedly enhance·OH produced by ferrous iron and hydrogen peroxide; similar enhancing effects were also observed for AMP and ATP;·OH formation could be enhanced by aminoacetic chelating agents such as ethyleneamine ethylenediaminetetraacetic acid （EDTA）, diethylenetriamine-penta acetic acid （DTPA） and nitrilotriacetic acid （NTA）;·OH produced by Fe/ H₂O₂/phytic acid were markedly inhibited by·OH scanvenging agents such as dimethyl sulfoxide（DMSO）, ethanol （CH₃CH₂OH） and formate（HCOOH）; similar enhancing effect by phytic acid was observed in the reaction of vanadyl and H₂O₂ （Fenton-like reaction）. Esculetin exhibited a dose dependent protection against iron-induced cell toxicity; similar dose-dependent protection was also observed with two other esculetin derivatives such as 6,7-dihydroxy-4-methylcoumarin and 7,8-dihydroxy-6-methoxycoumarin; in the absence of non-toxic esculetin but in the presence of concentrations of 8-hydroxyquinoline-Fe（II） complex （100μM 8-hydroxyquinoline, 100μM ferrous）, cell toxicity was observed.The results are quite related to the mechanism of iron chelation, which help us know more about the property of these two antioxidants更多还原