Effect of Quinones on Acid Formation in Saliva.

Abstract

Fosdick, Fancher and Calandra 1 noted that a saliva-glucose mixture containing 1 mg per 100 cc of synthetic vitamin K (2-methyl-1,4-naphthoquinone) “forms no acid in a 4-hour incubation period, while the same mixture will produce up to 2 m.eq. of acid under the same conditions in the absence of the vitamin K.” These authors emphasized that the effect on bacterial metabolism observed by them to be a property of synthetic vitamin K and discussed the possible uses of this compound in the prevention of dental caries.

The possibility suggested itself to us that the bacterial inhibitory action of synthetic vitamin K in saliva might be due to the fact that this compound is a quinone and that its antibacterial property has no actual relation to its vitamin K activity. It was already known 2 that benzoquinone possesses a substantial bacteriostatic ability. Recently reports 3 , 4 have appeared of a remarkable bacteriostatic effect exerted in vitro by certain dimethoxy quinones related structurally to fumigatin. Fumigatin (3-hydroxy, 4-methoxy, 2:5-toluquinone), produced by Aspergillus fumigatus, in itself possesses a definite ability to inhibit the multiplication of several gram-positive organisms 5 .

All points in Fig. 1 referring to a particular quinine were determined with solutions incubated concurrently using the same lot of pooled saliva to which 10% of its weight of glucose had been added (recommendation of Fosdick et al. 1 ) Other experiments demonstrated that essentially the same results were obtained when only 2% of glucose was added to the saliva. Those quinoes which were not sufficiently soluble in water were made up in alcohol, or chloroform in the case of 2, 6-dimethoxy-benzoquinone, so that equal volumes contained equal molecular amounts of the several substance. The required volumes (0.05 to 1.0 cc) of these solutions wee added to dry 25 cc volumetric flasks and the solvent evaporated under reduced pressure so that a