The effects of okra (Abelmoschus esculentus Linn.) on the cellular events associated with Alzheimer's disease in a stably expressed HFE neuroblastoma SH-SY5Y cell line

Neurosci Lett. 2015 Aug 31;603:6-11. doi: 10.1016/j.neulet.2015.07.011. Epub 2015 Jul 10.

Abstract

It has been reported that persons carrying the H63D variant in their hemochromatosis (HFE) gene are at increased risk of Alzheimer's disease (AD). We investigated the possibility that okra (Abelmoschus esculentus) and quercetin could mitigate this risk factor by examining its effect on AD-associated cellular events in HFE stably expressing SH-SY5Y cells. Treatment of H63D HFE cells either with okra or quercetin significantly decreased reactive oxygen species (ROS), hydrogen peroxide (H2O2), and protein oxidation compared to untreated cells. The levels of tau phosphorylation at serine-199, serine-202, and serine-396 sites were also significantly decreased when cells were treated with okra. Exposure of the H63D and wild type (WT) cells to iron increased tau phosphorylation, but this response was decreased significantly when cells were treated with okra. The mechanism responsible for these changes appears to be related to decreased glycogen synthase kinase (GSK)-3β activity, an upstream signaling kinase of tau phosphorylation. We also established that okra treatment dramatically decreases intracellular iron levels in H63D cells compared to untreated cells. Our results provide important in vitro data on the effects of okra on various AD-associated cellular processes in H63D variant HFE cells. These results suggest okra may be beneficial in people expressing the H63D variant to reduce the risk of AD and other neurodegenerative diseases related to oxidative stress. Further in vivo studies would help confirm this.

Keywords: Alzheimer’s disease; HFE; Iron; Okra; Oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abelmoschus / chemistry*
  • Alzheimer Disease / genetics
  • Alzheimer Disease / metabolism*
  • Antioxidants / pharmacology*
  • Cell Line, Tumor
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Hemochromatosis Protein
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / metabolism*
  • Humans
  • Hydrogen Peroxide / metabolism
  • Intracellular Space / metabolism
  • Iron / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mutation
  • Neuroblastoma
  • Oxidation-Reduction
  • Oxidative Stress / drug effects
  • Phosphorylation
  • Plant Extracts / pharmacology*
  • Protein Carbonylation
  • Quercetin / analogs & derivatives
  • Quercetin / pharmacology
  • Reactive Oxygen Species / metabolism
  • tau Proteins / metabolism

Substances

  • Antioxidants
  • HFE protein, human
  • Hemochromatosis Protein
  • Histocompatibility Antigens Class I
  • Membrane Proteins
  • Plant Extracts
  • Reactive Oxygen Species
  • tau Proteins
  • isoquercitrin
  • Quercetin
  • Hydrogen Peroxide
  • Iron
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3