The purpose of this study was to evaluate free radical scavenging abilities of an extract isolated from stem bark of Piptadeniastrum africanum (P. africa-num) tree by high sensitive Electron Paramagnetic Resonance (EPR) spectroscopy. The extract depending on concentrations exhibited in vitro high scavenging ability against the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Moreover, in ... [Show full abstract] vitro high scavenging activity towards superoxide ( • O ⁻2 ) and alkyl radicals was also found. Only in the Fenton system generating hydroxyl radicals studied extract showed pro-oxidant activity. Since in the studied in vitro systems P. africanum extract showed antioxidant and pro-oxidant properties as well, we believe that thorough and detailed studies should be carried out to clarify which components are involved in its pro-oxidant activity demonstrated in this study.