Astragalin heptaacetate-induced cell death in human leukemia cells is dependent on caspases and activates the MAPK pathway

Flavonoids are naturally occurring polyphenolic compounds and are among the most promising anticancer agents. Here we demonstrate that the flavonoid derivative astragalin heptaacetate (AHA) induces cell death. This was prevented by the non-specific caspase inhibitors z-VAD-fmk and Q-VD-OPH, and reduced by the selective caspase-4 inhibitor z-LEVD-fmk. AHA-induced cell death was found to be: (i) associated with the release of cytochrome c, (ii) suppressed by the overexpression of Bcl-xL, (iii) amplified by inhibition of extracellular signal-regulated kinases (ERKs) 1/2 and c-jun NH2-terminal kinases/stress activated protein kinases (JNK/SAPK) signaling, and (iv) completely abrogated by the free-radical scavenger N-acetyl-l-cysteine.