Mechanism of Antimicrobial Effect of Quinone Compounds

It has been observed that, in the culture medium, the toxicity of p-benzoquinone on bakers’ yeast decreases with time, and the decreasing process was examined from the view point of chemical reaction of quinone with the component of the medium. As a result, it was shown that quinone concentration decreases by its 1,4-addition reaction with amino radicals of the component of the medium, and it was concluded that the inhibiting effect of quinone on the yeast growth is determined by the velocity of death of the yeast by the toxicity of quinone and that of inactivation of the toxicity by the addition reaction. The interaction between microbes (bakers’ yeast, Escherichia coli and Staphylococcusaureus) and quinone compounds (p-benzoquinone (BQ), 1, 4-naphthoquinone (NQ) and 2-methyl-1,4-naphthoquinone (VKa)) was examined in relation to the mechanism of the antimicrobial effect of quinone compounds. As a result, quinone compounds were divided in two types by the mechanism of growth inhibiting effect, i.e., the germicidal quinones such as BQ and NQ, and the microbe-static quinone such as VK3, though all of these quinones were observed to prolong the lag phase of the microbe growth without producing any other effect. In this case, it was considered that the germicidal activity depends upon the activity of 1,4-addition reaction with amino compounds, and that the microbe-static action depends upon the disorder of the electron transfer in the cell metabolism by the microbial reduction of quinone.