Structure-activity studies on inhibition of Streptococcus mutans by long-chain aliphatic diamines

A series of long-chain aliphatic diamines, R1R2N(CH2)mNR3-CnH2n+1' was tested for in vitro inhibition of Streptococcus mutans. In general, high activity was found for all analogs with alkyl chains containing 14 to 18 carbons. The nature of the substituents on the remainder of the alkylenediamine were of secondary importance. N-hydroxyethyl substituents tend to decrease activity. Good correlations of activity with quadratic functions of diamine critical micelle concentrations were obtained.