Synthesis of new oligopeptides and their scavenging abilities against active oxygen species.

The reactivities of new synthetic oligopeptides containing cysteine or histidine towards active oxygen species such as superoxide (O2-) and hydroxyl radical (.OH) were investigated by an electron spin resonance (ESR)-spin trapping method. At physiological pH values, these oligopeptides greatly suppressed the generation of .OH from the reaction of Cu(en)2 (en: ethylenediamine) with hydrogen peroxide (H2O2), although these oligopeptides did not scavenge O2-. The antioxidant mechanism of these oligopeptides is discussed.