Methanolic extract of onion (Allium cepa) attenuates ischemia/hypoxia-induced apoptosis in cardiomyocytes via antioxidant effect.
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.
Park
Sok
S
Department of Physiology, School of Medicine, Ajou University, #5 Woncheon-dong, Suwon, 443-749, South Korea.
Kim
Mi-Young
MY
Lee
Dong Ha
DH
Lee
Soo Hwan
SH
Baik
Eun Joo
EJ
Moon
Chang-Hyun
CH
Park
Se Won
SW
Ko
Eun Young
EY
Oh
Sei-Ryang
SR
Jung
Yi-Sook
YS
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
D000975:Antioxidants; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D045304:Cytochromes c; D053148:Caspase 3