SUPEROXIDE SCAVENGING ACTIVITY OF SPIN-LABELED NITROSOUREA AND TRIAZENE DERIVATIVES

Superoxide scavenging activities (SSA) of newly synthesized spin-label ed nitrosourea and triazene derivatives, and their precursor nitroxide s were investigated by the ESR/spin-trapping method using the spin tra p 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and hypoxanthine/xanthine ox idase as the superoxide-generating system. The spin-labeled nitrosoure as, triazenes and their precursor nitroxides exhibited excellent SSA, whereas clinically used nitrosourea and triazene, which do not contain the nitroxide moiety, did not show any SSA. Furthermore, it was deduc ed that these nitroxides scavenge superoxide by redox cycling between nitroxide and corresponding hydroxylamine.