title: Cocoa flavonoid epicatechin protects pancreatic beta cell viability and function against oxidative stress.
abstract: METHODS
  Diabetes mellitus is associated with reductions in glutathione, supporting the critical role of oxidative stress in its pathogenesis. Antioxidant food components such as flavonoids have a protective role against oxidative stress-induced degenerative and age-related diseases. Flavonoids such as epicatechin (EC) constitute an important part of the human diet; they can be found in green tea, grapes, and cocoa and possess multiple biological activities. This study investigates the chemo-protective effect of EC against oxidative stress induced by tert-butylhydroperoxide (t-BOOH) on Ins-1E pancreatic beta cells.
  
  
  RESULTS
  Cell viability, oxidative status, phosphorylated Jun kinase (p-JNK) expression, and insulin secretion were evaluated. Ins-1E cells treatment with 5-20 μM EC for 20 h evoked no cell damage and enhanced antioxidant enzymes and insulin secretion. Addition of 50 μM t-BOOH for 2 h induced reactive oxygen species, p-JNK, and carbonyl groups and decreased GSH and insulin secretion. Pretreatment of cells with EC prevented the t-BOOH-induced reactive oxygen species, carbonyl groups, p-JNK expression and cell death, and recovered insulin secretion.
  
  
  CONCLUSIONS
  Ins-1E cells treated with EC showed a remarkable recovery of cell viability and insulin secretion damaged by t-BOOH, indicating that integrity of secreting and surviving machineries in the EC-treated cells was notably protected against the oxidative insult.
authors.affiliation: Departamento de Metabolismo y Nutrición; Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN - CSIC), Madrid, Spain; Centro de Investigación Biomédica en red de Diabetes y Enfermedades Metabólicas Asociadas (ISCIII), Madrid, Spain.
authors.forename: María Ángeles
authors.initials: MÁ
authors.lastname: Martín
authors.forename: Elisa
authors.initials: E
authors.lastname: Fernández-Millán
authors.forename: Sonia
authors.initials: S
authors.lastname: Ramos
authors.forename: Laura
authors.initials: L
authors.lastname: Bravo
authors.forename: Luis
authors.initials: L
authors.lastname: Goya
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002099:Cacao / Q000737:chemistry*; D002392:Catechin / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D020011:Protective Agents / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000633:toxicity
chemical_list: D000975:Antioxidants; D007328:Insulin; D020011:Protective Agents; D017382:Reactive Oxygen Species; D002392:Catechin; D020122:tert-Butylhydroperoxide; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005978:Glutathione
keywords: Antioxidant defenses; Cocoa flavanols; Dietary polyphenols; Oxidative biomarkers; Type 2 diabetes mellitus