Structure--Antimicrobial Activity Relationship Comparing a New Class of Antimicrobials, Silanols, to Alcohols and Phenols

摘要

Alkyldimethylsilanols, R(CH3)2SiOH, were recently reported to exhibit unexpectedly strong antimicrobial effects. The antimicrobial activities of alkyldimethylsilanols were significantly higher than their analogous alcohols. A study of structural dependence of their antimicrobial activity was conducted with four bacteria, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis. Silanols, alcohols with structures analogous to the silanols, R(CH3)2COH, and substituted phenols were evaluated as a single class of materials. The minimum lethal concentrations (MLC) defined as the concentration required for a 7-log reduction in viable bacteria after a 1-hour exposure period were used to measure the antimicrobial activity. Octanol/water partition coefficients (log P) and H-bond acidities (& No. 8710;& No. 957;) measured as the shift in frequency of O-H stretching bands between free OH and hydrogen bonded OH to diethyl ether oxygen by infrared spectroscopy were utilized as a dispersive and polar structural parameter. The correlation established by multiple regression analysis between antimicrobial activities and structural properties of silanols and carbinols against the four bacteria was log (1/MLC) = 0.670 log P + 0.0035 & No. 8710; & No. 957; -1.836, n = 282, r = 0.96, s = 0.22. This equation and a significantly high correlation coefficient r supported the hypothesis that the lipophilic properties and the H-bond acidities are primary factors for antimicrobial action of silanols and carbinols.