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Cardioprotection with palm oil tocotrienols: comparision of different isomers

Authors :
Dipak K. Das
Istvan Lekli
Kalanithi Nesaretam
Gergo Szabo
Istvan Bak
Samarjit Das
Manika Das
Bela Juhasz
Arpad Tosaki
Saul R. Powell
Judit Váradi
Source :
American Journal of Physiology-Heart and Circulatory Physiology. 294:H970-H978
Publication Year :
2008
Publisher :
American Physiological Society, 2008.

Abstract

A recent study from our laboratory indicated the cardioprotective ability of the tocotrienol-rich fraction (TRF) from red palm oil. The present study compared cardioprotective abilities of different isomers of tocotrienol against TRF as recently tocotrienol has been found to function as a potent neuroprotective agent against stroke. Rats were randomly assigned to one of the following groups: animals were given, by gavage, either 0.35%, 1%, or 3.5% TRF for two different periods of time (2 or 4 wk) or 0.03, 0.3, and 3 mg/kg body wt of one of the isomers of tocotrienol (alpha, gamma, or delta) for 4 wk; control animals were given, by gavage, vehicle only. After 2 or 4 wk, rats were killed, and their hearts were then subjected to 30 min of global ischemia followed by 2 h of reperfusion. Dose-response and time-response experiments revealed that the optimal concentration for TRF was 3.5% TRF and 0.3 mg/kg body wt of tocotrienol given for 4 wk. TRF as well as all the isomers of tocotrienol used in our study provided cardioprotection, as evidenced by their ability to improve postischemic ventricular function and reduce myocardial infarct size. The gamma-isoform of tocotrienol was the most cardioprotective of all the isomers followed by the alpha- and delta-isoforms. The molecular mechanisms of cardioprotection afforded by tocotrienol isoforms were probed by evaluating their respective abilities to stabilize the proteasome, allowing it to maintain a balance between prodeath and prosurvival signals. Our results demonstrated that tocotrienol isoforms reduced c-Src but increased the phosphorylation of Akt, thus generating a survival signal.

Details

ISSN :
15221539 and 03636135
Volume :
294
Database :
OpenAIRE
Journal :
American Journal of Physiology-Heart and Circulatory Physiology
Accession number :
edsair.doi.dedup.....a497e28a288a0e5d020939d1499a4ff1