Background and objectives: The habit of smokeless tobacco chewing is one of the known risk factors for oral cancer. Most likely, the antioxidant defense system in dealing with free radicals induced by smokeless tobacco and prevention of oral cancer is important. Saliva is the first biological fluid that encounters the harmful products of smokeless tobacco and has antioxidant defence system able to counter toxic activities of free radical species. The aim of this study was to compare the levels of superoxide dismutase (SOD) in saliva of smokeless tobacco consumers and non- consumers.

Methods: In this study, un-stimulated saliva of 100 subjects (50 smokeless tobacco consumers and 50 non-consumers) was collected. The activity of super oxide dismutase enzyme was measured by standard biochemical methods (Marklund method) and the obtained data was analyzed by student’s unpaired ‘t’test.

Results & Conclusion: The mean activity of super oxide dismutase was significantly higher in the smokeless tobacco consumers group compared to non-consumers (p<0.001). The results of this study demonstrate that consumption of smokeless tobacco leads to increased activity of salivary super oxide dismutase. Thus, evaluating the variations in the level of SOD activity in smokeless tobacco consumers might be useful for estimating the level of oxidative stress caused. Thereby, helping in patients education regarding the ill-effects of smokeless tobacco and determining the evolution and progress of various oral diseases.

Key Words: Antioxidants; Saliva; Smokeless tobacco; Superoxide dismutase.