Cytotoxicity against human leukemic cell lines, and the activity on the expression of resistance genes of flavonoids from Platanus orientalis

The cytotoxic activity of three flavonoids, belonging to the kaempherol ser ies, was evaluated against 15 human leukemic cell lines. Flavonoids bearing acyl substituants, 2 and 3, were found to be the most active compounds. A further compound, I, was examined for its ability to modulate the expressio n of MDR-1 and GST-pi resistance genes and compounds 2 and 3 for their effe ct on the uptake of [H-3]-thymidine as a marker of DNA synthesis.