Epidemiological studies suggest that foods rich in phenolic compounds contribute to reducing the risk of cancer. They may act in different stages of the development of malignant tumors by protecting the DNA from oxidative damage. Thus, the aim of this work was to study the antioxidant activity of the commercial standards gallic, caffeic, clorogenic and ferrulic acids, catechin and quercetin, using DPPH and ORAC assays, expressed as trolox equivalents (TE µmol). It was also evaluated their antiproliferative activity and the relation between their structure and protective effects against eight different human cancer cells: U251 (glioma), UACC-62 (melanoma), MCF-7 (breast), NCI-ADR/RES (ovary), 786-0 (kidney), NCI-H460 (lung), PC-3 (prostate), OVCAR-3 (ovary) and h=HT-29 (colon). Results showed that catechin, caffeic acid, clorogenic acid, quercetin and gallic acid exhibit the highest antioxidant capacities in the DPPH assay, whereas ferrulic acid, ascorbic acid, quercetin, caffeic acid, rutin and catechin had the highest ORAC value. Furthermore, the compounds exhibit cytostatic activity against all cancer cell lines tested, with TGI50 values. The TGI parameter refers to the drug concentration for total growth inhibition, and that for killing 50% of the cells. In six cell lines except OVCAR-3 and h=HT-29, gallic acid showed notably higher growth inhibitory effect than quercetin or caffeic acid. However, catechin, caffeic and chlorogenic acids also exhibited excellent results against ovary cancer cell. Despite the apparent correlation between the structural oxidation state and antiproliferative effects of the antioxidants, further studies are necessary to elucidate the cellular mechanism underlying the antiproliferative effects in biologic systems.