In vitro inhibition of catalase activity by cigarette smoke: relevance for oxidative stress

The in vitro effects of cigarette smoke on catalase activity were investigated in biological preparations from rat liver and brain using a polarographic method. In both cases cigarette smoke solutions showed a potent ability to inhibit catalase activity with a slight time dependency. The reversibility of their inhibitory activity was demonstrated by in vitro dialysis tests. The catalase inhibitory compound(s) are formed in the smoking process, are not extracted with organic solvents and appear to have a relatively low molecular weight. We also examined the effects obtained by using two different commercial blends of tobacco, achieving a major inhibition with Burley tobacco in comparison to Bright tobacco. These data suggest that the cytotoxic and mutagenic effects of cigarette smoke may be mediated by its additional capacity to enhance the generation of free radicals by inhibiting catalase activity, thus contributing to cell damage particularly during oxidative stress.