Variation in Free Radical Yields from US Marketed Cigarettes

Free radicals in tobacco smoke are thought to be an important cause of smoking-induced diseases, yet the variation in free radical exposure to smokers from different brands of commercially available cigarettes is unknown. We measured the levels of highly reactive gas-phase and stable particulate -phase radicals in mainstream cigarette smoke by electron paramagnetic resonance(EPR) spectroscopy with and without the spin-trapping agent phenyl-N-tert-butylnitrone (PBN), respectively, in 27 popular US cigarettes and the 3R4F research cigarette, machine-smoked according to the FTC protocol. We find a 12-fold variation in the levels of gas -phase radicals (1.2 to 14 nmol per cigarette) and a 2-fold variation in the amounts of particulate -phase radicals (44 to 96 pmol per cigarette) across the range of cigarette brands. Gas and particulate -phase radicals were highly correlated across brands (rho = 0.62,p < 0.001). Both radicals mere correlated with TPM (gas -phase: rho = 0.38, p= 0.04; particulate-phase: rho = 0.44, p 0.02) and ventilation (gas- and tar -phase: rho = -0.58, p = 0.001), with ventilation explaining nearly 30% of the variation in radical levels across brands. Overall, our findings of significant brand variation in free radical delivery under standardized machine-smoked conditions suggest that the use of certain brands of cigarettes may be associated with greater levels of oxidative stress in smokers.