growth inhibition and apoptosis induction by vincetoxicum pumilum decne. on hl-60 and k562 leukemic cell lines

conclusions collectively, the v. pumilum extracts showed remarkable cytotoxic activity and merit further investigation as anticancer agents. results the ch2cl2 fraction of v. pumilum showed a potent dose-related inhibitory effect on cell viability. the ch2cl2 fraction showed ic50 values of 8.3 and 12.5 µg/ml in the k562 and hl-60 cell lines, respectively. a sub-g1 peak in the flow cytometry histograms of treated cells induced by the ch2cl2 fraction suggested an induction of apoptosis. further, both the parent methanol extract and its ch2cl2 sub-fraction increased the expression of the pro-apoptotic protein bax and of cleaved parp in the cells. background phenanthroindolizidine alkaloids have been isolated from many species of vincetoxicum. these alkaloids show promising anti-cancer activity and are a current topic of interest. objectives the inhibition of cell viability by different extracts of v. pumilum was measured in vitro in hl-60 and k562 human leukemic cancer cell lines and in freshly-isolated peripheral blood lymphocytes as a normal cell line. materials and methods using resazurin staining, cell viability was measured. in addition, the presence of apoptotic cells was determined using propidium iodide (pi) staining of dna fragments (sub-g1 peak). employing western blot analysis, levels of bax, bcl-2, and parp cleavage were measured.