Early specific free radical-related cytotoxicity of gas phase cigarette smoke and its paradoxical temporary inhibition by tar. An electron paramagnetic resonance study with the spin trap DEPMPO

Marcel Culcasi, Agnès Muller, Anne Mercier, Jean Louis Clément, Olivier Payet, Antal Rockenbauer, Véronique Marchand, Sylvia Pietri

Research output: Article

28 Citations (Scopus)


Electron paramagnetic resonance (EPR) spin trapping studies demonstrated aqueous tar particulate matter (TPM) and gas phase cigarette smoke (GPCS) to behave as different sources of free radicals in cigarette smoke (CS) but their cytotoxic implications have been only assessed in CS due to its relevance to the natural smoking process. Using a sensitive spin trapping detection with 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO), this study compared the respective roles of CS- and GPCS-derived free radicals on smoke-induced cytotoxicity and lipid peroxidation of filtered and unfiltered, machine-smoked experimental and reference cigarettes yielding a wide range of TPM yields. In buffer bubbled with CS the DEPMPO/superoxide spin adduct was the major detected nitroxide. Use of appropriate control experiments with nitric oxide radical (NO{radical dot}) or carbonyl sulfide, and a computer analysis of spin adduct diastereoisomery showed that the hydroxyl radical (HO{radical dot}) adduct of DEPMPO seen in GPCS-bubbled was rather related to metal-catalyzed nucleophilic synthesis than to direct HO{radical dot} trapping. Unexpectedly a protective effect of TPM on murine 3T3 fibroblasts was observed in early (<3 h) free radical-, GPCS-induced cell death, and carbon filtering decreased free radical formation, toxicity and lipid peroxidation in three cell lines (including human epithelial lung cells) challenged with GPCS. These results highlight an acute, free radical-dependent, harmful mechanism specific to the GPCS phase, possibly involving NO{radical dot} chemistry, whose physical or chemical control may be of great interest with the aim of reducing the toxicity of smoke.

Original languageEnglish
Pages (from-to)215-231
Number of pages17
JournalChemico-Biological Interactions
Issue number3
Publication statusPublished - dec. 15 2006


ASJC Scopus subject areas

  • Toxicology

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