α-Phenyl-N-tert-butyl Nitrone Has Scavenging Activity Against Singlet Oxygen (1O2) and Attenuates 1O2-Induced Neuronal Cell Death

Scavenging activity of α-phenyl-N-tert-butyl nitrone (PBN) against singlet oxygen (1O2) and its effects on 1O2-induced neuronal cell death were examined. PBN at 1 – 4 mM dose-dependently suppressed 1O2 released from activated human neutrophils. PBN did not react with hydrogen peroxide or hypochlorite and did not affect myeloperoxidase activity, which are involved in the 1O2 formation in neutrophils. PBN also suppressed chemically generated 1O2 in a cell-free system. These findings collectively indicated that PBN certainly has scavenging activity against 1O2. Furthermore, PBN attenuated 1O2-induced neuronal cell death. The well-known neuroprotective effects of PBN might be attributed to its 1O2-scavenging activity.