Radical scavenging properties of polyamines

Di- and polyamines are effective scavengers of free radicals generated in a number of chemical and in vitro enzyme systems. Free radical production was quantified spectrophotometrically using nitroblue tetrazolium and cytochrome c or by electron spin resonance. Levels of superoxide radical formed either enzymatically with xanthine oxidase or chemically from riboflavin or pyrogallol were significantly inhibited by spermine, spermidine, putrescine and cadaverine at 10 and 50 mM. The more reactive hydroxyl radical generated by the Fenton reaction was also effectively scavenged by di- and polyamines. In addition, the production of superoxide radical by senescing microsomal membranes was inhibited by di- and polyamines, as was the superoxide-dependent conversion of 1- aminocyclopropane-1-carboxylic acid (ACC) to ethylene. The efficacy of polyamine-scavenging appears to be correlated with the extent of amination suggesting the involvement of amino groups. It is also apparent that some of the physiological effects of polyamines, in particular their propensity to inhibit lipid peroxidation and retard senescence, may be attributable to their radical-scavenging capability.