In vitro induction of apoptosis caused by bioactive compounds extracted from Forsythia suspensa and its mechanisim in HeLa cells

Objective To study the cell inhibitory and apoptosis effect of bioactive compounds extracted from Forsythia suspensa(LQ-4) on HeLa cells in vitro,and to study the mechanism of anti-tumor activity of LQ-4.Methods LQ-4 was extracted by means of alcohol precipitation,macroporous resin chromatography,and thin-layer chromatography.Methyl thiazolyl tetrazolium(MTT) assay was used to evaluate the growth inhibition rate of HeLa cells treated by different concentrations of LQ-4.Arcridine orange/ethidium bromide(AO/EB) fluorescent staining and transmission electron microscopy(TEM) were used to observe cell morphology.Western blot was used to detect the cell apoptosis-related protein in HeLa cells treated by LQ-4(50 μg/ml) at different times.Results The anti-tumor active components(LQ-4) showed time-dose-dependent inhibitory effect on the proliferation of HeLa cells in vitro.The concentration for 50% inhibition(IC50) at 12,24,and 48 hours was 93.74,33.30,and 22.65 μg/mL,respectively.Fluorescence microscope and TEM detection showed that HeLa cells presented characteristic morphological changes of apoptosis after LQ-4 treatment.The results of western blot revealed that LQ-4(50 μg/mL) could promote the activation of the zymogen of caspase-8.Conclusion LQ-4 has an inhibitory effect on HeLa cell proliferation and could induce HeLa cell apoptosis,which is probably related to the decomposition of caspase-8 protease.