RESUMO
Aim To study effect of the extract of Fagopynum cymosum(Fr4) on the apoptosis and telomeraseactivity in human leukemia HL-60 cells.Methods HL-60 cells were treated with Fr4 and inhibition of proliferation was measured with MTT assay.Cell morphology before and after the treatment was examined with light and electron microscopy.FILC-Annexin-V and PI double staining was used to detect cell membrane-mediated apoptosis by FCM.DNA fragmentations were analyzed with DNA gel electrophoresis.Furthermore,telomerase activity was determined with PCR-ELISA-based telomeric repeat amplification(TRAP).Results The proliferation of HL-60 cells was inhibited by Fr4 with an IC_(50) of 115 mg?L~(-1).Typical morphology and biochemical feature of apoptosis was observed with Fr4 60～240 mg?L~(-1).The percentages of early apoptosis cells were increased in a dose-dependent manner.Telomerase activity was decreased in a dose-dependent manner during the process of apoptosis.Conclusion Fr4 induced apoptosis in HL-60 cells.Down-regulation of the telomerase activity in HL-60 cells might be contributed to Fr4-induced apoptosis.