Key Word Iadex-Polyamincs; free radicals; lipid peroxidation; senescence.
Abstnct-Diand polyamines are effective scavengers of free radicals generated in a number of chemical and in vitro enzyme systems. Free radical production was qua&&d s~trophotomet~~y using ~itroblue tetrazolium and ~t~hrome c or by electron spin resonance. Levels of superoxide radical formed either enzymatically with xanthine oxidase or chemi~~y from ribofIavin or pyrogallol were sig~~ntIy 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 l-~n~ciopro~~l~r~xylic acid (ACC) to ethylene. The efficacy of ~lya~ne-evening appears to be correlated with the extent of amination su~~~g the involvement of amino groups. It is also apparent that some of the physiolo~~l effects of polyamines, in particular their propensity to inhibit lipid ~roxi~tion and retard senescence, may be attributable to their radical-scavenging capability. Hydroxyl radicals were generated by the Fenton reaction. A, Controi; B, 25mM spermidine; C, 50mM spermidine. The amplitude for the control was 202 mm.