RESUMO
Production and the mechanism of the interactions of free radicals generated by stimulated macrophages in the presence of luminol and a free radical inhibitor was investigated to determine the possibility of using luminol-dependent chemiluminescence for studying photodynamic effects in biology. Earlier measurements have been revisited and additional experiments performed indicating that oxidation products of luminol neither inhibit the in vitro formation of radicals nor quench CL. Simulation based on the mechanism suggested revealed that the likely value for the rate constant of the primary step between luminol and superoxide anion radicals producing luminol radicals is 5x10(2)-1x10(3) M-1s-1. It has been established that the ratio of the concentration of radicals generated by the biological system to that formed by oxidation of luminol exceeds 10(3); that is, the contribution of the latter is negligible and the system is appropriate to measure quantitatively the effect of excited photosensitizers on free radicals.
