Influence of tobacco smoke on the appearance of oxidative stress in patients with lung cancer and chronic obstructive pulmonary diseases

Smoking is considered to be one of the primary etiological factors of many respiratory diseases, the most serious of which are chronic obstructive pulmonary diseases (COPD) and lung carcinoma (LC). Cigarette smokers have a higher mortality rate due to LC and COPD than non-smokers . Tobacco smoke is a complex mixture of over 4 700 chemical compounds, including high concentrations of oxidant agents, capable of interacting with cell constituents. Free radicals are atoms or molecules containg an impair number of electrons, which results in an unpaired electrons in the external orbit. In the human, oxygen, by means of its derivates referred to as reactive oxygen species acts as the fundamental oxidant. Once produced, these reactive metabolites can alter cellular and metabolic structures, interact with membrane unsaturated fatty acids, thus modifying the DNA and giving rise to mutations, with proteins and polysaccharides, creating more or less substantial alterations .