Positive Health Online

Abstract

PANDA and colleagues, Department of Biochemistry, Calcutta University College of Science, 700019, Calcutta, India, panda@ccf.org, analysed the stable oxidant components of cigarette smoke that are responsible for the breakdown of plasma, lung and heart proteins.

Background

The authors have previously reported that whole-phase cigarette smoke (CS) contains stable oxidants that cause oxidative damage and increased breakdown of protein (Free Radic. Biol. Med. 27: 1064. 1999). These effects have been shown to be completely prevented by ascorbic acid and partly prevented by glutathione .

Methodology

Results

The results of the present study demonstrated that the stable oxidants in whole-phase CS are found exclusively in the tar phase . These oxidants could almost totally account for whole-phase CS-induced oxidation of human plasma proteins and also the oxidative breakdown of microsomal proteins in guinea pig lung and heart. Tar phase CS-induced breakdown of microsomal proteins involves: 1) oxidation of the proteins by oxidants in the tar extract; then 2) rapid breakdown of the oxidized proteins by microsomal proteases. The oxidation and proteolysis caused by the oxidants of the tar phase CS could be completely prevented by ascorbic acid and partially prevented by glutathione, as evidenced by the formation of protein carbonyl and bityrosine and loss of tryptophan residues and thiol groups . Other antioxidants, such as superoxide dismutase, catalase, vitamin E, beta-carotene and mannitol, could not prevent the protein damage.

Conclusion

Adequate intake of vitamin C may help smokers avoid CS-induced oxidative damage . The specific role of the tar phase in CS-induced oxidative damage emphasizes the need for more effective cigarette filters .

References

Panda K et al. Cigarette smoke-induced protein oxidation and proteolysis is exclusively caused by its tar phase: prevention by vitamin C. Toxicology Letters 123 (1): 21-32. Aug 2001.