Pelargonidin (PEL), a common anthocyanidin with estrogenic activity, was tested in HL-60 cells for its genotoxicity and possible antigenotoxic effects against 4-nitroquinoline 1-oxide (NQO), a potent mutagen and carcinogen which induces oxidative stress. To take into account potential interactions between phytochemicals within normal human nutrition, we evaluated a combination of PEL with the nonestrogenic phytochemical chlorogenic acid (CLA), one of the most abundant polyphenols in the human diet. PEL (<= 2 mu M) and CLA (<= 800 mu M) were nongenotoxic in the micronucleus test. We observed significant antigenotoxic effects against NQO with both compounds, but no additive interaction of PEL and CLA. Comet assay results showed a nonsignificant reduction in NQO-induced DNA damage with both compounds and their combination. Flow cytometric analysis of oxidative stress revealed significant protection against NQO-induced oxidative stress by PEL, CLA, and their combination. Furthermore, PEL and CLA prevented the NQO-induced reduction in GSH level. This could be a mechanism for the observed reduction in genotoxicity. In conclusion, the phytoestrogen PEL revealed antioxidative and antigenotoxic properties in HL-60 cells, but no significant additive interaction with the abundant nutritional polyphenol CLA under the tested conditions.