双链季铵盐碳链长度对杀菌效果的影响

Influence of double-quaternary ammonium chain length on germicidal efficacy

为研究碳链长度对双链季铵盐抑菌作用的影响,采用抑菌圈法研究了双八烷基二甲基氯化铵(DDAC8),双十烷基二甲基氯化铵(DDAC10)、双十二烷基二甲基氯化铵(DDAC12)、双十烷基二甲基溴化铵(DDAB10)、双十二烷基二甲基溴化铵(DDAB12)、双十八烷基二甲基溴化铵(DDAB18)6种双链季铵盐对大肠杆菌(E.coli)、枯草芽孢杆菌(B.subtilis)和金黄色葡萄球菌(S.aureus)的杀灭效果。结果表明,3种氯化物随碳链长度增加杀菌效果逐渐减弱;3种溴化物对大肠杆菌的抑制作用亦随碳链增长而减弱;对枯草芽孢杆菌抑制作用较好的是DDAB10,对金黄色葡萄球菌,DDAB10和DDAB12作用效果接近,而DDAB18效果最差。将DDAC8与其他组分复配,抑菌圈试验和定量杀菌试验结果显示复配后样品液抑菌作用明显增强。透射电镜和显微镜下分别观察细菌和脂质体在DDAC8作用时的形态变化,结果显示双链季铵盐是通过作用于细胞膜而产生杀菌效应的。

Bactericidal activities of six duplex-quaternary ammonium salts,Dioctyl dimethyl ammonium chloride（DDAC8）,Didecyl dimethyl ammonium chloride（DDAC10）,Didodecyl dimethyl ammonium chlo-ride（DDAC12）,Didecyl dimethyl ammonium bromide（DDAB10）,Didodecyl dimethyl ammonium bro-mide（DDAB12）,Dioctadecyl dimethyl ammonium bromide（DDAB18）,were evaluated by inhibition zone diame-ters against E.coli,B.subtilis and S.aureus.It was found that the antibacterial activities of the three chlorinate quaternary ammoniums are weakened with the increase of chain length,and those of the three bromide quaternary ammionium salts against E.coli are also weakened with the increase of chain length;DDAB10 has a better efficacy in killing B.subtilis;DDAB10 and DDAB12 have similar efficacies in killing S.aureus,while the efficacy of DDAB18 is relatively low.When DDAC8 was combined with other kinds of ingredients,its antibacterial activity could be markedly enhanced through suspension quantitative germicidal test and inhibitory zone diameters.Under transmission electron microscope and optical microscope,the change of cellular morphology and liposome in-duced by DDAC8 was observed,and the result suggests that duplex-quaternary ammonium kills bacteria via in-teraction with cell membranes