1999 年 26 巻 1 号 p. 2-8
The inhibitory effect of some polyols which are added in various cosmetics and toiletries as humectants, emulsion stabilizers and for some other purposes against the growth activity of Escherichia coli in liquid media was studied by a calorimetric technique. The polyols studied were 1, 2-ethanediol (ethylene glycol), 1, 2-propanediol (propylene glycol), 1, 2-butanediol (1, 2-butylene glycol), 1, 3-butanediol (1, 3-butylene glycol), 1, 2, 3-propanetiol (glycerol), 1, 2-pentanediol (1, 2-hydroxypentane), 3-(3-hydoxypropanoxy) propan-1-ol (di(propylene glycol)) and polyethylene glycol. The growth thermograms observed in the absence and the presence of increasing amounts of the polyols were analyzed to determine the inhibitory parameters, the polyol concentration which inhibits the growth of the microbes by 50% (Kμ or Kθ) and the concentration which completely prevents the growth (MICμ or MICθ). All of the polyols studied were found to exert the inhibitory effect with the 50% inhibitory concentrations between 1∼17% (W/V) for E. coli. It was also shown that the apparent affinity of the polyols to the microbial cell calculated on the basis of the Gibbs equation linearly increases with the length of their alkyl chains, indicating that the inhibitory effect of the polyols is related to their hydrophobicity.
