title: Methanolic extract of onion (Allium cepa) attenuates ischemia/hypoxia-induced apoptosis in cardiomyocytes via antioxidant effect.
abstract: BACKGROUND
  Although there is growing awareness of the beneficial potential of onion intake to lower the risk of cardiovascular disease, there is little information about the effect of onion on ischemic heart injury, one of the most common cardiovascular diseases.
  
  
  OBJECTIVE
  This study investigates the effect of the methanol-soluble extract of onion on ischemic injury in heart-derived H9c2 cells in vitro and in rat hearts in vivo. The underlying mechanism is also investigated.
  
  
  METHODS
  To evaluate the effect of onion on ischemia-induced cell death, LDH release and TUNEL-positivity were assessed in H9c2 cells, and the infarct size was measured in a myocardial infarct model. To investigate the mechanism of the cardioprotection by onion, the reactive oxygen species (ROS) level and the mitochondrial membrane potential (DeltaPsi(m)) were measured using an imaging technique; the caspase-3 activity was assayed, and Western blotting was performed to examine cytochrome c release in H9c2 cells.
  
  
  RESULTS
  The methanolic extract of onion had a preventive effect on ischemia/hypoxia-induced apoptotic death in H9c2 cells in vitro and in rat heart in vivo. The onion extract (0.05 g/ml) inhibited the elevation of the ROS, mitochondrial membrane depolarization, cytochrome c release and caspase-3 activation during hypoxia in H9c2 cells. In the in vivo rat myocardial infarction model, onion extract (10 g/kg) significantly reduced the infarct size, the apoptotic cell death of the heart and the plasma MDA level.
  
  
  CONCLUSIONS
  In conclusion, the results of this study suggest that the methanolic extract of onion attenuates ischemia/hypoxia-induced apoptosis in heart-derived H9c2 cells in vitro and in rat hearts in vivo, through, at least in part, an antioxidant effect.
authors.affiliation: Department of Physiology, School of Medicine, Ajou University, #5 Woncheon-dong, Suwon, 443-749, South Korea.
authors.forename: Sok
authors.initials: S
authors.lastname: Park
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Kim
authors.forename: Dong Ha
authors.initials: DH
authors.lastname: Lee
authors.forename: Soo Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Baik
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Moon
authors.forename: Se Won
authors.initials: SW
authors.lastname: Park
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Ko
authors.forename: Sei-Ryang
authors.initials: SR
authors.lastname: Oh
authors.forename: Yi-Sook
authors.initials: YS
authors.lastname: Jung
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D015687:Cell Hypoxia / Q000187:drug effects*; D003331:Coronary Vessels; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D020287:In Situ Nick-End Labeling; D007511:Ischemia / Q000188:drug therapy*; D008315:Malondialdehyde / Q000097:blood; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D019697:Onions / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D045304:Cytochromes c; D053148:Caspase 3