Variations in Biological Activity of Salivary Enzymes of Smokers

Cigarette smoke contains a considerable number of dangerous chemicals which are toxic to all parts of human body، especially to oral cavity. Human saliva is the first line of defense that encounters these toxic agents. Therefore، saliva could be thought as a non-invasive research tool to monitor alternations in biochemistry of body fluids due to toxic chemicals. The aim of this research was to investigate the effect of cigarette smoke on activity of enzymatic antioxidants of saliva including peroxidase and superoxide dismutase. In practical section، a group of 20-25 years old smoker men entered the study and their salivary antioxidants were compared with a similar group of non-smokers. Un-stimulated saliva was collected in sterile tubes and kept frozen at -70°C after being centrifuged. The activity of peroxidase and superoxide dismutase was the measured using their specific substrates under assay conditions. The results showed that، within experimental errors، the activity of peroxidase was decreased significantly in the smoker group (P≤0. 001) as compared to non-smokers. Super oxide dismutase was also less active in the saliva of smokers. It is suggested that toxic chemicals in cigarette smoke could have acted as inhibitors of mentioned enzymes in saliva of smokers. A significant decrease in saliva flow rate and pH was also observed among smokers with respect to non-smokers. Calling the important contributing role of antioxidant enzymes in the defense system of saliva opens a novel new insight into smoking habit.