Abstract
Background:
Cratoxylum formosum
(Jack) Dyer ssp.
pruniflorum
(Kurz) Gogel. (Hóng yá mù) (CF) has been used for
treatment of fever, cough, and peptic ulcer. Previously, a 50% ethanol-water extract from twigs of CF was shown
highly selective in cytotoxicity against cancer cells. This study aims to investigate the molecular mechanisms
underlying the apoptosis-inducing effect of CF.
Methods:
The cytotoxicity of CF was evaluated in the human hepatocellular carcinoma (HCC) HepG2 cell line in
comparison with a non-cancerous African green monkey kidney epithelial cell line (Vero) by a neutral red assay. The
apoptosis induction mechanisms were investigated through nuclear morphological changes, DNA fragmentation,
mitochondrial membrane potential alterations, and caspase enzyme activities.
Results:
CF selectively induced HepG2 cell death compared with non-cancerous Vero cells. A 1.5-fold higher
apoptotic effect compared with melphalan was induced by 120
μ
g/mL of the 50% ethanol-water extract of CF. The
apoptotic cell death in HepG2 cells occurred
via
extrinsic and intrinsic caspase-dependent pathways in dose- and
time-dependent manners by significantly increasing the activities of caspase 3/7, 8, and 9, decreasing the mitochondrial
membrane potential, and causing apoptotic body formation and DNA fragmentat