Daphnoretin is a bicoumarin compound isolated from a
natural product, Wikstroemia indica, which has been used to treat many diseases. It has strong
antiviral and anti-
tumor activities. Taking the anti-
tumor activity of
daphnoretin as a starting point, the present study aimed to test the pro-apoptotic effect of
daphnoretin and its underlying mechanism in HeLa cells. The inhibitory effects of
daphnoretin on viability and proliferation of HeLa cells were determined by the MTT assay.
Daphnoretin-induced apoptotic morphological changes were analyzed by mitochondrial membrane potential and Hoechst staining. The number and stage of apoptotic HeLa cells were determined by flow cytometry. Gene expression was determined by reverse-transcription polymerase chain reaction.
Protein expression was determined by western blot. The
caspase activity of HeLa cells was detected by a
caspase-3 and
caspase-9 colorimetric assay kit. We found that
daphnoretin significantly inhibited HeLa cells' viability by the MTT assay and flow cytometry. The nuclei of the apoptotic cells exhibited strong, blue fluorescence in Hoechst staining. Bax
mRNA and
protein levels were increased while bcl-2
mRNA levels were decreased after
daphnoretin treatment.
Daphnoretin also activated both
caspase-3 and
caspase-9. These findings suggest that
daphnoretin promotes apoptosis of HeLa cells in a mitochondria-mediated way.
Daphnoretin therefore has potential to be a promising
drug to treat uterine cervix
cancer.