Chemical analysis of thiol, disulphide and total sulphur content of human saliva

Abstract

Salivary fractions were prepared from untreated, dialyzed and sonicated saliva and were assayed for thiol, disulphide, total sulphur and inorganic sulphate. Individual fractions of untreated and dialyzed preparations were analyzed for their capacity to serve as substrate sources for the production of volatile sulphur compounds, namely, H 2S and CH 3SH. The relative order of volatile sulphur production was: whole saliva > sediment > supernate > filtrate. The order correlates with the determined thiol and disulphide content of the tested fractions. Dialysis did not significantly affect the thiol and disulphide content or the capacity of the whole saliva, sediment and supernatant fractions to yield volatile sulphur compounds. As filtration through 0.2 μm membrane removed approximately 90 per cent of the thiol and disulphide content of saliva and yielded a filtrate with an extremely low capacity to serve as substrate for the production of H 2S and CH 3SH, it appears that the substrate is associated almost entirely with the cellular and particulate matter of leucocytes and epithelial cells. Sonication and filtration studies suggest that most of the substrate is in the disulphide state and derived primarily from the epithelial cell membranes in whole saliva and the sediment.