[Inhibition of superoxide-dependent processes by aminoglycoside antibiotics]

The ability of various antibiotics to inhibit superoxide anion(O-2)-mediated formation of adrenochrome from adrenaline and recovery of cytochrome c by xanthine oxidase was studied. In the adrenaline system (pH 10.2), aminoglycosides might be arranged, according to the inhibitory effect, in the following order: monomycin greater than gentamicin greater than kanamycin greater than lincomycin greater than streptomycin. In the xanthine oxidase system (pH 7.8), that order was the following: monomycin greater than gentamicin greater than lincomycin greater than greater than kanamycin. It was suggested that the antibiotic inhibition of the O-2-dependent processes at the essential sites of metabolism and/or the antibiotic involvement into the process of free radical oxidation initiated by O-2 in the cells might be one of the mechanisms of the drug action and toxicity with respect to the host.