Quercetin and hyperthermia produce a synergistic inhibitory effect on primary human ovarian-cancer cells.

Quercetin (from 0.1 muM to 10 muM) produced a dose dependent inhibition of colony formation of cells from 4 primary ovarian tumors expressing type II estrogen binding sites (type II EBS).The combined effects of quercetin ( 10 muM) and hyperthermia (42-degrees-C) result in a significant synergistic action on three out of four tumors analyzed. Moreover, two other flavonoids tested, rutin and hesperidin, which do not bind to type II EBS, are ineffective in synergizing with hyperthermia. In conclusion our results suggest that hyperthermia could synergize the growth inhibitory activity of quercetin which is probably mediated by the flavonoid interaction with type II EBS.