Multidirectional effects of triterpene saponins on cancer cells - mini-review of in vitro studies

Triterpene saponins (saponosides) are found in a variety of higher plants and display a wide range of pharmacological activities, including expectorant, anti-inflamatory, vasoprotective, gastroprotective and antimicrobial properties. Recently, a potential anticancer activity of saponins has been suggested by their cytotoxic, cytostatic, pro-apoptotic and anti-invasive effects. At high concentrations (more than 100 µM) saponins exert cytotoxic and haemolytic effects via permeabilization of the cell membranes. Noteworthy, the inhibition of cancer cell proliferation, the induction of apoptosis and attenuation of cell invasiveness is observed in the presence of low saponin concentrations. Saponins might affect the expression of genes associated with malignancy. These alterations are directly related to the invasive phenotype of cancer cells and depend on "cellular context". It illustrates the relationships between the action of saponins, and the momentary genomic/proteomic status of cancer cells. Here, we discuss the hallmarks of anti-cancer activity of saponins with the particular emphasis on anti-invasive effect of diverse groups of saponins that have been investigated in relation to tumor therapy