Caffeic Acid Induces Apoptosis in Human Cervical Cancer Cells Through the Mitochondrial Pathway

The anti-proliferation effect of caffeic acid (3,4-dihydroxycinnamic acid), isolated from Ocimum gratissimum Linn, on human cervical cancer cells (HeLa cells) was examined to elucidate the associated mechanism and death mode.Flow cytometry showed that caffeic acid treatment results in dramatically increased apoptosis of HeLa cells. Western blot analysis revealed that caffeic acid activates various processed caspases.Caffeic acid significantly reduced proliferation of HeLa cells in a concentration-dependent manner. Morphological evidence of apoptosis, including nuclei fragmentation was clearly observed 24 and 48 hours after exposure to caffeic acid (1 mM and 10 mM) by flow cytometry. Time-dependent inhibition was also observed. Caffeic acid decreased levels of uncleaved caspase-3 and Bcl-2, and induced cleaved caspase-3 and p53.Caffeic acid induces apoptosis by inhibiting Bcl-2 activity, leading to release of cytochrome c and subsequent activation of caspase-3, indicating that caffeic acid induces apoptosis via the mitochondrial apoptotic pathway. This also suggests that caffeic acid has a strong anti-tumor effect and may be a promising chemopreventive or chemotherapeutic agent.