The Reducing Power of Human Saliva and its Component Secretions

Abstract

UMAN salivas reduce Fehling's solution and similar reagents for reducing sugars. On the assumption that the reducing material is D-glucose, the reducing sugar content has usually been found to fall between 10 and 35 mg. per 100 c.c. for salivas free of food materials. (For a summary of the past work, see Pigman and Reid,' and Lundqvist.2) The reducing power of the individual secretions composing human saliva has not been measured.The nature, origin, and amount of the endogenous reducing substance in salivas are especially important since glucose, if present, would be expected to have an important influence on the nature and growth of the oral microorganisms.3 Lundqvist2 has provided evidence that true glucose, if present in human salivas, must have a concentration of less than 1 mg. per 100 c.c. despite the much higher apparent reducing power.The present work was carried out with the purpose of determining the reducing power of the individual secretions which make up saliva. Methods for the collection of the secretions are now available.4 Further evidence also was sought for the presence of "true" sugars in saliva and of the nature of the reducing substances. EXPERIMENTAL Saliva Collections.-For obtaining "stimulated" secretions, two procedures have been used in the present work: (a) chewing paraffin, and (b) swabbing the tongue once each minute with an applicator' dipped in 1 per cent acetic acid. For the collection of whole saliva, the chewing of paraffin has been used as the only stimulation procedure, so that the saliva would not be contaminated by acetic acid. Only acetic acid has been used to stimulate the submaxillary and sublingual glands because chewing was difficult, if not impossible, with the collecting device in place. Parotid secretion was stimulated by both acetic acid and chewing paraffin.For this study, whole saliva (the mixed fluid obtained directly from the human mouth) and the individual secretions of the major glands have been collected. The parotid gland secretion was collected by a suction cup.