Effect of quercetin and chrysin and its association on viability and cell cycle progression in MDA-MB-231 and MCF-7 human breast cancer cells.

Pharmacological properties of flavonoids have been reported, with an anticancer role amongst them, however, its mechanisms are not fully elucidated. In this study, the activity of quercetin and chrysin towards MCF-7 and MDA-MB-231 breast cancer cells was investigated. Cellular viability was determined after treatment with the compounds in different concentrations for 24 h. Secondly, cells were treated with fixed concentration of chrysin and different concentrations of quercetin with preincubation for 1 h. Both compounds inhibited cellular proliferation in dose-dependent manner. The association showed improvement in their cytotoxicity, more expressively with preincubation of quercetin. Quercetin and chrysin association induced cell cycle arrest in sub-G0/G1 phase in MDA-MB-231 cells, modified the expression of caspases-3 and -8,-8, inducing late apoptosis cell death. Taken together, our results demonstrate that both flavonoids inhibited cells growth in a dose-dependent manner and the association of quercetin improved chrysin's toxic effect over the cell lines.