title: Green tea polysaccharide-conjugates protect human umbilical vein endothelial cells against impairments triggered by high glucose.
abstract: Hot-water extracts of low-grade green tea were precipitated with ethanol, deproteinized with trichloroacetic acid, neutralized with NaOH and fractionated by DEAE-cellulose DE-52 column chromatography to yield three (3) of unexplored polysaccharide-conjugate fractions termed gTPC1, gTPC2 and gTPC3. Monosaccharide and amino acid composition, contents of total neutral sugars, proteins and moistures, HPGPC distribution and Zeta potentials of gTPC1-3 were investigated. Exposure of human umbilical vein endothelial (HUVE) cells to high glucose (33 mM) for 12h significantly decreased cell viability relative to normal glucose control (p<0.001). As compared with cell injury group, gTPC1-3 at all of three dose levels (50, 150 and 300 μg/mL) were found to possess remarkably protective effects on HUVE cells against impairments induced by high glucose in a dose-dependent manner (p<0.05, p<0.001). To contribute toward our understanding of the cell-based protection mechanism of gTPC1-3, the latter were subjected to self-oxidation of 1,2,3-phentriol assay, and their scavenging effects were observed as 55.1%, 47.6% and 47.9% at the concentration of 300 μg/mL, respectively. On the basis of the fact that high glucose-induced endothelial dysfunction involves in the overproduction of reactive oxygen species (ROS) and contributes to the vascular complications in patients with diabetes, inhibitory effects of gTPC1-3 on high glucose-mediated HUVE cell loss are, at least in part, correlated with their potential scavenging potency of ROS. Taken together, gTPC1-3 could be developed as non-cytotoxic candidates of therapeutic agent for diabetic vascular complications.
authors: Hangzhou Tea Research Institute, China COOP, Hangzhou 310016, China. biomed528@163.com
authors: Xiaoqiang
authors: X
authors: Chen
authors: Yuefei
authors: Y
authors: Wang
authors: Yalin
authors: Y
authors: Wu
authors: Baoyu
authors: B
authors: Han
authors: Yuejin
authors: Y
authors: Zhu
authors: Xiaolin
authors: X
authors: Tang
authors: Qinglei
authors: Q
authors: Sun
mesh_terms: D000595:Amino Acid Sequence; D002470:Cell Survival / Q000187:drug effects; D005591:Chemical Fractionation; D002850:Chromatography, Gel; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011134:Polysaccharides / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013662:Tea / Q000737:chemistry*; D013778:Tetrazolium Salts; D013844:Thiazoles; D014471:Umbilical Veins / Q000166:cytology*
chemical_list: D016166:Free Radical Scavengers; D010936:Plant Extracts; D010940:Plant Proteins; D011134:Polysaccharides; D017382:Reactive Oxygen Species; D013662:Tea; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue; D005947:Glucose