title: Protective effect of Viola tricolor and Viola odorata extracts on serum/glucose deprivation-induced neurotoxicity: role of reactive oxygen species.
abstract: OBJECTIVE
  Oxidative stress plays a key role in the pathophysiology of brain ischemia and neurodegenerative disorders. Previous studies indicated that Viola tricolor and Viola odorata are rich sources of antioxidants. This study aimed to determine whether these plants protect neurons against serum/glucose deprivation (SGD)-induced cell death in an in vitro model of ischemia and neurodegeneration.
  
  
  METHODS
  The PC12 neuronal cells were pretreated for 4 hr with 1 to 50 µg/ml of V. odorata or V. tricolor hydroalcoholic extracts followed by 24 hr incubation under SGD condition. Cell viability was evaluated by 4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide assay. The level of intracellular reactive oxygen species (ROS) was quantitated by flow cytometry using 2',7'- dichlorofluorescin diacetate as a probe.
  
  
  RESULTS
  SGD condition led to significant decrease in cell viability (p<0.001). Pretreatment with both V. tricolor and V. odorata extracts reduced the SGD-induced cytotoxicity. SGD resulted in a significant increase in intracellular ROS production (p<0.001). Both extracts at concentrations of 25 and 50 µg/ml could reverse the increased ROS production (p<0.05).
  
  
  CONCLUSIONS
  Results of the present study showed that V. tricolor and V. odorata protect neuronal cells against SGD-induced cell death, at least in part, by their antioxidant activities. Further studies on the possible application of these plants in prevention or treatment of cerebral ischemia and neurodegenerative diseases seem to be warranted.
authors: Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Medical Toxicology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Seyed Hadi
authors: SH
authors: Mousavi
authors: Payam Noor Shargh, Tehran University of Basic Sciences, Tehran, Iran.
authors: Behnaz
authors: B
authors: Naghizade
authors: Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Solmaz
authors: S
authors: Pourgonabadi
authors: Pharmacological Research Center of Medicinal Plants, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Ahmad
authors: A
authors: Ghorbani
keywords: PC12; Reactive oxygen species; Viola odorata; Viola tricolor