title: EGCG inhibit chemical reactivity of iron through forming an Ngal-EGCG-iron complex.
abstract: Accumulated evidence indicates that the interconversion of iron between ferric (Fe(3+)) and ferrous (Fe(2+)) can be realized through interaction with reactive oxygen species in the Fenton and Haber-Weiss reactions and thereby physiologically effects redox cycling. The imbalance of iron and ROS may eventually cause tissue damage such as renal proximal tubule injury and necrosis. Many approaches were exploited to ameliorate the oxidative stress caused by the imbalance. (-)-Epigallocatechin-3-gallate, the most active and most abundant catechin in tea, was found to be involved in the protection of a spectrum of renal injuries caused by oxidative stress. Most of studies suggested that EGCG works as an antioxidant. In this paper, Multivariate analysis of the LC-MS data of tea extracts and binding assays showed that the tea polyphenol EGCG can form stable complex with iron through the protein Ngal, a biomarker of acute kidney injury. UV-Vis and Luminescence spectrum methods showed that Ngal can inhibit the chemical reactivity of iron and EGCG through forming an Ngal-EGCG-iron complex. In thinking of the interaction of iron and ROS, we proposed that EGCG may work as both antioxidant and Ngal binding siderphore in protection of kidney from injuries.
authors.affiliation: Key Laboratory of Tea Biochemistry and Biotechnology, Anhui Agricultural University, 130 West Changjiang Road, Hefei, 230036, Anhui, China, baoguanhu@ahau.edu.cn.
authors.forename: Guan-Hu
authors.initials: GH
authors.lastname: Bao
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Feng-Lin
authors.initials: FL
authors.lastname: Hu
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Wan
authors.forename: Shi-Xian
authors.initials: SX
authors.lastname: Deng
authors.forename: Jonathan
authors.initials: J
authors.lastname: Barasch
mesh_terms: D000209:Acute-Phase Proteins / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D002712:Chlorides; D002853:Chromatography, Liquid; D005290:Ferric Compounds; D005296:Ferrous Compounds; D007501:Iron / Q000737:chemistry*; D000071068:Lipocalin-2; D054834:Lipocalins / Q000737:chemistry*; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013662:Tea / Q000737:chemistry
chemical_list: D000209:Acute-Phase Proteins; D000975:Antioxidants; D002712:Chlorides; D005290:Ferric Compounds; D005296:Ferrous Compounds; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D010936:Plant Extracts; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D013662:Tea; C020748:ferrous sulfate; D002392:Catechin; C045651:epigallocatechin gallate; D007501:Iron; C024555:ferric chloride