Cytotoxic activity of saponins from Camassia leichtlinii against human oral tumor cell lines

Five steroidal saponins from Camassia leichtlinii showed higher cytotoxicit y against human oral squamous cell carcinoma cells HSC-2, as compared to no rmal human gingival fibroblasts HCF. The rumor specificity of saponins vari ed considerably from sample to sample, but was generally higher than that o f tannins, flavonoids and prenylated compounds such as geranylgeraniol and vitamin K-2 (MK-2). Agarose gel electrophoresis showed that the saponins fa iled to induce internucleosomal DNA fragmentation, but produced large DNA f ragments in HSC-2 cells, whereas two saponin samples (compounds I and 5) in duced internucleosomal DNA fragmentation in human promyelocytic leukemic HL -60 cells. In contrast to epigallocatechin gallate or gallic acid, the cyto toxic activity of saponins was not significantly affected by metals (Co2+, Cu2+, Fe3+) or by antioxidants (sodium ascorbate, N-acetyl-L-cysteine, cata lase). Furthermore, the saponins did not produce radicals (detected by ESR spectroscopy) nor oxidation potential (measured by NO monitor). These data suggest that an oxidation-mediated mechanism is not involved in the cytotox icity induced by the steroidal saponins.