Cytotoxicity of iridals, triterpenoids from Iris, on human tumor cell lines A2780 and K562

Six different triterpenoids (known iridals) extracted from Iris germanica L. were purified and bioassayed on two cultured human tumor cell lines: A2780 and K562 land for each one a drug-sensitive and a drug-resistant cell line). All of the tested iridals had an IC50 in the 0.1 to 5.3 mug/ml range. Some of them were shown to be more effective than doxorubicine. Toxicity of iridals on multi-drug resistance (MDR) expressing cell lines seemed to indicate that the effects of these triterpenoids are less affected by MDR than those of doxorubicine or taxol.