Cytotoxic activity of steroidal saponins against human oral tumor cell lines

Three steroidal saponins showed higher cytotoxicity against human oral squa mous cell carcinoma cell lines (HSC-2), as compared with normal human gingi val fibroblasts HGF. Tumor specificity of saponins exceeded that of tannins and flavonoids. Agarose gel electrophoresis showed that saponins failed to induce internucleosomal DNA fragmentation, but produced large DNA fragment s in both HSC-2 cells and human promyelocytic leukemic HL-60 cells. In cont rast to epigallo-catechin gallate or gallic acid, cytotoxic activity of sap onins was not significantly affected by metals (Co2+, Cu2+ Fe3+) nor by ant ioxidants (sodium ascorbate, N-acetyl-L-cysteine, catalase). Furthermore, s aponins did not produce radicals (detected by ESR spectroscopy) nor oxidati on potential (measured by NO monitor). These data suggest that an oxidation -mediated mechanism is not involved in the cytotoxicity induced by steroida l saponins.