title: Protective effect of persimmon peel polyphenol against high glucose-induced oxidative stress in LLC-PK(1) cells.
abstract: The effect of persimmon peel polyphenol (PPP) on high glucose-induced oxidative stress was investigated using LLC-PK(1) cells, which is susceptible to oxidative stress. High-concentration glucose (30 mM) treatment induced LLC-PK(1) cell death, but high molecular-PPP (HMPPP) and low molecular-PPP (LMPPP), at concentrations of 5 or 10 microg/ml, significantly inhibited the high glucose-induced cytotoxicity. Furthermore, treatment with HMPPP or LMPPP dose-dependently reduced the intracellular reactive oxygen species level increased by 30 mM glucose. In addition, nitric oxide, superoxide and peroxynitrite levels were increased by 30 mM glucose treatment, but they were concentration-dependently inhibited by HMPPP or LMPPP treatment. High glucose levels induced the overexpressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, but HMPPP or LMPPP treatment reduced the overexpressions of these proteins. HMPPP or LMPPP also inhibited the nuclear translocation of nuclear factor-kappa B (NF-kappaB) induced by 30 mM glucose in LLC-PK(1) cells. In particular, LMPPP exhibited stronger inhibitory activities on high glucose induced oxidative stress than HMPPP. These findings indicate the potential benefits of persimmon peel as a valuable source of antioxidants in the diabetic condition which will reduce the oxidative stress induced by hyperglycemia.
authors.affiliation: Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan. yokozawa@inm.u-toyama.ac.jp
authors.forename: Takako
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Young Ae
authors.initials: YA
authors.lastname: Kim
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Young A
authors.initials: YA
authors.lastname: Lee
authors.forename: Gen-Ichiro
authors.initials: G
authors.lastname: Nonaka
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D029788:Diospyros / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D005638:Fruit / Q000737:chemistry; D005947:Glucose / Q000494:pharmacology*; D018374:LLC-PK1 Cells; D008970:Molecular Weight; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D030421:Peroxynitrous Acid / Q000378:metabolism; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols; D026361:Reactive Nitrogen Species / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013552:Swine
chemical_list: D005419:Flavonoids; D016328:NF-kappa B; D010636:Phenols; D059808:Polyphenols; D026361:Reactive Nitrogen Species; D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D005947:Glucose