Resveratrol (trans-3,4', 5-trihydroxystilbene) is a naturally occurring 
polyphenolic compound that has antiinflammatory, antioxidant, neuroprotective 
properties and acts as a chemopreventive agent. Resveratrol causes cell cycle 
arrest and induces apoptotic cell death in various types of cancer cells. In the 
current studies, the effect of resveratrol on phosphoinositide kinase-3 
(PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling 
pathway was examined in human U251 glioma cells. Resveratrol decreased both the 
expression and phosphorylation of Akt. Inhibitors of PI3K (LY294002) and Akt 
(SH-6) enhanced resveratrol-induced LDH release and caspase-3 activation. 
Resveratrol reduced phosphorylation of ribosomal protein S6 and the mTOR 
inhibitor rapamycin further enhanced resveratrol-induced cell death. These 
results suggest that the downregulation of PI3K/Akt/mTOR signaling pathways may 
be an important mediator in resveratrol-induced apoptosis in glioma cells.