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This study was carried out to assess the cytotoxicity of several new synthetic steroidal saponins against the human myeloid leukemia cell lines (HL-60 and U937) and against human melanoma cells (SK-MEL-1). Several diosgenyl glycosides analyzed showed strong cell growth inhibition which was associated with alterations in cell cycle progression and induction of apoptosis. Studies of cytochrome c release and caspase-9 activation suggest a main role of the intrinsic pathway of apoptosis in the mechanism of cytotoxicity caused by this kind of compounds.

This paper reports on the cytotoxic effect induced by a new natural steroidal saponin, icogenin, on the myeloid leukemia cell line HL-60. Icogenin was found to be a cytotoxic compound IC(50) 2.6+/-0.9microM at 72h, with growth inhibition caused by the induction of apoptosis, as determined by microscopy of nuclear changes and the fragmentation of poly(ADP-ribose) polymerase-1.

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2 alpha,3 beta-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release.