Is the antioxidant power of saliva, measured as reducing iron power, only a quantification of salivary uric acid?

Introduction: The main non-enzymatic salivary antioxidant is uric acid. An important and innovative test for the analysis of antioxidants in the oral cavity is the SAT test, based on the determination of iron-reducing power. It is known that uric acid forms stable complexes with ferric ion and therefore it is possible that tests based on the determination of the ironreducing power might measure only the concentration of uric acid. Objective: The aim of this paper is to demonstrate that, in particular, the SAT test quantifies the reducing power of saliva in all its components. Methods: It has been quantified uric acid and iron-reducing power in saliva sample from 29 subjects. Iron-reducing power has been morover determined in some samples fortified in vitamin C. Results: A strong and significant correlation was found between the uric acid concentration and the iron-reducing power measured (r = 0.90, p <0.01), but data are not perfectly overlapping. Iron-reducing power of samples fortified in vitamin C is directly proportional to the addiction. Conclusions: The ironreducing power of saliva is simultaneous influenced by the antioxidants and not only the uric acids. The salivary ironreducing test (i.e. SAT test) are sensitive both to uric acid and to vitamin C and likely to all salivary reducing agents. Moreover the salivary iron-reducing test are an excellent estimate of the global antioxidant power of saliva and then of the oral cavity.