Assessments of salivary antioxidant activity using electron spin resonance spectroscopy

ObjectiveIn recent years, the function of saliva has been focused on evaluation of general status. The relationship between salivary antioxidant activity and periodontal disease progression is unclear. The aim of this study is to assess the relationship between periodontal disease and salivary antioxidant activity towards various reactive oxygen species (ROS) using electron spin resonance (ESR) technique.MethodsWe demonstrated that whole saliva derived rats or human subjects scavenged ROS such as superoxide (O₂^?) and hydroxyl radical (HO) using ESR spectroscopy with spin trapping agent. In addition, we assessed the relationship between antioxidants activity towards ROS and periodontal index with superoxide dismutase (SOD) activity in human subject saliva.ResultsAntioxidant activity towards O₂^? was increased by Porphyromonas gingivalis (P. gingivalis) infection in rat, although antioxidant activity towards HO was not changed. In human, a strong correlation (r = 0.88, p < 0.01) recognized between salivary antioxidant activity towards O₂^? and probing pocket depth (PPD). In addition, the intensity of salivary antioxidant activity depended on SOD activity level. SOD activity was also correlated with PPD.ConclusionsRat salivary antioxidant activity towards O₂^? was up-regulated by the inflammatory response caused by P. gingivalis infection. Similar response was recognized in human saliva with periodontal index. Additionally, a linear correlation between antioxidant activity towards O₂^? and SOD activity was verified by ESR technique. Therefore, evaluation of the salivary antioxidant activity towards O₂^? might be an effective parameter for the objective assessment of periodontal disease progression.