Inhibition of iron-mediated generation of reactive oxygen species (ROS) by a synthetic chemical might help treat many (non)infectious diseases in humans and animals. Deferoxamine (DFO) would be one of the chemicals of choice for that purpose; as a naturally occurring sideramine, the DFO is specifically used to treat patients with iron-mediated disorders and inflammatory diseases; medical application of DFO is undoubtedly increasing. In the first study, ROS scavenging effect of DFO against superoxide radical (O2־•), hydrogen peroxide (H2O2) and hydroxyl radical (OH•) was examined by chemiluminescence (CL) assays; effect of DFO on the kinetics of some CL systems was also studied. In the second study, the protective effect of DFO on DNA and neutrophils was investigated using agarose gel electrophoresis and CL systems, respectively; using cellular and acellular CL assays the effects of DFO was assessed on: CL from added OCl-, flow cytometry assays of necrosis, apoptosis, CL-based bactericidal capacity of neutrophils and phagocytosis and killing of Escherichia (E.) coli and Staphylococcus (S.) aureus by neutrophils. Briefly, isolated bovine blood neutrophils were exposed with 0 and 0.1 mM of DFO for 1 and 18 h depending on the assay. Further, blood neutrophils were exposed with the DFO for 3 h and phagocytosis and killing activities against S. aureus and E. coli were examined. Our study strongly confirms the scavenging effects of DFO on O2־•, H2O2 and OH• in the luminol and orthophenanthroline CL systems. Maximal quenching capacity of DFO was observed in Fenton's reaction where participation of catalyst, iron ions, to the CL system is central. DFO also strongly protected DNA from ROS-mediated damages. Mechanistically, the observed quenching effect of DFO on ROS clearly revealed the static part of quenching properties of DFO for ROS generation systems. Though the effect of DFO on extracellular ROS greatly diminished, the DFO-treated neutrophils showed a remarkably increased phagocytosis-depended luminal CL. No neutrophils necrosis and apoptosis was induced by DFO. Phagocytosis rates and killing of E. coli and S. aureus by DFO-treated neutrophils were significantly higher than those of non-treated ones. Our results show the extracellularily anti-oxidant and pro-phagocytic properties of pharmacologically relevant level of DFO for bovine neutrophils. Application of bovine neutrophils as a cellular model for CL system revealed that DFO behaved differently in cellular and acellular CL. The scope of the enhancing effects of the in vitro DFO on neutrophil functions should be considered in mammals as a pharmacologically relevant chemical for clinical implications.

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