8‐Hydroxyquinolines: In Vitro Inhibition of Plaque Formation and Partition Coefficients

8-Hydroxyquinolines with the Potential for Long-Term Anticaries Activity: Design, Synthesis, and In Vitro Evaluation

“…In view of the fact that all three 8-hydroxyquinoline compoundes were essentially equal in antibacterical activity, the greater residual antiplaque activity of the two ester derivatives relative to 8-hydroxyquinoline hydrochloride indicates that the benzoate and para-(fluorosulfonyl ) -benzoate groups apparently enhanced the adsorption of these two derivatives on the tooth surface. This result may be due to a combination of three factors: (1) the ester derivatives are less soluble in water than 8-hydrozyquinoline hydrochloride, and therefore, the esters are less likely to be removed from the pretreated teeth during the water wvaslling step of the test procedure; (2) hydrophobic interactions between the benzene ring of the ester group and the tooth surface may enhance adsorption; and (3) polar interactions between the additional oxygen atoms in the ester group and the tooth surface may enhance adsorption. The degree to which these hydrophobic and polar interactions enhance adsorption of molecules of this type is undoubtedly affected by the positioning of the molecule relative to binding sites on the tooth surface.…”

Activity of Three 8-Hydroxyquinoline Derivatives Against In Vitro Dental Plaque

“…Earlier studies demonstrated that various 8-hydroxyquinoline derivatives inhibited in vitro accumulation of the cariogenic microorganism Streptococcus mutans on cleaned enamel surfaces which had been repeatedly immersed in these agents (11,12). In the study reported herein, attempts were made to determine the efficacy in vitro of three 8-hydroxyquinoline compounds, viz., 8-hydroxyquinoline sulfate (HQS; Eastman Organic), 5-chloro-7-iodo-8-quinolinol (CIQ; Pfaltz and Bauer), and 5,7-dichloro-8-hydroxyquinoline (DCHQ; Aldrich Chemical), against preformed intact plaques of pure cultures of S. mutans 6715-13, S. sanguis ATCC 10558, Actinomyces viscosus M-100, and A. naeslundii ATCC 12104.…”

“…Other investigators have employed dimethyl sulfoxide to dissolve these compounds (11,12). However, in these studies, such a procedure was deemed unsatisfactory because dimethyl sulfoxide was found to inhibit culture acid production, but this was not so for polyethylene glycol 200.…”