In this study, the screening of five anthraquinones (purpurin, xanthopurpurin, rubiadin, kermisic acid and flavokermisic acid), for their free radical scavenging and antioxidant effects was carried out, using three complementary methods. DPPH (2,2'-diphenyl-1-picrylhydrazyl) revealed that purpurin has a scavenging effect with IC50 = 3.491 ± 0.014 µg/ml. Results of β-carotene/linoleic acid assay showed that kermisic and flavokermisic acids have significant inhibition of lipid peroxidation with I % = 76.1 ± 1.5% and 68.6 ± 2.5%, respectively. In addition, the ferrous ion chelating test showed that only purpurin, with small concentrations, interferes in a dose dependant manner with the formation of Fe2+-ferrozine complex. These results are promising for further studies of the biological and pathological effects of these natural products.